develop/masks/masks.c

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/*
    This file is part of darktable,
    Copyright (C) 2013-2014, 2016, 2019-2021 Aldric Renaudin.
    Copyright (C) 2013, 2016-2021 Pascal Obry.
    Copyright (C) 2013-2016 Roman Lebedev.
    Copyright (C) 2013 Simon Spannagel.
    Copyright (C) 2013-2014, 2016-2018 Tobias Ellinghaus.
    Copyright (C) 2013-2016, 2019-2020 Ulrich Pegelow.
    Copyright (C) 2016, 2018 Matthieu Moy.
    Copyright (C) 2017-2019 Edgardo Hoszowski.
    Copyright (C) 2017, 2019 luzpaz.
    Copyright (C) 2017 Peter Budai.
    Copyright (C) 2018 johannes hanika.
    Copyright (C) 2019-2020 Diederik Ter Rahe.
    Copyright (C) 2019 Jacopo Guderzo.
    Copyright (C) 2020 Chris Elston.
    Copyright (C) 2020 GrahamByrnes.
    Copyright (C) 2020 Heiko Bauke.
    Copyright (C) 2020-2021 Hubert Kowalski.
    Copyright (C) 2020-2021 Ralf Brown.
    Copyright (C) 2021 darkelectron.
    Copyright (C) 2021 Hanno Schwalm.
    Copyright (C) 2021 Philipp Lutz.
    Copyright (C) 2022-2023, 2025-2026 Aurélien PIERRE.
    Copyright (C) 2022 Martin Bařinka.
    Copyright (C) 2023 Alynx Zhou.
    Copyright (C) 2023 Luca Zulberti.
    Copyright (C) 2025-2026 Guillaume Stutin.
    
    darktable is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
    
    darktable is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
    
    You should have received a copy of the GNU General Public License
    along with darktable.  If not, see <http://www.gnu.org/licenses/>.
*/
#include "common/darktable.h"
#include "gui/gdkkeys.h"
#include "develop/masks.h"
#include "develop/develop.h"
#include "bauhaus/bauhaus.h"
#include "common/debug.h"
#include "common/math.h"
#include "common/mipmap_cache.h"
#include "control/conf.h"
#include "common/undo.h"
#include "develop/blend.h"
#include "develop/dev_pixelpipe.h"
#include "develop/imageop.h"
#include "develop/imageop_gui.h"
#include <stdint.h>
 
gboolean dt_masks_point_is_within_radius(const float point_x, const float point_y,
                                         const float center_x, const float center_y,
                                         const float squared_radius)
{
  const float delta_x = point_x - center_x;
  const float delta_y = point_y - center_y;
  const float squared_distance = delta_x * delta_x + delta_y * delta_y;
  return squared_distance <= squared_radius;
}
 
int dt_masks_find_closest_handle_common(dt_masks_form_t *mask_form,
                                        dt_masks_form_gui_t *mask_gui, int form_index, int node_count_override,
                                        dt_masks_border_handle_fn border_handle_cb,
                                        dt_masks_curve_handle_fn curve_handle_cb,
                                        dt_masks_node_position_fn node_position_cb,
                                        dt_masks_distance_fn distance_cb,
                                        dt_masks_post_select_fn post_select_cb,
                                        void *user_data)
{
  if(IS_NULL_PTR(mask_form) || IS_NULL_PTR(mask_form->points)) return 0;
  if(!mask_gui->creation && mask_gui->group_selected != form_index) return 0;
 
  dt_masks_form_gui_points_t *gui_points
      = (dt_masks_form_gui_points_t *)g_list_nth_data(mask_gui->points, form_index);
  if(IS_NULL_PTR(gui_points)) return 0;
 
  // Handle detection in backbuffer space.
  const float cursor_radius = DT_GUI_MOUSE_EFFECT_RADIUS;
  const float cursor_radius2 = cursor_radius * cursor_radius;
  const float cursor_x = mask_gui->pos[0];
  const float cursor_y = mask_gui->pos[1];
  const int selected_node = dt_masks_gui_selected_node_index(mask_gui);
 
  // Keep track of current state, in case we need to refresh total deselection.
  const gboolean need_refresh_anyway = dt_masks_gui_was_anything_selected(mask_gui);
 
  mask_gui->form_selected = FALSE;
  mask_gui->border_selected = FALSE;
  mask_gui->source_selected = FALSE;
 
  mask_gui->node_hovered = -1;
  mask_gui->handle_hovered = -1;
  mask_gui->seg_hovered = -1;
  mask_gui->handle_border_hovered = -1;
 
  if(mask_gui->node_dragging >= 0)
  {
    mask_gui->node_hovered = mask_gui->node_dragging;
    return 1;
  }
  if(mask_gui->handle_dragging >= 0)
  {
    mask_gui->handle_hovered = mask_gui->handle_dragging;
    return 1;
  }
  if(mask_gui->handle_border_dragging >= 0)
  {
    mask_gui->handle_border_hovered = mask_gui->handle_border_dragging;
    return 1;
  }
  if(mask_gui->seg_dragging >= 0)
  {
    mask_gui->seg_hovered = mask_gui->seg_dragging;
    return 1;
  }
 
  const int node_count = (node_count_override >= 0) ? node_count_override
                                                    : (int)g_list_length(mask_form->points);
 
  const gboolean has_bezier_layout = mask_form->uses_bezier_points_layout;
  const gboolean can_test_nodes = (!IS_NULL_PTR(node_position_cb)) || has_bezier_layout;
  const int first_node_index = has_bezier_layout ? 0 : 1; // skip center node for non-bezier shapes
  const gboolean has_selected_node = (node_count > 0) && can_test_nodes
                                     && (mask_gui->group_selected == form_index)
                                     && selected_node >= first_node_index && selected_node < node_count;
 
  if(has_selected_node)
  {
    // Current node's border handle (feather handle).
    float handle_x = NAN;
    float handle_y = NAN;
    if(border_handle_cb
       && border_handle_cb(gui_points, node_count, selected_node, &handle_x, &handle_y, user_data)
       && dt_masks_point_is_within_radius(cursor_x, cursor_y, handle_x, handle_y, cursor_radius2))
    {
      mask_gui->handle_border_hovered = selected_node;
      return 1;
    }
 
    // Current node's curve handle.
    if(!dt_masks_node_is_cusp(gui_points, selected_node) && curve_handle_cb)
    {
      curve_handle_cb(gui_points, selected_node, &handle_x, &handle_y, user_data);
      if(dt_masks_point_is_within_radius(cursor_x, cursor_y, handle_x, handle_y, cursor_radius2))
      {
        mask_gui->handle_hovered = selected_node;
        return 1;
      }
    }
 
    // Current node itself.
    float node_x = NAN;
    float node_y = NAN;
    if(node_position_cb)
    {
      node_position_cb(gui_points, selected_node, &node_x, &node_y, user_data);
    }
    else if(has_bezier_layout)
    {
      node_x = gui_points->points[selected_node * 6 + 2];
      node_y = gui_points->points[selected_node * 6 + 3];
    }
    if(!isnan(node_x) && !isnan(node_y)
       && dt_masks_point_is_within_radius(cursor_x, cursor_y, node_x, node_y, cursor_radius2))
    {
      mask_gui->node_hovered = selected_node;
      return 1;
    }
  }
 
  if(can_test_nodes)
  {
    for(int node_index = first_node_index; node_index < node_count; node_index++)
    {
      float node_x = NAN;
      float node_y = NAN;
      if(node_position_cb)
      {
        node_position_cb(gui_points, node_index, &node_x, &node_y, user_data);
      }
      else if(has_bezier_layout)
      {
        node_x = gui_points->points[node_index * 6 + 2];
        node_y = gui_points->points[node_index * 6 + 3];
      }
      if(!isnan(node_x) && !isnan(node_y)
         && dt_masks_point_is_within_radius(cursor_x, cursor_y, node_x, node_y, cursor_radius2))
      {
        mask_gui->node_hovered = node_index;
        return 1;
      }
    }
  }
 
  if(IS_NULL_PTR(distance_cb)) return 0;
 
  // Segment or shape hit tests.
  int inside = 0;
  int inside_border = 0;
  int near_segment = -1;
  int inside_source = 0;
  float nearest_distance = 0.0f;
  distance_cb(cursor_x, cursor_y, cursor_radius, mask_gui, form_index, node_count, &inside, &inside_border,
              &near_segment, &inside_source, &nearest_distance, user_data);
 
 
  if(inside_source)
  {
    mask_gui->form_selected = TRUE;
    mask_gui->source_selected = TRUE;
    if(post_select_cb) post_select_cb(mask_gui, inside, inside_border, inside_source, user_data);
    return 1;
  }
  if(inside_border)
  {
    mask_gui->form_selected = TRUE;
    mask_gui->border_selected = TRUE;
    if(post_select_cb) post_select_cb(mask_gui, inside, inside_border, inside_source, user_data);
    return 1;
  }
  if(near_segment >= 0)
  {
    if(near_segment < node_count)
      mask_gui->seg_hovered = near_segment;
    return 1;
  }
  if(inside)
  {
    mask_gui->form_selected = TRUE;
    if(post_select_cb) post_select_cb(mask_gui, inside, inside_border, inside_source, user_data);
    return 1;
  }
 
  // Deselection needs a refresh at least once.
  return need_refresh_anyway;
}
 
dt_masks_form_t *dt_masks_dup_masks_form(const dt_masks_form_t *mask_form)
{
  if (IS_NULL_PTR(mask_form)) return NULL;
 
  dt_masks_form_t *duplicate_form = malloc(sizeof(struct dt_masks_form_t));
  memcpy(duplicate_form, mask_form, sizeof(struct dt_masks_form_t));
 
  // Duplicate the GList *points payloads into a new list.
  GList *duplicated_points = NULL;
 
  if(mask_form->points)
  {
    const int point_struct_size = (mask_form->functions) ? mask_form->functions->point_struct_size : 0;
 
    if(point_struct_size != 0)
    {
      for(GList *point_node = mask_form->points; point_node; point_node = g_list_next(point_node))
      {
        void *point_copy = malloc(point_struct_size);
        memcpy(point_copy, point_node->data, point_struct_size);
        duplicated_points = g_list_prepend(duplicated_points, point_copy);
      }
    }
  }
 
  // The list was built in reverse order, so un-reverse it.
  duplicate_form->points = g_list_reverse(duplicated_points);
 
  return duplicate_form;
}
 
static void *_dup_masks_form_cb(const void *formdata, gpointer user_data)
{
  // Duplicate the main form struct, optionally substituting the provided override form.
  dt_masks_form_t *source_form = (dt_masks_form_t *)formdata;
  dt_masks_form_t *override_form = (dt_masks_form_t *)user_data;
  const dt_masks_form_t *form_to_copy
      = (IS_NULL_PTR(override_form) || source_form->formid != override_form->formid) ? source_form : override_form;
  return (void *)dt_masks_dup_masks_form(form_to_copy);
}
 
static inline dt_masks_form_group_t *_masks_group_find_form(dt_masks_form_t *group_form, const int form_id)
{
  if(IS_NULL_PTR(group_form) || !(group_form->type & DT_MASKS_GROUP)) return NULL;
 
  // Iterate group entries to find the matching form id.
  for(GList *group_node = group_form->points; group_node; group_node = g_list_next(group_node))
  {
    dt_masks_form_group_t *group_entry = (dt_masks_form_group_t *)group_node->data;
    if(group_entry && group_entry->formid == form_id) return group_entry;
  }
  return NULL;
}
 
int dt_masks_group_index_from_formid(const dt_masks_form_t *group_form, int form_id)
{
  if(IS_NULL_PTR(group_form) || !(group_form->type & DT_MASKS_GROUP)) return -1;
 
  int index = 0;
  for(const GList *group_node = group_form->points; group_node; group_node = g_list_next(group_node))
  {
    const dt_masks_form_group_t *group_entry = (const dt_masks_form_group_t *)group_node->data;
    if(!IS_NULL_PTR(group_entry) && group_entry->formid == form_id) return index;
    index++;
  }
  return -1;
}
 
dt_masks_form_t *dt_masks_get_visible_form(const dt_develop_t *dev)
{
  if(IS_NULL_PTR(dev) || IS_NULL_PTR(dev->form_gui)) return NULL;
  return dev->form_gui->form_visible;
}
 
void dt_masks_set_visible_form(dt_develop_t *dev, dt_masks_form_t *form)
{
  if(IS_NULL_PTR(dev) || IS_NULL_PTR(dev->form_gui)) return;
  dev->form_gui->form_visible = form;
}
 
void dt_masks_gui_init(dt_develop_t *dev)
{
  if(IS_NULL_PTR(dev)) return;
 
  if(IS_NULL_PTR(dev->form_gui))
  {
    dev->form_gui = (dt_masks_form_gui_t *)calloc(1, sizeof(dt_masks_form_gui_t));
    dt_masks_init_form_gui(dev->form_gui);
  }
 
  dt_masks_clear_form_gui(dev);
  dt_masks_set_visible_form(dev, NULL);
  dev->form_gui->pipe_hash = DT_PIXELPIPE_CACHE_HASH_INVALID;
  dev->form_gui->formid = 0;
}
 
void dt_masks_gui_cleanup(dt_develop_t *dev)
{
  if(IS_NULL_PTR(dev) || IS_NULL_PTR(dev->form_gui)) return;
 
  // If shutdown happens while a shape is being created, release the unfinished
  // temporary visible form before clearing the GUI state.
  dt_masks_form_exit_creation(NULL, dev->form_gui);
  
  dt_masks_clear_form_gui(dev);
  dt_free(dev->form_gui);
  dt_masks_set_visible_form(dev, NULL);
}
 
void dt_masks_gui_set_dragging(dt_masks_form_gui_t *gui)
{
  if(IS_NULL_PTR(gui)) return;
 
  if(gui->handle_selected && gui->handle_hovered >= 0) gui->handle_dragging = gui->handle_hovered;
  if(gui->handle_border_selected && gui->handle_border_hovered >= 0) gui->handle_border_dragging = gui->handle_border_hovered;
  if(gui->node_selected && gui->node_hovered >= 0) gui->node_dragging = gui->node_hovered;
  if(gui->seg_selected && gui->seg_hovered >= 0) gui->seg_dragging = gui->seg_hovered;
  if(gui->source_selected)
    gui->source_dragging = TRUE;
  else if(gui->form_selected)
    gui->form_dragging = TRUE;
}
 
void dt_masks_gui_reset_dragging(dt_masks_form_gui_t *gui)
{
  if(IS_NULL_PTR(gui)) return;
 
  gui->handle_dragging = -1;
  gui->handle_border_dragging = -1;
  gui->node_dragging = -1;
  gui->seg_dragging = -1;
  gui->form_dragging = FALSE;
  gui->source_dragging = FALSE;
}
 
gboolean dt_masks_gui_is_dragging(const dt_masks_form_gui_t *gui)
{
  if(IS_NULL_PTR(gui)) return FALSE;
  const gboolean dragging = (gui->form_dragging || gui->source_dragging || gui->seg_dragging >= 0 || gui->node_dragging >= 0
                              || gui->handle_dragging >= 0 || gui->handle_border_dragging >= 0);
  darktable.gui->mouse.is_dragging = dragging;
  return dragging;
}
 
dt_masks_form_group_t *dt_masks_form_group_from_parentid(int parent_id, int form_id)
{
  dt_masks_form_t *group_form = dt_masks_get_from_id(darktable.develop, parent_id);
  if(IS_NULL_PTR(group_form) || !(group_form->type & DT_MASKS_GROUP)) return NULL;
  return _masks_group_find_form(group_form, form_id);
}
 
dt_masks_form_group_t *dt_masks_form_get_selected_group(const dt_masks_form_t *mask_form,
                                                        const dt_masks_form_gui_t *mask_gui)
{
  if(IS_NULL_PTR(mask_form) || IS_NULL_PTR(mask_gui)) return NULL;
  if(mask_gui->group_selected < 0) return NULL;
  return (dt_masks_form_group_t *)g_list_nth_data(mask_form->points, mask_gui->group_selected);
}
 
dt_masks_form_group_t *dt_masks_form_get_selected_group_live(const dt_masks_form_t *mask_form,
                                                             const dt_masks_form_gui_t *mask_gui)
{
  if(IS_NULL_PTR(mask_form) || IS_NULL_PTR(mask_gui)) return NULL;
 
  dt_masks_form_group_t *selected_group_entry = NULL;
  if(mask_gui->group_selected >= 0)
    selected_group_entry = dt_masks_form_get_selected_group(mask_form, mask_gui);
 
  if(IS_NULL_PTR(selected_group_entry)) return NULL;
 
  if(selected_group_entry->parentid > 0)
  {
    // Re-resolve via parentid to ensure the pointer is still current.
    dt_masks_form_group_t *resolved_group_entry
        = dt_masks_form_group_from_parentid(selected_group_entry->parentid, selected_group_entry->formid);
    if(resolved_group_entry) return resolved_group_entry;
  }
 
  return selected_group_entry;
}
 
static dt_masks_form_t *_dt_masks_events_get_dispatch_form(dt_masks_form_t *visible_form,
                                                           const dt_masks_form_gui_t *mask_gui,
                                                           dt_masks_form_group_t **group_entry,
                                                           int *parent_id, int *form_index)
{
  if(group_entry) *group_entry = NULL;
  if(parent_id) *parent_id = 0;
  if(form_index) *form_index = 0;
 
  if(IS_NULL_PTR(visible_form)) return NULL;
  if(!(visible_form->type & DT_MASKS_GROUP)) return visible_form;
 
  dt_masks_form_group_t *selected_group_entry
      = dt_masks_form_get_selected_group_live(visible_form, mask_gui);
  if(IS_NULL_PTR(selected_group_entry)) return NULL;
 
  dt_masks_form_t *selected_form = dt_masks_get_from_id(darktable.develop, selected_group_entry->formid);
  if(IS_NULL_PTR(selected_form)) return NULL;
 
  if(group_entry) *group_entry = selected_group_entry;
  if(parent_id) *parent_id = selected_group_entry->parentid;
  if(form_index) *form_index = mask_gui->group_selected;
 
  return selected_form;
}
 
static gboolean _dt_masks_events_group_update_selection(dt_masks_form_t *group_form,
                                                        dt_masks_form_gui_t *mask_gui)
{
  if(IS_NULL_PTR(group_form) || IS_NULL_PTR(mask_gui)) return FALSE;
 
  dt_develop_t *const dev = darktable.develop;
  const float radius = DT_GUI_MOUSE_EFFECT_RADIUS;
  const float cursor_x = mask_gui->pos[0];
  const float cursor_y = mask_gui->pos[1];
  const int prev_group_selected = mask_gui->group_selected;
  const gboolean prev_border_selected = mask_gui->border_selected;
  int locked_formid = -1;
 
  if(dt_masks_is_anything_hovered(mask_gui))
    return TRUE;
 
  if(prev_border_selected && prev_group_selected >= 0)
  {
    dt_masks_form_group_t *selected_group_entry = dt_masks_form_get_selected_group_live(group_form, mask_gui);
    dt_masks_form_t *selected_form = selected_group_entry
                                         ? dt_masks_get_from_id(dev, selected_group_entry->formid)
                                         : NULL;
    const gboolean has_border_lock_candidate = selected_group_entry
                                               && selected_form
                                               && (selected_form->type & DT_MASKS_IS_CLOSED_SHAPE)
                                               && selected_form->functions
                                               && selected_form->functions->get_distance;
    if(has_border_lock_candidate)
    {
      // Lock selection only when the click lands on the selected closed-shape border/segment.
      int inside = 0;
      int inside_border = 0;
      int near = -1;
      int inside_source = 0;
      float dist = FLT_MAX;
      selected_form->functions->get_distance(cursor_x, cursor_y, radius, mask_gui, prev_group_selected,
                                             g_list_length(selected_form->points), &inside, &inside_border,
                                             &near, &inside_source, &dist);
      if(inside_border || near >= 0)
        locked_formid = selected_group_entry->formid;
    }
  }
 
  if(prev_group_selected >= 0)
    dt_masks_soft_reset_form_gui(mask_gui);
 
  dt_masks_form_t *selected_form = NULL;
  int selected_index = -1;
  float best_dist = FLT_MAX;
 
  int index = 0;
  for(GList *group_node = group_form->points; group_node; group_node = g_list_next(group_node), index++)
  {
    dt_masks_form_group_t *group_entry = (dt_masks_form_group_t *)group_node->data;
    if(IS_NULL_PTR(group_entry)) continue;
    if(locked_formid >= 0 && group_entry->formid != locked_formid) continue;
 
    dt_masks_form_t *form = dt_masks_get_from_id(dev, group_entry->formid);
    if(IS_NULL_PTR(form)) continue;
 
    int inside = 0;
    int inside_border = 0;
    int near = -1;
    int inside_source = 0;
    float dist = FLT_MAX;
    if(form->functions && form->functions->get_distance)
      form->functions->get_distance(cursor_x, cursor_y, radius, mask_gui, index, g_list_length(form->points),
                                    &inside, &inside_border, &near, &inside_source, &dist);
 
    const gboolean is_selected_form = (prev_group_selected == index);
    const gboolean hit_border = (inside_border || near >= 0);
    const gboolean is_open_shape = (form->type & DT_MASKS_IS_OPEN_SHAPE) != 0;
    // Only open shapes can be selected via their border when unselected.
    if(!is_selected_form && hit_border && !is_open_shape)
      continue;
 
    if(inside || hit_border || inside_source)
    {
      const float dx = mask_gui->raw_pos[0] - form->gravity_center[0];
      const float dy = mask_gui->raw_pos[1] - form->gravity_center[1];
      const float center_dist2 = dx * dx + dy * dy;
      const float combined_dist2 = dist * center_dist2;
      if(combined_dist2 < best_dist)
      {
        selected_form = form;
        selected_index = index;
        best_dist = combined_dist2;
      }
    }
  }
 
  if(!IS_NULL_PTR(selected_form))
  {
    mask_gui->group_selected = selected_index;
    return TRUE;
  }
 
  return mask_gui->group_selected >= 0;
}
 
static gboolean _dt_masks_events_should_update_hover_on_move(dt_masks_form_gui_t *mask_gui)
{
  if(IS_NULL_PTR(mask_gui) || mask_gui->creation) return FALSE;
  if(mask_gui->form_rotating || mask_gui->border_toggling || mask_gui->gradient_toggling) return FALSE;
  if(dt_masks_gui_is_dragging(mask_gui)) return FALSE;
  return dt_masks_gui_should_hit_test(mask_gui);
}
 
static int _dt_masks_events_update_hover(dt_masks_form_t *dispatch_form, dt_masks_form_gui_t *mask_gui,
                                          const int form_index)
{
  if(IS_NULL_PTR(dispatch_form) || IS_NULL_PTR(mask_gui) || !dispatch_form->functions || !dispatch_form->functions->update_hover)
    return 0;
  return dispatch_form->functions->update_hover(dispatch_form, mask_gui, form_index);
}
 
static gboolean _dt_masks_events_cursor_over_form(const dt_masks_form_t *dispatch_form,
                                                  dt_masks_form_gui_t *mask_gui,
                                                  const int form_index)
{
  if(!dispatch_form || IS_NULL_PTR(mask_gui) || !dispatch_form->functions || !dispatch_form->functions->get_distance)
    return FALSE;
 
  int inside = 0;
  int inside_border = 0;
  int near = -1;
  int inside_source = 0;
  float dist = FLT_MAX;
  dispatch_form->functions->get_distance(mask_gui->pos[0], mask_gui->pos[1], DT_GUI_MOUSE_EFFECT_RADIUS,
                                         mask_gui, form_index,
                                         g_list_length(dispatch_form->points), &inside, &inside_border, &near,
                                         &inside_source, &dist);
  return inside || inside_border || near >= 0 || inside_source;
}
 
static gboolean _dt_masks_events_group_blocks_motion(dt_masks_form_gui_t *mask_gui)
{
  if(IS_NULL_PTR(mask_gui)) return FALSE;
 
  const float radius = DT_GUI_MOUSE_EFFECT_RADIUS;
  if(mask_gui->scrollx == 0.0f || mask_gui->scrolly == 0.0f) return FALSE;
 
  if((mask_gui->scrollx - mask_gui->pos[0] < radius && mask_gui->scrollx - mask_gui->pos[0] > -radius)
     && (mask_gui->scrolly - mask_gui->pos[1] < radius && mask_gui->scrolly - mask_gui->pos[1] > -radius))
    return TRUE;
 
  mask_gui->scrollx = 0.0f;
  mask_gui->scrolly = 0.0f;
  return FALSE;
}
 
static gboolean _dt_masks_events_flush_rebuild_if_needed(struct dt_iop_module_t *module,
                                                         dt_masks_form_t *dispatch_form,
                                                         dt_masks_form_gui_t *mask_gui,
                                                         const int form_index, const int button)
{
  if(button != 1) return FALSE;
  if(!dt_masks_gui_is_dragging(mask_gui)) return FALSE;
 
  if(mask_gui->rebuild_pending)
  {
    if(!IS_NULL_PTR(dispatch_form))
    {
      dt_masks_gui_form_create(dispatch_form, mask_gui, form_index, module);
 
      dt_develop_t *const dev = darktable.develop;
      if(!IS_NULL_PTR(dev))
      {
        mask_gui->last_rebuild_ts = dt_get_wtime();
        mask_gui->last_rebuild_pos[0] = mask_gui->pos[0];
        mask_gui->last_rebuild_pos[1] = mask_gui->pos[1];
      }
    }
    mask_gui->rebuild_pending = FALSE;
  }
 
  return TRUE;
}
 
GList *dt_masks_dup_forms_deep(GList *form_list, dt_masks_form_t *replacement_form)
{
  return (GList *)g_list_copy_deep(form_list, _dup_masks_form_cb, (gpointer)replacement_form);
}
 
static gboolean _set_hinter_message(dt_masks_form_gui_t *mask_gui, const dt_masks_form_t *mask_form)
{
  char message[256] = "";
 
  const int form_type = mask_form->type;
 
  int opacity_percent = 100;
 
  const dt_masks_form_t *selected_form = mask_form;
  int selected_form_id = 0;
  if(!IS_NULL_PTR(mask_form) && (mask_form->type & DT_MASKS_GROUP))
  {
    const dt_masks_form_group_t *selected_group_entry
        = dt_masks_form_get_selected_group_live(mask_form, mask_gui);
    if(!IS_NULL_PTR(selected_group_entry)) selected_form_id = selected_group_entry->formid;
  }
 
  dt_print(DT_DEBUG_INPUT,
           "[masks] hint begin: form=%p type=%d gui=%p group_selected=%d form_selected=%d node_hovered=%d seg_hovered=%d selected_formid=%d\n",
           (void *)mask_form, mask_form ? mask_form->type : -1, (void *)mask_gui,
           mask_gui->group_selected, mask_gui->form_selected,
           mask_gui->node_hovered, mask_gui->seg_hovered,
           selected_form_id);
  if(form_type & DT_MASKS_GROUP)
  {
    // Resolve the selected form inside a group (if any).
    dt_masks_form_group_t *selected_group_entry = dt_masks_form_get_selected_group_live(mask_form, mask_gui);
    if(!IS_NULL_PTR(selected_group_entry))
    {
      opacity_percent
          = dt_masks_form_get_interaction_value(selected_group_entry, DT_MASKS_INTERACTION_OPACITY) * 100.f;
      selected_form = dt_masks_get_from_id(darktable.develop, selected_group_entry->formid);
      if(IS_NULL_PTR(selected_form)) return FALSE;
    }
  }
  else
  {
    opacity_percent = (int)(dt_conf_get_float("plugins/darkroom/masks/opacity") * 100);
  }
 
  if(selected_form->functions && selected_form->functions->set_hint_message)
  {
    selected_form->functions->set_hint_message(mask_gui, selected_form, opacity_percent, message, sizeof(message));
  }
 
  dt_control_hinter_message(darktable.control, message);
  dt_print(DT_DEBUG_INPUT,
           "[masks] hint end: sel=%p has_set_hint=%d opacity=%d msg_len=%" G_GSIZE_FORMAT " msg='%s'\n",
           (void *)selected_form,
           (selected_form && selected_form->functions && selected_form->functions->set_hint_message) ? 1 : 0,
           opacity_percent, strlen(message), message);
  return message[0] != '\0';
}
 
void dt_masks_init_form_gui(dt_masks_form_gui_t *mask_gui)
{
  memset(mask_gui, 0, sizeof(dt_masks_form_gui_t));
 
  mask_gui->pos[0] = mask_gui->pos[1] = -1.0f;
  mask_gui->rel_pos[0] = mask_gui->rel_pos[1] = -1.0f;
  mask_gui->raw_pos[0] = mask_gui->raw_pos[1] = -1.0f;
  mask_gui->pos_source[0] = mask_gui->pos_source[1] = -1.0f;
  mask_gui->source_pos_type = DT_MASKS_SOURCE_POS_RELATIVE_TEMP;
  mask_gui->node_hovered = -1;
  mask_gui->handle_hovered = -1;
  mask_gui->seg_hovered = -1;
  mask_gui->handle_border_hovered = -1;
  mask_gui->node_selected = FALSE;
  mask_gui->handle_selected = FALSE;
  mask_gui->seg_selected = FALSE;
  mask_gui->handle_border_selected = FALSE;
  mask_gui->node_selected_idx = -1;
  mask_gui->form_selected = FALSE;
  mask_gui->border_selected = FALSE;
  mask_gui->source_selected = FALSE;
  mask_gui->pivot_selected = FALSE;
  mask_gui->last_rebuild_ts = 0.0;
  mask_gui->last_rebuild_pos[0] = mask_gui->last_rebuild_pos[1] = 0.0f;
  mask_gui->rebuild_pending = FALSE;
  mask_gui->last_hit_test_pos[0] = mask_gui->last_hit_test_pos[1] = -1.0f;
}
 
void dt_masks_soft_reset_form_gui(dt_masks_form_gui_t *mask_gui)
{
  // Note: we have an hard reset function below that frees all buffers and such
  mask_gui->source_selected = FALSE;
  mask_gui->node_hovered = -1;
  mask_gui->handle_hovered = -1;
  mask_gui->seg_hovered = -1;
  mask_gui->handle_border_hovered = -1;
  mask_gui->node_selected = FALSE;
  mask_gui->handle_selected = FALSE;
  mask_gui->seg_selected = FALSE;
  mask_gui->handle_border_selected = FALSE;
  mask_gui->node_selected_idx = -1;
  mask_gui->group_selected = -1;
  mask_gui->delta[0] = mask_gui->delta[1] = 0.0f;
  mask_gui->form_selected = mask_gui->border_selected = mask_gui->form_dragging = mask_gui->form_rotating = FALSE;
  mask_gui->pivot_selected = FALSE;
  mask_gui->handle_border_dragging = mask_gui->seg_dragging = mask_gui->handle_dragging = mask_gui->node_dragging = -1;
  mask_gui->last_rebuild_ts = 0.0;
  mask_gui->last_rebuild_pos[0] = mask_gui->last_rebuild_pos[1] = 0.0f;
  mask_gui->rebuild_pending = FALSE;
  mask_gui->last_hit_test_pos[0] = mask_gui->last_hit_test_pos[1] = -1.0f;
}
 
void dt_masks_gui_form_create(dt_masks_form_t *mask_form, dt_masks_form_gui_t *mask_gui,
                              int form_index, dt_iop_module_t *module)
{
  const int gui_points_count = g_list_length(mask_gui->points);
  if(gui_points_count == form_index)
  {
    dt_masks_form_gui_points_t *gui_points_new
        = (dt_masks_form_gui_points_t *)calloc(1, sizeof(dt_masks_form_gui_points_t));
    mask_gui->points = g_list_append(mask_gui->points, gui_points_new);
  }
  else if(gui_points_count < form_index)
    return;
 
  dt_masks_gui_form_remove(mask_form, mask_gui, form_index);
 
  dt_masks_form_gui_points_t *gui_points
      = (dt_masks_form_gui_points_t *)g_list_nth_data(mask_gui->points, form_index);
  if(dt_masks_get_points_border(darktable.develop, mask_form, &gui_points->points, &gui_points->points_count,
                                &gui_points->border, &gui_points->border_count, 0, NULL) == 0)
  {
    if(mask_form->type & DT_MASKS_CLONE)
    {
      if(dt_masks_get_points_border(darktable.develop, mask_form, &gui_points->source, &gui_points->source_count,
                                    NULL, NULL, TRUE, module)
         != 0)
        return;
    }
    mask_gui->pipe_hash = dt_dev_backbuf_get_hash(&darktable.develop->preview_pipe->backbuf);
    mask_gui->formid = mask_form->formid;
    mask_gui->type = mask_form->type;
 
  }
 
  dt_masks_form_update_gravity_center(mask_form);
}
 
gboolean dt_masks_gui_form_create_throttled(dt_masks_form_t *mask_form, dt_masks_form_gui_t *mask_gui,
                                            int form_index, dt_iop_module_t *module,
                                            float posx, float posy)
{
  if(IS_NULL_PTR(mask_form) || IS_NULL_PTR(mask_gui)) return FALSE;
 
  dt_develop_t *const develop = darktable.develop;
  if(IS_NULL_PTR(develop))
  {
    dt_masks_gui_form_create(mask_form, mask_gui, form_index, module);
    return TRUE;
  }
 
  const double now = dt_get_wtime();
  const double min_delta_time = 1.0 / 60.0;
  const float min_dist2 = 4.0f;
  const gboolean force_rebuild
      = (develop->preview_pipe
         && mask_gui->pipe_hash != dt_dev_backbuf_get_hash(&develop->preview_pipe->backbuf));
 
  if(!force_rebuild && mask_gui->last_rebuild_ts > 0.0)
  {
    const double elapsed_time = now - mask_gui->last_rebuild_ts;
    const float delta_x = posx - mask_gui->last_rebuild_pos[0];
    const float delta_y = posy - mask_gui->last_rebuild_pos[1];
    if(elapsed_time < min_delta_time && (delta_x * delta_x + delta_y * delta_y) < min_dist2)
    {
      mask_gui->rebuild_pending = TRUE;
      return FALSE;
    }
  }
 
  dt_masks_gui_form_create(mask_form, mask_gui, form_index, module);
  mask_gui->last_rebuild_ts = now;
  mask_gui->last_rebuild_pos[0] = posx;
  mask_gui->last_rebuild_pos[1] = posy;
  mask_gui->rebuild_pending = FALSE;
  return TRUE;
}
 
void dt_masks_form_gui_points_free(gpointer data)
{
  if(IS_NULL_PTR(data)) return;
 
  dt_masks_form_gui_points_t *gui_points = (dt_masks_form_gui_points_t *)data;
 
  dt_pixelpipe_cache_free_align(gui_points->points);
  dt_pixelpipe_cache_free_align(gui_points->border);
  dt_pixelpipe_cache_free_align(gui_points->source);
  dt_free(gui_points);
}
 
void dt_masks_remove_node(struct dt_iop_module_t *module, dt_masks_form_t *mask_form, int parent_id,
                          dt_masks_form_gui_t *mask_gui, int form_index, int node_index)
{
  if(IS_NULL_PTR(mask_form) || IS_NULL_PTR(mask_form->points)) return;
  dt_masks_node_brush_t *brush_node = (dt_masks_node_brush_t *)g_list_nth_data(mask_form->points, node_index);
  if(IS_NULL_PTR(brush_node)) return;
  mask_form->points = g_list_remove(mask_form->points, brush_node);
  dt_free(brush_node);
  mask_gui->node_hovered = -1;
  mask_gui->node_selected = FALSE;
  mask_gui->node_selected_idx = -1;
  if(mask_form->functions && mask_form->functions->init_ctrl_points)
    mask_form->functions->init_ctrl_points(mask_form);
    
  // we recreate the form points
  dt_masks_gui_form_create(mask_form, mask_gui, form_index, module);
}
 
static gboolean _masks_remove_shape(struct dt_iop_module_t *module, dt_masks_form_t *mask_form, int parent_id,
                                    dt_masks_form_gui_t *mask_gui, int form_index)
{
  // if the form doesn't below to a group, we don't delete it
  if(parent_id <= 0) return 1;
 
  // we hide the form
  dt_masks_form_t *visible_form = dt_masks_get_visible_form(darktable.develop);
  if(IS_NULL_PTR(visible_form) || !(visible_form->type & DT_MASKS_GROUP))
    dt_masks_change_form_gui(NULL);
  else if(g_list_shorter_than(visible_form->points, 2))
    dt_masks_change_form_gui(NULL);
  else
  {
    const int edit_mode = mask_gui->edit_mode;
 
    dt_masks_clear_form_gui(darktable.develop);
    // Remove the selected shape copy from the visible group before deleting the
    // real group entry below.
    for(GList *forms = visible_form->points; forms; forms = g_list_next(forms))
    {
      dt_masks_form_group_t *group_entry = (dt_masks_form_group_t *)forms->data;
      if(group_entry->formid == mask_form->formid)
      {
        visible_form->points = g_list_remove(visible_form->points, group_entry);
        dt_free(group_entry);
        break;
      }
    }
    mask_gui->edit_mode = edit_mode;
  }
 
  // we delete or remove the shape
  // Called from node removal, if there was not enough nodes to keep the whole shape,
  // that's how this was called:
  // dt_masks_form_remove(module, NULL, form);
  // Called from shape removal, this is how it was called:
  dt_masks_form_delete(module, dt_masks_get_from_id(darktable.develop, parent_id), mask_form);
  // Not sure what difference it makes.
 
  return 1;
}
 
static int _masks_gui_form_group_use_count(const dt_develop_t *dev, const int formid)
{
  if(IS_NULL_PTR(dev)) return 0;
 
  int count = 0;
  for(GList *form_node = dev->forms; form_node; form_node = g_list_next(form_node))
  {
    dt_masks_form_t *group_form = (dt_masks_form_t *)form_node->data;
    if(IS_NULL_PTR(group_form) || !(group_form->type & DT_MASKS_GROUP)) continue;
 
    for(GList *group_node = group_form->points; group_node; group_node = g_list_next(group_node))
    {
      dt_masks_form_group_t *group_entry = (dt_masks_form_group_t *)group_node->data;
      if(group_entry && group_entry->formid == formid)
      {
        count++;
        if(count > 1) goto done;
        break;
      }
    }
  }
 
done:
  return count;
}
 
gboolean dt_masks_remove_or_delete(struct dt_iop_module_t *module, dt_masks_form_t *sel, int parent_id,
                                    dt_masks_form_gui_t *mask_gui, int form_id)
{
  const int use_count = _masks_gui_form_group_use_count(darktable.develop, form_id);
  
  // We don't ask for confirmation if the module uses internal masks,
  // just delete the form as it won't be visible in the shape manager.
  const gboolean internal_masks
      = !IS_NULL_PTR(module)
        && ((module->flags() & IOP_FLAGS_INTERNAL_MASKS) == IOP_FLAGS_INTERNAL_MASKS);
 
  int response = GTK_RESPONSE_YES;
  if(use_count <= 1 && !internal_masks)
  {
    response = dt_masks_gui_confirm_delete_form_dialog(sel->name);
    if(response == GTK_RESPONSE_CANCEL) return FALSE;
  }
 
  dt_masks_form_t *visible_form = dt_masks_get_visible_form(darktable.develop);
  int next_form_index = -1;
  int next_formid = 0;
  if(!IS_NULL_PTR(visible_form) && (visible_form->type & DT_MASKS_GROUP)
     && mask_gui->group_selected >= 0 && !g_list_shorter_than(visible_form->points, 2))
  {
    const int group_length = g_list_length(visible_form->points);
    next_form_index = mask_gui->group_selected < group_length - 1
                          ? mask_gui->group_selected
                          : mask_gui->group_selected - 1;
 
    // Walk from the selected row to remember the shape that should be selected
    // after deletion: next row first, previous row if the removed row is last.
    GList *selected_node = g_list_nth(visible_form->points, mask_gui->group_selected);
    if(!IS_NULL_PTR(selected_node))
    {
      GList *next_node = g_list_next(selected_node);
      if(IS_NULL_PTR(next_node)) next_node = g_list_previous(selected_node);
      if(!IS_NULL_PTR(next_node))
      {
        dt_masks_form_group_t *next_group_entry = (dt_masks_form_group_t *)next_node->data;
        if(!IS_NULL_PTR(next_group_entry)) next_formid = next_group_entry->formid;
      }
    }
  }
 
  gboolean res = TRUE;
  int signal_parent_id = 0;
  dt_masks_event_t signal_event = DT_MASKS_EVENT_REMOVE;
 
  if(response == GTK_RESPONSE_NO)
  {
    // Only remove from current group, keep the form itself for potential reuse.
    res = _masks_remove_shape(module, sel, parent_id, mask_gui, mask_gui->group_selected);
    signal_parent_id = parent_id;
    signal_event = DT_MASKS_EVENT_DELETE;
  }
 
  else // Default if use count > 1, or responded YES.
  {
    if(IS_NULL_PTR(visible_form) || !(visible_form->type & DT_MASKS_GROUP))
      dt_masks_change_form_gui(NULL);
    else if(g_list_shorter_than(visible_form->points, 2))
      dt_masks_change_form_gui(NULL);
    else
    {
      const int edit_mode = mask_gui->edit_mode;
      dt_masks_clear_form_gui(darktable.develop);
      // Remove the selected shape copy from the visible group before deleting
      // the real form from the develop mask list below.
      for(GList *forms = visible_form->points; forms; forms = g_list_next(forms))
      {
        dt_masks_form_group_t *group_entry = (dt_masks_form_group_t *)forms->data;
        if(group_entry->formid == sel->formid)
        {
          visible_form->points = g_list_remove(visible_form->points, group_entry);
          dt_free(group_entry);
          break;
        }
      }
      mask_gui->edit_mode = edit_mode;
      if(next_formid > 0)
      {
        mask_gui->group_selected = next_form_index;
        mask_gui->form_selected = TRUE;
      }
    }
 
    dt_masks_form_delete(module, NULL, sel);
  }
 
  dt_dev_add_history_item(darktable.develop, module, TRUE, TRUE);
  DT_DEBUG_CONTROL_SIGNAL_RAISE(darktable.signals, DT_SIGNAL_MASK_CHANGED, form_id, signal_parent_id,
                                signal_event);
 
  if(res && next_formid > 0)
  {
    // The mask manager rebuilds its tree on the delete/remove signal, so apply
    // the replacement selection after the signal has finished refreshing lists.
    mask_gui->group_selected = next_form_index;
    mask_gui->form_selected = TRUE;
    dt_dev_masks_selection_change(darktable.develop, module, next_formid, FALSE);
    dt_masks_select_form(module, dt_masks_get_from_id(darktable.develop, next_formid));
  }
  return res;
}
 
gboolean dt_masks_form_exit_creation(dt_iop_module_t *module, dt_masks_form_gui_t *mask_gui)
{
  if(IS_NULL_PTR(mask_gui)) return FALSE;
 
  if(mask_gui->creation)
  {
    const int last_formid = mask_gui->creation_last_formid;
    dt_iop_module_t *creation_module = mask_gui->creation_module ? mask_gui->creation_module : module;
    dt_masks_form_t *temporary_form = dt_masks_get_visible_form(darktable.develop);
 
    if(mask_gui->guipoints)
    {
      dt_masks_dynbuf_free(mask_gui->guipoints);
      dt_masks_dynbuf_free(mask_gui->guipoints_payload);
      mask_gui->guipoints = NULL;
      mask_gui->guipoints_payload = NULL;
      mask_gui->guipoints_count = 0;
    }
 
    // The visible form is the current unfinished shape while creation is active.
    // If it was never appended to develop->forms, drop it before selecting the
    // last completed shape from this creation session.
    if(!IS_NULL_PTR(temporary_form) && IS_NULL_PTR(dt_masks_get_from_id(darktable.develop, temporary_form->formid)))
    {
      dt_masks_set_visible_form(darktable.develop, NULL);
      dt_masks_free_form(temporary_form);
    }
 
    dt_masks_creation_mode_quit(mask_gui);
    g_list_free(mask_gui->creation_formids);
    mask_gui->creation_formids = NULL;
    mask_gui->creation_last_formid = 0;
    mask_gui->creation_type = DT_MASKS_NONE;
    mask_gui->creation_module = NULL;
 
    if(!IS_NULL_PTR(creation_module))
    {
      dt_masks_set_edit_mode(creation_module, DT_MASKS_EDIT_FULL);
      if(last_formid > 0)
      {
        // Keep the shape manager selection in sync without letting its selection
        // handler replace the visible module group with the standalone shape.
        dt_dev_masks_selection_change(darktable.develop, creation_module, last_formid, FALSE);
      }
 
      dt_masks_iop_update(creation_module);
      dt_iop_gui_blend_data_t *blend_data = (dt_iop_gui_blend_data_t *)creation_module->blend_data;
      if(!IS_NULL_PTR(darktable.develop) && !IS_NULL_PTR(darktable.develop->form_gui))
        darktable.develop->form_gui->edit_mode = DT_MASKS_EDIT_FULL;
      if(!IS_NULL_PTR(blend_data) && GTK_IS_TOGGLE_BUTTON(blend_data->masks_edit))
      {
        // Creation mode keeps the edit button visually inactive while a shape
        // type button owns the interaction. Once creation is exited, restore both
        // the module edit state and the visible toggle explicitly.
        blend_data->masks_shown = DT_MASKS_EDIT_FULL;
        gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(blend_data->masks_edit), TRUE);
        gtk_widget_queue_draw(blend_data->masks_edit);
      }
 
      if(last_formid > 0 && !IS_NULL_PTR(darktable.develop) && !IS_NULL_PTR(darktable.develop->form_gui))
      {
        dt_masks_form_gui_t *current_gui = darktable.develop->form_gui;
        dt_masks_form_t *visible_form = dt_masks_get_visible_form(darktable.develop);
        const int selected_index = dt_masks_group_index_from_formid(visible_form, last_formid);
        if(selected_index >= 0)
        {
          // The displayed overlay is the module group; select the last completed
          // form inside that group once creation is closed.
          current_gui->group_selected = selected_index;
          current_gui->form_selected = TRUE;
          // reset other variables
          current_gui->border_selected = FALSE;
          current_gui->source_selected = FALSE;
          current_gui->node_selected = FALSE;
          current_gui->handle_selected = FALSE;
          current_gui->seg_selected = FALSE;
          current_gui->handle_border_selected = FALSE;
          current_gui->node_selected_idx = -1;
          current_gui->form_dragging = FALSE;
          current_gui->source_dragging = FALSE;
          current_gui->form_rotating = FALSE;
          current_gui->pivot_selected = FALSE;
        }
      }
    }
    else if(last_formid > 0)
    {
      dt_masks_change_form_gui(dt_masks_get_from_id(darktable.develop, last_formid));
      dt_dev_masks_selection_change(darktable.develop, NULL, last_formid, TRUE);
      if(!IS_NULL_PTR(darktable.develop) && !IS_NULL_PTR(darktable.develop->form_gui))
      {
        // A standalone visible form is rendered at index 0.
        darktable.develop->form_gui->group_selected = 0;
        darktable.develop->form_gui->form_selected = TRUE;
      }
    }
    else
    {
      dt_masks_change_form_gui(NULL);
    }
 
    return TRUE;
  }
  return FALSE;
}
 
gboolean dt_masks_gui_remove(struct dt_iop_module_t *module, dt_masks_form_t *mask_form,
                             dt_masks_form_gui_t *mask_gui, const int parent_id)
{
  if(mask_gui->edit_mode != DT_MASKS_EDIT_FULL)
    return FALSE;
 
  // Just clean temp mask if we are in creation mode
  if(dt_masks_form_exit_creation(module, mask_gui))
    return TRUE;
 
  // we remove the selected node (and the entire form if there is too few nodes left)
  if(((mask_form->type & DT_MASKS_IS_PATH_SHAPE) != 0) && mask_gui->node_selected)
  {
    if(g_list_shorter_than(mask_form->points, 3))
      return _masks_remove_shape(module, mask_form, parent_id, mask_gui, mask_gui->group_selected);
 
    dt_masks_remove_node(module, mask_form, parent_id, mask_gui, mask_gui->group_selected,
                         mask_gui->node_hovered);
 
    return TRUE;
  }
  // we remove the entire shape
  else if(parent_id > 0)
  {
    dt_masks_remove_or_delete(module, mask_form, parent_id, mask_gui, mask_form->formid);
    return TRUE; // something happened even if the dialog was cancelled.
  }
  return FALSE;
}
 
void dt_masks_gui_form_remove(dt_masks_form_t *mask_form, dt_masks_form_gui_t *mask_gui, int form_index)
{
  dt_masks_form_gui_points_t *gui_points
      = (dt_masks_form_gui_points_t *)g_list_nth_data(mask_gui->points, form_index);
  mask_gui->pipe_hash = DT_PIXELPIPE_CACHE_HASH_INVALID;
  mask_gui->formid = 0;
 
  if(!IS_NULL_PTR(gui_points))
  {
    gui_points->points_count = gui_points->border_count = gui_points->source_count = 0;
    dt_pixelpipe_cache_free_align(gui_points->points);
    gui_points->points = NULL;
    dt_pixelpipe_cache_free_align(gui_points->border);
    gui_points->border = NULL;
    dt_pixelpipe_cache_free_align(gui_points->source);
    gui_points->source = NULL;
  }
}
 
void dt_masks_gui_form_test_create(dt_masks_form_t *mask_form, dt_masks_form_gui_t *mask_gui,
                                   dt_iop_module_t *module)
{
  // we test if the image has changed
  if(mask_gui->pipe_hash != DT_PIXELPIPE_CACHE_HASH_INVALID)
  {
    if(mask_gui->pipe_hash != dt_dev_backbuf_get_hash(&darktable.develop->preview_pipe->backbuf))
    {
      mask_gui->pipe_hash = DT_PIXELPIPE_CACHE_HASH_INVALID;
      mask_gui->formid = 0;
      g_list_free_full(mask_gui->points, dt_masks_form_gui_points_free);
      mask_gui->points = NULL;
    }
  }
 
  // we create the form if needed
  if(mask_gui->pipe_hash == DT_PIXELPIPE_CACHE_HASH_INVALID)
  {
    if(mask_form->type & DT_MASKS_GROUP)
    {
      int form_index = 0;
      for(GList *group_node = mask_form->points; group_node; group_node = g_list_next(group_node))
      {
        dt_masks_form_group_t *group_entry = (dt_masks_form_group_t *)group_node->data;
        dt_masks_form_t *child_form = dt_masks_get_from_id(darktable.develop, group_entry->formid);
        if(IS_NULL_PTR(child_form)) return;
        dt_masks_gui_form_create(child_form, mask_gui, form_index, module);
        form_index++;
      }
    }
    else
    {
      dt_masks_gui_form_create(mask_form, mask_gui, 0, module);
    }
  }
}
 
static void _check_id(dt_masks_form_t *mask_form)
{
  int new_form_id = 100;
  for(GList *form_node = darktable.develop->forms; form_node; )
  {
    dt_masks_form_t *existing_form = (dt_masks_form_t *)form_node->data;
    if(existing_form->formid == mask_form->formid)
    {
      mask_form->formid = new_form_id++;
      form_node = darktable.develop->forms; // jump back to start of list
    }
    else
    {
      form_node = g_list_next(form_node); // advance to next form
    }
  }
}
 
static void _set_group_name_from_module(dt_iop_module_t *module, dt_masks_form_t *group_form)
{
  gchar *group_name = dt_dev_get_masks_group_name(module);
  g_strlcpy(group_form->name, group_name, sizeof(group_form->name));
  dt_free(group_name);
}
 
static dt_masks_form_t *_group_create(dt_develop_t *develop, dt_iop_module_t *module, dt_masks_type_t group_type)
{
  dt_masks_form_t *group_form = dt_masks_create(group_type);
  _set_group_name_from_module(module, group_form);
  _check_id(group_form);
  dt_masks_append_form(develop, group_form);
  module->blend_params->mask_id = group_form->formid;
  return group_form;
}
 
// get the group form associated to the module, if any
static dt_masks_form_t *_group_from_module(dt_develop_t *develop, dt_iop_module_t *module)
{
  return dt_masks_get_from_id(develop, module->blend_params->mask_id);
}
 
void dt_masks_append_form(dt_develop_t *develop, dt_masks_form_t *mask_form)
{
  dt_pthread_rwlock_wrlock(&develop->masks_mutex);
  develop->forms = g_list_append(develop->forms, mask_form);
  dt_pthread_rwlock_unlock(&develop->masks_mutex);
}
 
void dt_masks_remove_form(dt_develop_t *develop, dt_masks_form_t *mask_form)
{
  dt_pthread_rwlock_wrlock(&develop->masks_mutex);
  develop->forms = g_list_remove(develop->forms, mask_form);
  dt_pthread_rwlock_unlock(&develop->masks_mutex);
}
 
void dt_masks_gui_form_save_creation(dt_develop_t *develop, dt_iop_module_t *module, dt_masks_form_t *mask_form,
                                     dt_masks_form_gui_t *mask_gui)
{
  // we check if the id is already registered
  _check_id(mask_form);
 
  // mask nb will be at least the length of the list
  guint form_count = 0;
 
  // count only the same forms to have a clean numbering
  dt_pthread_rwlock_rdlock(&develop->masks_mutex);
  for(GList *form_node = develop->forms; form_node; form_node = g_list_next(form_node))
  {
    dt_masks_form_t *existing_form = (dt_masks_form_t *)form_node->data;
    if(existing_form->type == mask_form->type) form_count++;
  }
  dt_pthread_rwlock_unlock(&develop->masks_mutex);
 
  gboolean name_exists = FALSE;
 
  // check that we do not have duplicate, in case some masks have been
  // removed we can have hole and so nb could already exists.
  do
  {
    name_exists = FALSE;
    form_count++;
 
    if(mask_form->functions && mask_form->functions->set_form_name)
      mask_form->functions->set_form_name(mask_form, form_count);
 
    dt_pthread_rwlock_rdlock(&develop->masks_mutex);
    for(GList *form_node = develop->forms; form_node; form_node = g_list_next(form_node))
    {
      dt_masks_form_t *existing_form = (dt_masks_form_t *)form_node->data;
      if(!strcmp(existing_form->name, mask_form->name))
      {
        name_exists = TRUE;
        break;
      }
    }
    dt_pthread_rwlock_unlock(&develop->masks_mutex);
 
  } while(name_exists);
 
  dt_masks_form_update_gravity_center(mask_form);
 
  dt_masks_form_group_t *group_entry = NULL;
  if(!IS_NULL_PTR(module))
  {
    group_entry = malloc(sizeof(dt_masks_form_group_t));
    if(IS_NULL_PTR(group_entry)) return;
  }
 
  dt_masks_append_form(develop, mask_form);
 
  if(!IS_NULL_PTR(module))
  {
    // is there already a masks group for this module ?
    dt_masks_form_t *group_form = _group_from_module(develop, module);
    if(IS_NULL_PTR(group_form))
    {
      // we create a new group
      if(mask_form->type & (DT_MASKS_CLONE | DT_MASKS_NON_CLONE))
        group_form = _group_create(develop, module, DT_MASKS_GROUP | DT_MASKS_CLONE);
      else
        group_form = _group_create(develop, module, DT_MASKS_GROUP);
    }
    // we add the form in this group
    group_entry->formid = mask_form->formid;
    group_entry->parentid = group_form->formid;
    group_entry->state = DT_MASKS_STATE_SHOW | DT_MASKS_STATE_USE | DT_MASKS_STATE_UNION;
    group_entry->opacity = dt_conf_get_float("plugins/darkroom/masks/opacity");
    group_form->points = g_list_append(group_form->points, group_entry);
    
    // we update module gui
      
    if(IS_NULL_PTR(mask_gui)) dt_masks_iop_update(module);
  }
 
  if(!IS_NULL_PTR(mask_gui))
  {
    mask_gui->creation_formids = g_list_append(mask_gui->creation_formids, GINT_TO_POINTER(mask_form->formid));
    mask_gui->creation_last_formid = mask_form->formid;
 
    if(!IS_NULL_PTR(module))
    {
      DT_DEBUG_CONTROL_SIGNAL_RAISE(darktable.signals, DT_SIGNAL_MASK_CHANGED, group_entry->formid,
                                    group_entry->parentid, DT_MASKS_EVENT_ADD);
    }
    else
    {
      DT_DEBUG_CONTROL_SIGNAL_RAISE(darktable.signals, DT_SIGNAL_MASK_CHANGED, mask_form->formid,
                                    0, DT_MASKS_EVENT_ADD);
    }
 
    // Keep creation mode active. The saved form remains in develop->forms for
    // session rendering, while the visible form becomes the next unfinished
    // shape so mouse events still target the creation preview.
    dt_masks_form_t *next_form = dt_masks_create(mask_gui->creation_type);
    if(IS_NULL_PTR(next_form))
    {
      dt_masks_form_exit_creation(module, mask_gui);
      return;
    }
 
    g_list_free_full(mask_gui->points, dt_masks_form_gui_points_free);
    mask_gui->points = NULL;
    dt_masks_dynbuf_free(mask_gui->guipoints);
    mask_gui->guipoints = NULL;
    dt_masks_dynbuf_free(mask_gui->guipoints_payload);
    mask_gui->guipoints_payload = NULL;
    mask_gui->guipoints_count = 0;
    mask_gui->pipe_hash = DT_PIXELPIPE_CACHE_HASH_INVALID;
    mask_gui->formid = 0;
    mask_gui->creation_closing_form = FALSE;
    dt_masks_soft_reset_form_gui(mask_gui);
    dt_masks_set_visible_form(develop, next_form);
    if(!IS_NULL_PTR(module)) dt_masks_iop_update(module);
  }
}
 
int dt_masks_form_duplicate(dt_develop_t *develop, int form_id)
{
  // we create a new empty form
  dt_masks_form_t *base_form = dt_masks_get_from_id(develop, form_id);
  if(IS_NULL_PTR(base_form)) return -1;
  dt_masks_form_t *dest_form = dt_masks_create(base_form->type);
  _check_id(dest_form);
 
  // we copy the base values
  dest_form->source[0] = base_form->source[0];
  dest_form->source[1] = base_form->source[1];
  dest_form->version = base_form->version;
  snprintf(dest_form->name, sizeof(dest_form->name), _("copy of %s"), base_form->name);
 
  dt_masks_append_form(develop, dest_form);
 
  // we copy all the points
  if(base_form->functions)
    base_form->functions->duplicate_points(develop, base_form, dest_form);
 
  // and we return its id
  return dest_form->formid;
}
 
int dt_masks_get_points_border(dt_develop_t *develop, dt_masks_form_t *mask_form,
                               float **point_buffer, int *point_count,
                               float **border_buffer, int *border_count,
                               int source, dt_iop_module_t *module)
{
  if(mask_form->functions && mask_form->functions->get_points_border)
    return mask_form->functions->get_points_border(develop, mask_form, point_buffer, point_count,
                                                   border_buffer, border_count, source, module);
  return 1;
}
 
int dt_masks_get_area(dt_iop_module_t *module, dt_dev_pixelpipe_t *pipe,
                      dt_dev_pixelpipe_iop_t *piece, dt_masks_form_t *mask_form,
                      int *area_width, int *area_height, int *area_pos_x, int *area_pos_y)
{
  if(mask_form->functions && mask_form->functions->get_area)
    return mask_form->functions->get_area(module, pipe, piece, mask_form, area_width, area_height,
                                          area_pos_x, area_pos_y);
  return 1;
}
 
int dt_masks_get_source_area(dt_iop_module_t *module, dt_dev_pixelpipe_t *pipe,
                             dt_dev_pixelpipe_iop_t *piece, dt_masks_form_t *mask_form,
                             int *area_width, int *area_height,
                             int *area_pos_x, int *area_pos_y)
{
  *area_width = *area_height = *area_pos_x = *area_pos_y = 0;
 
  // must be a clone form
  if(mask_form->type & DT_MASKS_CLONE)
  {
    if(mask_form->functions && mask_form->functions->get_source_area)
      return mask_form->functions->get_source_area(module, pipe, piece, mask_form, area_width, area_height,
                                                   area_pos_x, area_pos_y);
  }
  return 1;
}
 
int dt_masks_version(void)
{
  return DEVELOP_MASKS_VERSION;
}
 
static int dt_masks_legacy_params_v1_to_v2(dt_develop_t *develop, void *params)
{
  /*
   * difference: before v2 images were originally rotated on load, and then
   * maybe in flip iop
   * after v2: images are only rotated in flip iop.
   */
 
  dt_masks_form_t *mask_form = (dt_masks_form_t *)params;
 
  const dt_image_orientation_t orientation = dt_image_orientation(&develop->image_storage);
 
  if(orientation == ORIENTATION_NONE)
  {
    // image is not rotated, we're fine!
    mask_form->version = 2;
    return 0;
  }
  else
  {
    if(IS_NULL_PTR(develop->iop)) return 1;
 
    const char *opname = "flip";
    dt_iop_module_t *module = NULL;
 
    for(GList *module_node = develop->iop; module_node; module_node = g_list_next(module_node))
    {
      dt_iop_module_t *iop_module = (dt_iop_module_t *)module_node->data;
      if(!strcmp(iop_module->op, opname))
      {
        module = iop_module;
        break;
      }
    }
 
    if(IS_NULL_PTR(module)) return 1;
 
    dt_dev_pixelpipe_iop_t piece = { 0 };
 
    module->init_pipe(module, NULL, &piece);
    module->commit_params(module, module->default_params, NULL, &piece);
 
    piece.buf_in.width = 1;
    piece.buf_in.height = 1;
 
    GList *point_node = mask_form->points;
 
    if(IS_NULL_PTR(point_node)) return 1;
 
    if(mask_form->type & DT_MASKS_CIRCLE)
    {
      dt_masks_node_circle_t *circle = (dt_masks_node_circle_t *)point_node->data;
      if(IS_NULL_PTR(circle)) return 1;
      module->distort_backtransform(module, NULL, &piece, circle->center, 1);
    }
    else if(mask_form->type & DT_MASKS_POLYGON)
    {
      for(; point_node; point_node = g_list_next(point_node))
      {
        dt_masks_node_polygon_t *polygon_node = (dt_masks_node_polygon_t *)point_node->data;
        if(IS_NULL_PTR(polygon_node)) return 1;
        module->distort_backtransform(module, NULL, &piece, polygon_node->node, 1);
        module->distort_backtransform(module, NULL, &piece, polygon_node->ctrl1, 1);
        module->distort_backtransform(module, NULL, &piece, polygon_node->ctrl2, 1);
      }
    }
    else if(mask_form->type & DT_MASKS_GRADIENT)
    { // TODO: new ones have wrong rotation.
      dt_masks_anchor_gradient_t *gradient = (dt_masks_anchor_gradient_t *)point_node->data;
      if(IS_NULL_PTR(gradient)) return 1;
      module->distort_backtransform(module, NULL, &piece, gradient->center, 1);
 
      if(orientation == ORIENTATION_ROTATE_180_DEG)
        gradient->rotation -= 180.0f;
      else if(orientation == ORIENTATION_ROTATE_CCW_90_DEG)
        gradient->rotation -= 90.0f;
      else if(orientation == ORIENTATION_ROTATE_CW_90_DEG)
        gradient->rotation -= -90.0f;
    }
    else if(mask_form->type & DT_MASKS_ELLIPSE)
    {
      dt_masks_node_ellipse_t *ellipse = (dt_masks_node_ellipse_t *)point_node->data;
      module->distort_backtransform(module, NULL, &piece, ellipse->center, 1);
 
      if(orientation & ORIENTATION_SWAP_XY)
      {
        const float y = ellipse->radius[0];
        ellipse->radius[0] = ellipse->radius[1];
        ellipse->radius[1] = y;
      }
    }
    else if(mask_form->type & DT_MASKS_BRUSH)
    {
      for(; point_node; point_node = g_list_next(point_node))
      {
        dt_masks_node_brush_t *brush_node = (dt_masks_node_brush_t *)point_node->data;
        if(IS_NULL_PTR(brush_node)) return 1;
        module->distort_backtransform(module, NULL, &piece, brush_node->node, 1);
        module->distort_backtransform(module, NULL, &piece, brush_node->ctrl1, 1);
        module->distort_backtransform(module, NULL, &piece, brush_node->ctrl2, 1);
      }
    }
 
    if(mask_form->type & DT_MASKS_CLONE)
    {
      // NOTE: can be: DT_MASKS_CIRCLE, DT_MASKS_ELLIPSE, DT_MASKS_POLYGON
      module->distort_backtransform(module, NULL, &piece, mask_form->source, 1);
    }
 
    mask_form->version = 2;
 
    return 0;
  }
}
 
static void dt_masks_legacy_params_v2_to_v3_transform(const dt_image_t *image, float *coords)
{
  const float image_width = (float)image->width;
  const float image_height = (float)image->height;
 
  const float crop_x = (float)image->crop_x;
  const float crop_y = (float)image->crop_y;
 
  const float crop_width = (float)(image->width - image->crop_x - image->crop_width);
  const float crop_height = (float)(image->height - image->crop_y - image->crop_height);
 
  /*
   * masks coordinates are normalized, so we need to:
   * 1. de-normalize them by image original cropped dimensions
   * 2. un-crop them by adding top-left crop coordinates
   * 3. normalize them by the image fully uncropped dimensions
   */
  coords[0] = ((coords[0] * crop_width) + crop_x) / image_width;
  coords[1] = ((coords[1] * crop_height) + crop_y) / image_height;
}
 
static void dt_masks_legacy_params_v2_to_v3_transform_only_rescale(const dt_image_t *image, float *coords,
                                                                   size_t coords_count)
{
  const float image_width = (float)image->width;
  const float image_height = (float)image->height;
 
  const float crop_width = (float)(image->width - image->crop_x - image->crop_width);
  const float crop_height = (float)(image->height - image->crop_y - image->crop_height);
 
  /*
   * masks coordinates are normalized, so we need to:
   * 1. de-normalize them by minimal of image original cropped dimensions
   * 2. normalize them by the minimal of image fully uncropped dimensions
   */
  const float crop_min = MIN(crop_width, crop_height);
  const float image_min = MIN(image_width, image_height);
  for(size_t coord_index = 0; coord_index < coords_count; coord_index++)
    coords[coord_index] = ((coords[coord_index] * crop_min)) / image_min;
}
 
static int dt_masks_legacy_params_v2_to_v3(dt_develop_t *develop, void *params)
{
  /*
   * difference: before v3 images were originally cropped on load
   * after v3: images are cropped in rawprepare iop.
   */
 
  dt_masks_form_t *mask_form = (dt_masks_form_t *)params;
 
  const dt_image_t *image = &(develop->image_storage);
 
  if(image->crop_x == 0 && image->crop_y == 0 && image->crop_width == 0 && image->crop_height == 0)
  {
    // image has no "raw cropping", we're fine!
    mask_form->version = 3;
    return 0;
  }
  else
  {
    GList *point_node = mask_form->points;
 
    if(IS_NULL_PTR(point_node)) return 1;
 
    if(mask_form->type & DT_MASKS_CIRCLE)
    {
      dt_masks_node_circle_t *circle = (dt_masks_node_circle_t *)point_node->data;
      if(IS_NULL_PTR(circle)) return 1;
      dt_masks_legacy_params_v2_to_v3_transform(image, circle->center);
      dt_masks_legacy_params_v2_to_v3_transform_only_rescale(image, &circle->radius, 1);
      dt_masks_legacy_params_v2_to_v3_transform_only_rescale(image, &circle->border, 1);
    }
    else if(mask_form->type & DT_MASKS_POLYGON)
    {
      for(; point_node; point_node = g_list_next(point_node))
      {
        dt_masks_node_polygon_t *polygon_node = (dt_masks_node_polygon_t *)point_node->data;
        if(IS_NULL_PTR(polygon_node)) return 1;
        dt_masks_legacy_params_v2_to_v3_transform(image, polygon_node->node);
        dt_masks_legacy_params_v2_to_v3_transform(image, polygon_node->ctrl1);
        dt_masks_legacy_params_v2_to_v3_transform(image, polygon_node->ctrl2);
        dt_masks_legacy_params_v2_to_v3_transform_only_rescale(image, polygon_node->border, 2);
      }
    }
    else if(mask_form->type & DT_MASKS_GRADIENT)
    {
      dt_masks_anchor_gradient_t *gradient = (dt_masks_anchor_gradient_t *)point_node->data;
      dt_masks_legacy_params_v2_to_v3_transform(image, gradient->center);
    }
    else if(mask_form->type & DT_MASKS_ELLIPSE)
    {
      dt_masks_node_ellipse_t *ellipse = (dt_masks_node_ellipse_t *)point_node->data;
      dt_masks_legacy_params_v2_to_v3_transform(image, ellipse->center);
      dt_masks_legacy_params_v2_to_v3_transform_only_rescale(image, ellipse->radius, 2);
      dt_masks_legacy_params_v2_to_v3_transform_only_rescale(image, &ellipse->border, 1);
    }
    else if(mask_form->type & DT_MASKS_BRUSH)
    {
      for(; point_node;  point_node = g_list_next(point_node))
      {
        dt_masks_node_brush_t *brush_node = (dt_masks_node_brush_t *)point_node->data;
        if(IS_NULL_PTR(brush_node)) return 1;
        dt_masks_legacy_params_v2_to_v3_transform(image, brush_node->node);
        dt_masks_legacy_params_v2_to_v3_transform(image, brush_node->ctrl1);
        dt_masks_legacy_params_v2_to_v3_transform(image, brush_node->ctrl2);
        dt_masks_legacy_params_v2_to_v3_transform_only_rescale(image, brush_node->border, 2);
      }
    }
 
    if(mask_form->type & DT_MASKS_CLONE)
    {
      // NOTE: can be: DT_MASKS_CIRCLE, DT_MASKS_ELLIPSE, DT_MASKS_POLYGON
      dt_masks_legacy_params_v2_to_v3_transform(image, mask_form->source);
    }
 
    mask_form->version = 3;
 
    return 0;
  }
}
 
static int dt_masks_legacy_params_v3_to_v4(dt_develop_t *develop, void *params)
{
  /*
   * difference affecting ellipse
   * up to v3: only equidistant feathering
   * after v4: choice between equidistant and proportional feathering
   * type of feathering is defined in new flags parameter
   */
 
  dt_masks_form_t *mask_form = (dt_masks_form_t *)params;
 
  GList *point_node = mask_form->points;
 
  if(IS_NULL_PTR(point_node)) return 1;
 
  if(mask_form->type & DT_MASKS_ELLIPSE)
  {
    dt_masks_node_ellipse_t *ellipse = (dt_masks_node_ellipse_t *)point_node->data;
    ellipse->flags = DT_MASKS_ELLIPSE_EQUIDISTANT;
  }
 
  mask_form->version = 4;
 
  return 0;
}
 
 
static int dt_masks_legacy_params_v4_to_v5(dt_develop_t *develop, void *params)
{
  /*
   * difference affecting gradient
   * up to v4: only linear gradient (relative to input image)
   * after v5: curved gradients
   */
 
  dt_masks_form_t *mask_form = (dt_masks_form_t *)params;
 
  GList *point_node = mask_form->points;
 
  if(IS_NULL_PTR(point_node)) return 1;
 
  if(mask_form->type & DT_MASKS_GRADIENT)
  {
    dt_masks_anchor_gradient_t *gradient = (dt_masks_anchor_gradient_t *)point_node->data;
    gradient->curvature = 0.0f;
  }
 
  mask_form->version = 5;
 
  return 0;
}
 
static int dt_masks_legacy_params_v5_to_v6(dt_develop_t *develop, void *params)
{
  /*
   * difference affecting gradient
   * up to v5: linear transition
   * after v5: linear or sigmoidal transition
   */
 
  dt_masks_form_t *mask_form = (dt_masks_form_t *)params;
 
  GList *point_node = mask_form->points;
 
  if(IS_NULL_PTR(point_node)) return 1;
 
  if(mask_form->type & DT_MASKS_GRADIENT)
  {
    dt_masks_anchor_gradient_t *gradient = (dt_masks_anchor_gradient_t *)point_node->data;
    gradient->state = DT_MASKS_GRADIENT_STATE_LINEAR;
  }
 
  mask_form->version = 6;
 
  return 0;
}
 
 
int dt_masks_legacy_params(dt_develop_t *develop, void *params, const int old_version, const int new_version)
{
  int result = 1;
#if 0 // we should not need this any longer
  if(old_version == 1 && new_version == 2)
  {
    result = dt_masks_legacy_params_v1_to_v2(develop, params);
  }
#endif
 
  if(old_version == 1 && new_version == 6)
  {
    result = dt_masks_legacy_params_v1_to_v2(develop, params);
    if(!result) result = dt_masks_legacy_params_v2_to_v3(develop, params);
    if(!result) result = dt_masks_legacy_params_v3_to_v4(develop, params);
    if(!result) result = dt_masks_legacy_params_v4_to_v5(develop, params);
    if(!result) result = dt_masks_legacy_params_v5_to_v6(develop, params);
  }
  else if(old_version == 2 && new_version == 6)
  {
    result = dt_masks_legacy_params_v2_to_v3(develop, params);
    if(!result) result = dt_masks_legacy_params_v3_to_v4(develop, params);
    if(!result) result = dt_masks_legacy_params_v4_to_v5(develop, params);
    if(!result) result = dt_masks_legacy_params_v5_to_v6(develop, params);
  }
  else if(old_version == 3 && new_version == 6)
  {
    result = dt_masks_legacy_params_v3_to_v4(develop, params);
    if(!result) result = dt_masks_legacy_params_v4_to_v5(develop, params);
    if(!result) result = dt_masks_legacy_params_v5_to_v6(develop, params);
  }
  else if(old_version == 4 && new_version == 6)
  {
    result = dt_masks_legacy_params_v4_to_v5(develop, params);
    if(!result) result = dt_masks_legacy_params_v5_to_v6(develop, params);
  }
  else if(old_version == 5 && new_version == 6)
  {
    result = dt_masks_legacy_params_v5_to_v6(develop, params);
  }
 
  return result;
}
 
static int form_id_seed = 0;
 
dt_masks_form_t *dt_masks_create(dt_masks_type_t type)
{
  dt_masks_form_t *mask_form = (dt_masks_form_t *)calloc(1, sizeof(dt_masks_form_t));
  if(IS_NULL_PTR(mask_form)) return NULL;
 
  mask_form->type = type;
  mask_form->version = dt_masks_version();
  mask_form->formid = time(NULL) + form_id_seed++;
  mask_form->uses_bezier_points_layout = (type & (DT_MASKS_BRUSH | DT_MASKS_POLYGON)) ? TRUE : FALSE;
 
  if (type & DT_MASKS_CIRCLE)
    mask_form->functions = &dt_masks_functions_circle;
  else if (type & DT_MASKS_ELLIPSE)
    mask_form->functions = &dt_masks_functions_ellipse;
  else if (type & DT_MASKS_BRUSH)
    mask_form->functions = &dt_masks_functions_brush;
  else if (type & DT_MASKS_POLYGON)
    mask_form->functions = &dt_masks_functions_polygon;
  else if (type & DT_MASKS_GRADIENT)
    mask_form->functions = &dt_masks_functions_gradient;
  else if (type & DT_MASKS_GROUP)
    mask_form->functions = &dt_masks_functions_group;
 
  if (mask_form->functions && mask_form->functions->sanitize_config)
    mask_form->functions->sanitize_config(type);
 
  return mask_form;
}
 
dt_masks_form_t *dt_masks_create_ext(dt_masks_type_t type)
{
  dt_pthread_rwlock_wrlock(&darktable.develop->masks_mutex);
  dt_masks_form_t *mask_form = dt_masks_create(type);
 
  // all forms created here are registered in darktable.develop->allforms for later cleanup
  if(mask_form)
    darktable.develop->allforms = g_list_append(darktable.develop->allforms, mask_form);
 
  dt_pthread_rwlock_unlock(&darktable.develop->masks_mutex);
 
  return mask_form;
}
 
void dt_masks_replace_current_forms(dt_develop_t *develop, GList *forms)
{
  dt_pthread_rwlock_wrlock(&develop->masks_mutex);
  GList *forms_tmp = dt_masks_dup_forms_deep(forms, NULL);
 
  while(develop->forms)
  {
    darktable.develop->allforms = g_list_append(darktable.develop->allforms, develop->forms->data);
    develop->forms = g_list_delete_link(develop->forms, develop->forms);
  }
 
  develop->forms = forms_tmp;
  dt_pthread_rwlock_unlock(&develop->masks_mutex);
 
  for(GList *form_node = develop->forms; form_node; form_node = g_list_next(form_node))
  {
    dt_masks_form_t *mask_form = (dt_masks_form_t *)form_node->data;
    dt_masks_form_update_gravity_center(mask_form);
  }
}
 
dt_masks_form_t *dt_masks_get_from_id_ext(GList *form_list, int form_id)
{
  for(; form_list; form_list = g_list_next(form_list))
  {
    dt_masks_form_t *mask_form = (dt_masks_form_t *)form_list->data;
    if(mask_form->formid == form_id) return mask_form;
  }
  return NULL;
}
 
dt_masks_form_t *dt_masks_get_from_id(dt_develop_t *develop, int form_id)
{
  dt_pthread_rwlock_rdlock(&develop->masks_mutex);
  dt_masks_form_t *result = dt_masks_get_from_id_ext(develop->forms, form_id);
  dt_pthread_rwlock_unlock(&develop->masks_mutex);
  return result;
}
 
dt_iop_module_t *dt_masks_get_mask_manager(dt_develop_t *develop)
{
  for(GList *module_node = g_list_first(develop->iop); module_node; module_node = g_list_next(module_node))
  {
    dt_iop_module_t *module = (dt_iop_module_t *)(module_node->data);
    if(strcmp(module->op, "mask_manager") == 0)
      return module;
  }
  return NULL;
}
 
GList *dt_masks_snapshot_current_forms(dt_develop_t *develop, gboolean reset_changed)
{
  dt_pthread_rwlock_rdlock(&develop->masks_mutex);
  GList *forms_snapshot = dt_masks_dup_forms_deep(develop->forms, NULL);
  dt_pthread_rwlock_unlock(&develop->masks_mutex);
  if(reset_changed) develop->forms_changed = FALSE;
  return forms_snapshot;
}
 
static void _masks_fill_used_forms(GList *forms_list, const int form_id, int *used_form_ids,
                                   const int used_count)
{
  for(int used_index = 0; used_index < used_count; used_index++)
  {
    if(used_form_ids[used_index] == 0)
    {
      used_form_ids[used_index] = form_id;
      break;
    }
    if(used_form_ids[used_index] == form_id) break;
  }
 
  dt_masks_form_t *mask_form = dt_masks_get_from_id_ext(forms_list, form_id);
  if(!IS_NULL_PTR(mask_form) && (mask_form->type & DT_MASKS_GROUP))
  {
    for(GList *group_node = mask_form->points; group_node; group_node = g_list_next(group_node))
    {
      dt_masks_form_group_t *group_entry = (dt_masks_form_group_t *)group_node->data;
      _masks_fill_used_forms(forms_list, group_entry->formid, used_form_ids, used_count);
    }
  }
}
 
int dt_masks_copy_used_forms_for_module(dt_develop_t *develop_dest, dt_develop_t *develop_src,
                                        const dt_iop_module_t *source_module)
{
  if(!(source_module->flags() & IOP_FLAGS_SUPPORTS_BLENDING)) return 0;
  if(source_module->blend_params->mask_id <= 0) return 0;
 
  const guint form_count = g_list_length(develop_src->forms);
  if(form_count == 0) return 0;
 
  int *used_form_ids = calloc(form_count, sizeof(int));
  if(IS_NULL_PTR(used_form_ids)) return 1;
 
  _masks_fill_used_forms(develop_src->forms, source_module->blend_params->mask_id,
                         used_form_ids, form_count);
 
  for(int form_index = 0; form_index < (int)form_count && used_form_ids[form_index] > 0; form_index++)
  {
    dt_masks_form_t *mask_form = dt_masks_get_from_id(develop_src, used_form_ids[form_index]);
    if(!IS_NULL_PTR(mask_form))
    {
      dt_masks_form_t *existing_form = dt_masks_get_from_id_ext(develop_dest->forms,
                                                                used_form_ids[form_index]);
      if(existing_form)
      {
        develop_dest->forms = g_list_remove(develop_dest->forms, existing_form);
        develop_dest->allforms = g_list_append(develop_dest->allforms, existing_form);
      }
 
      dt_masks_form_t *new_form = dt_masks_dup_masks_form(mask_form);
      if(IS_NULL_PTR(new_form))
      {
        dt_free(used_form_ids);
        return 1;
      }
      develop_dest->forms = g_list_append(develop_dest->forms, new_form);
    }
    else
    {
      fprintf(stderr, "[dt_masks_copy_used_forms_for_module] form %i not found in source image\n",
              used_form_ids[form_index]);
    }
  }
 
  dt_free(used_form_ids);
  return 0;
}
 
void dt_masks_read_masks_history(dt_develop_t *develop, const int32_t image_id)
{
  dt_dev_history_item_t *history_item = NULL;
  dt_dev_history_item_t *last_history_item = NULL;
  int previous_num = -1;
 
  sqlite3_stmt *statement = NULL;
  // clang-format off
  DT_DEBUG_SQLITE3_PREPARE_V2(
      dt_database_get(darktable.db),
      "SELECT imgid, formid, form, name, version, points, points_count, source, num "
      "FROM main.masks_history WHERE imgid = ?1 ORDER BY num",
      -1, &statement, NULL);
  // clang-format on
  DT_DEBUG_SQLITE3_BIND_INT(statement, 1, image_id);
 
  while(sqlite3_step(statement) == SQLITE_ROW)
  {
    // db record:
    // 0-img, 1-formid, 2-form_type, 3-name, 4-version, 5-points, 6-points_count, 7-source, 8-num
 
    // we get the values
 
    const int form_id = sqlite3_column_int(statement, 1);
    const int history_num = sqlite3_column_int(statement, 8);
    const dt_masks_type_t mask_type = sqlite3_column_int(statement, 2);
    dt_masks_form_t *mask_form = dt_masks_create(mask_type);
    mask_form->formid = form_id;
    const char *form_name = (const char *)sqlite3_column_text(statement, 3);
    g_strlcpy(mask_form->name, form_name, sizeof(mask_form->name));
    mask_form->version = sqlite3_column_int(statement, 4);
    mask_form->points = NULL;
    const int point_count = sqlite3_column_int(statement, 6);
    memcpy(mask_form->source, sqlite3_column_blob(statement, 7), sizeof(float) * 2);
 
    // and now we "read" the blob
    if(mask_form->functions)
    {
      const char *const point_buffer = (char *)sqlite3_column_blob(statement, 5);
      const size_t point_struct_size = mask_form->functions->point_struct_size;
      for(int point_index = 0; point_index < point_count; point_index++)
      {
        char *point_data = (char *)malloc(point_struct_size);
        memcpy(point_data, point_buffer + point_index * point_struct_size, point_struct_size);
        mask_form->points = g_list_append(mask_form->points, point_data);
      }
    }
 
    if(mask_form->version != dt_masks_version())
    {
      if(dt_masks_legacy_params(develop, mask_form, mask_form->version, dt_masks_version()))
      {
        const char *fname = develop->image_storage.filename + strlen(develop->image_storage.filename);
        while(fname > develop->image_storage.filename && *fname != '/') fname--;
        if(fname > develop->image_storage.filename) fname++;
 
        fprintf(stderr,
                "[_dev_read_masks_history] %s (imgid `%i'): mask version mismatch: history is %d, dt %d.\n",
                fname, image_id, mask_form->version, dt_masks_version());
        dt_control_log(_("%s: mask version mismatch: %d != %d"),
                       fname, dt_masks_version(), mask_form->version);
 
        continue;
      }
    }
 
    dt_masks_form_update_gravity_center(mask_form);
 
    // if this is a new history entry let's find it
    if(previous_num != history_num)
    {
      history_item = NULL;
      for(GList *history_node = g_list_first(develop->history); history_node; history_node = g_list_next(history_node))
      {
        dt_dev_history_item_t *history_entry = (dt_dev_history_item_t *)(history_node->data);
        if(history_entry->num == history_num)
        {
          history_item = history_entry;
          break;
        }
      }
      previous_num = history_num;
    }
    // add the form to the history entry
    // FIXME: there is no reason to hack history_item to add a forms snapshot that doesn't
    // belong to it because dt_dev_write_history_item() doesn't save history_item->forms to the DB.
    // So this forms snapshot should be attached to its own object, and that object should be
    // linked by ID to the history_item object. That would allow to share one forms snapshot
    // between several history items without duplication.
    if(history_item)
    {
      history_item->forms = g_list_append(history_item->forms, mask_form);
    }
    else
      fprintf(stderr,
              "[_dev_read_masks_history] can't find history entry %i while adding mask %s(%i)\n",
              history_num, mask_form->name, form_id);
 
    if(history_num < dt_dev_get_history_end_ext(develop)) last_history_item = history_item;
  }
  sqlite3_finalize(statement);
 
  // and we update the current forms snapshot
  dt_masks_replace_current_forms(develop, (last_history_item) ? last_history_item->forms : NULL);
}
 
void dt_masks_write_masks_history_item(const int32_t image_id, const int history_num,
                                       dt_masks_form_t *mask_form)
{
  sqlite3_stmt *statement = NULL;
 
  dt_print(DT_DEBUG_HISTORY, "[dt_masks_write_masks_history_item] writing mask %s of type %i for image %i\n",
           mask_form->name, mask_form->type, image_id);
 
  // write the form into the database
  // clang-format off
  DT_DEBUG_SQLITE3_PREPARE_V2(dt_database_get(darktable.db),
                              "INSERT INTO main.masks_history (imgid, num, formid, form, name, "
                              "version, points, points_count,source) VALUES "
                              "(?1, ?9, ?2, ?3, ?4, ?5, ?6, ?7, ?8)",
                              -1, &statement, NULL);
  // clang-format on
  DT_DEBUG_SQLITE3_BIND_INT(statement, 1, image_id);
  DT_DEBUG_SQLITE3_BIND_INT(statement, 9, history_num);
  DT_DEBUG_SQLITE3_BIND_INT(statement, 2, mask_form->formid);
  DT_DEBUG_SQLITE3_BIND_INT(statement, 3, mask_form->type);
  DT_DEBUG_SQLITE3_BIND_TEXT(statement, 4, mask_form->name, -1, SQLITE_TRANSIENT);
  DT_DEBUG_SQLITE3_BIND_BLOB(statement, 8, mask_form->source, 2 * sizeof(float), SQLITE_TRANSIENT);
  DT_DEBUG_SQLITE3_BIND_INT(statement, 5, mask_form->version);
  if(mask_form->functions)
  {
    const size_t point_struct_size = mask_form->functions->point_struct_size;
    const guint point_count = g_list_length(mask_form->points);
    char *const restrict point_buffer = (char *)malloc(point_count * point_struct_size);
    int buffer_offset = 0;
    for(GList *point_node = mask_form->points; point_node; point_node = g_list_next(point_node))
    {
      memcpy(point_buffer + buffer_offset, point_node->data, point_struct_size);
      buffer_offset += point_struct_size;
    }
    DT_DEBUG_SQLITE3_BIND_BLOB(statement, 6, point_buffer,
                               point_count * point_struct_size, SQLITE_TRANSIENT);
    DT_DEBUG_SQLITE3_BIND_INT(statement, 7, point_count);
    sqlite3_step(statement);
    sqlite3_finalize(statement);
    dt_free(point_buffer);
  }
}
 
void dt_masks_free_form(dt_masks_form_t *mask_form)
{
  if(IS_NULL_PTR(mask_form)) return;
  g_list_free_full(mask_form->points, dt_free_gpointer);
  mask_form->points = NULL;
  dt_free(mask_form);
}
 
int dt_masks_events_mouse_leave(struct dt_iop_module_t *module)
{
  return 0;
}
 
int dt_masks_events_mouse_enter(struct dt_iop_module_t *module)
{
  return 0;
}
 
gboolean dt_masks_is_anything_selected(const dt_masks_form_gui_t *mask_gui)
{
  return mask_gui->form_selected
          || mask_gui->source_selected
          || mask_gui->seg_selected
          || mask_gui->node_selected
          || mask_gui->handle_selected
          || mask_gui->handle_border_selected;
}
 
gboolean dt_masks_is_anything_hovered(const dt_masks_form_gui_t *mask_gui)
{
  return mask_gui->node_hovered >= 0
          || mask_gui->handle_hovered >= 0
          || mask_gui->handle_border_hovered >= 0
          || mask_gui->seg_hovered >= 0;
}
 
static void _set_cursor_shape(dt_masks_form_gui_t *mask_gui)
{
  if(IS_NULL_PTR(mask_gui)) return;
 
  // circular arrows
  if(mask_gui->pivot_selected)
    dt_control_queue_cursor(GDK_EXCHANGE);
  // pointing hand
  else if(mask_gui->creation_closing_form)
    dt_control_queue_cursor(GDK_HAND2);
 
  /*else if(gui->handle_dragging >= 0)
    dt_control_set_cursor(GDK_HAND1);*/
 
  // crosshair
  else if(!mask_gui->creation
          && (dt_masks_is_anything_selected(mask_gui)
              || dt_masks_is_anything_hovered(mask_gui)))
    dt_control_queue_cursor(GDK_FLEUR);
}
 
static void _apply_gui_button_pressed_state(dt_masks_form_gui_t *mask_gui, const int button,
                                            const uint32_t state,
                                            const gboolean shape_was_selected)
{
  if(IS_NULL_PTR(mask_gui) || mask_gui->creation || button != 1) return;
  // Drag is only allowed when this click happens on a shape that was already selected.
  // We still rebuild the fine-grained selection from the current hover target first, so the
  // pressed node/handle/segment becomes the active drag target when dragging is allowed.
  const gboolean prev_node_selected = mask_gui->node_selected;
  const int prev_node_selected_idx = mask_gui->node_selected_idx;
  const gboolean prev_form_selected = mask_gui->form_selected;
  const gboolean prev_border_selected = mask_gui->border_selected;
  const gboolean prev_source_selected = mask_gui->source_selected;
 
  mask_gui->node_selected = FALSE;
  mask_gui->handle_selected = FALSE;
  mask_gui->handle_border_selected = FALSE;
  mask_gui->seg_selected = FALSE;
  mask_gui->node_selected_idx = -1;
  mask_gui->form_selected = FALSE;
  mask_gui->border_selected = FALSE;
  mask_gui->source_selected = FALSE;
 
  if(mask_gui->node_hovered >= 0)
  {
    mask_gui->node_selected = TRUE;
    mask_gui->node_selected_idx = mask_gui->node_hovered;
  }
  else if(mask_gui->handle_hovered >= 0)
  {
    if(prev_node_selected)
    {
      mask_gui->node_selected = TRUE;
      mask_gui->node_selected_idx = prev_node_selected_idx;
    }
    mask_gui->handle_selected = TRUE;
  }
  else if(mask_gui->handle_border_hovered >= 0)
  {
    if(prev_node_selected)
    {
      mask_gui->node_selected = TRUE;
      mask_gui->node_selected_idx = prev_node_selected_idx;
    }
    mask_gui->handle_border_selected = TRUE;
  }
  else if(mask_gui->seg_hovered >= 0)
  {
    mask_gui->seg_selected = TRUE;
  }
  else
  {
    mask_gui->form_selected = prev_form_selected;
    mask_gui->border_selected = prev_border_selected;
    mask_gui->source_selected = prev_source_selected;
  }
 
  if(mask_gui->form_rotating || mask_gui->border_toggling || mask_gui->gradient_toggling) return;
  if(dt_modifier_is(state, GDK_CONTROL_MASK)) return;
  if(!shape_was_selected) return;
 
  dt_masks_gui_set_dragging(mask_gui);
}
 
static void _dt_masks_events_set_current_pos(const double x, const double y, dt_masks_form_gui_t *mask_gui)
{
  if(IS_NULL_PTR(mask_gui)) return;
 
  float point[2] = { (float)x, (float)y };
  dt_dev_coordinates_widget_to_image_norm(darktable.develop, point, 1);
  mask_gui->rel_pos[0] = point[0];
  mask_gui->rel_pos[1] = point[1];
 
  dt_dev_coordinates_image_norm_to_image_abs(darktable.develop, point, 1);
  mask_gui->pos[0] = point[0];
  mask_gui->pos[1] = point[1];
 
  mask_gui->raw_pos[0] = point[0];
  mask_gui->raw_pos[1] = point[1];
  dt_dev_coordinates_image_abs_to_raw_abs(darktable.develop, mask_gui->raw_pos, 1);
}
 
int dt_masks_events_mouse_moved(struct dt_iop_module_t *module, double x, double y, double pressure, int which)
{
  // This assume that if this event is generated, the mouse is over the center window.
  // record mouse position even if there are no masks visible
  dt_masks_form_gui_t *mask_gui = darktable.develop->form_gui;
  dt_masks_form_t *mask_form = dt_masks_get_visible_form(darktable.develop);
  if(IS_NULL_PTR(mask_gui)) return 0;
  _dt_masks_events_set_current_pos(x, y, mask_gui);
 
  // do not process if no forms visible
  if(IS_NULL_PTR(mask_form)) return 0;
 
  // add an option to allow skip mouse events while editing masks
  if(darktable.develop->darkroom_skip_mouse_events) return 0;
 
  int result = 0;
  if((mask_form->type & DT_MASKS_GROUP) && _dt_masks_events_group_blocks_motion(mask_gui))
  {
    result = 1;
  }
  else
  {
    dt_masks_form_group_t *group_entry = NULL;
    int parent_id = 0;
    int form_index = 0;
    dt_masks_form_t *dispatch_form
        = _dt_masks_events_get_dispatch_form(mask_form, mask_gui, &group_entry, &parent_id, &form_index);
 
    if(_dt_masks_events_should_update_hover_on_move(mask_gui))
      result = _dt_masks_events_update_hover(dispatch_form, mask_gui, form_index);
 
    if(!result && dispatch_form && dispatch_form->functions && dispatch_form->functions->mouse_moved)
      result = dispatch_form->functions->mouse_moved(module, x, y, pressure, which,
                                                     dispatch_form, parent_id, mask_gui, form_index);
  }
 
  if(!IS_NULL_PTR(mask_gui))
  {
    _set_hinter_message(mask_gui, mask_form);
    _set_cursor_shape(mask_gui);
  }
  return result;
}
 
int dt_masks_events_button_released(struct dt_iop_module_t *module, double x, double y, int button,
                                    uint32_t state)
{
  // add an option to allow skip mouse events while editing masks
  if(darktable.develop->darkroom_skip_mouse_events) return 0;
 
  dt_masks_form_t *mask_form = dt_masks_get_visible_form(darktable.develop);
  dt_masks_form_gui_t *mask_gui = darktable.develop->form_gui;
  if(IS_NULL_PTR(mask_gui)) return 0;
  _dt_masks_events_set_current_pos(x, y, mask_gui);
  if(IS_NULL_PTR(mask_form)) return 0;
 
  dt_masks_form_group_t *group_entry = NULL;
  int parent_id = 0;
  int form_index = 0;
  dt_masks_form_t *dispatch_form
      = _dt_masks_events_get_dispatch_form(mask_form, mask_gui, &group_entry, &parent_id, &form_index);
 
  int result = 0;
  if(!IS_NULL_PTR(dispatch_form) && dispatch_form->functions && dispatch_form->functions->button_released)
    result = dispatch_form->functions->button_released(module, x, y, button,
                                                       state, dispatch_form, parent_id, mask_gui, form_index);
 
  if(_dt_masks_events_flush_rebuild_if_needed(module, dispatch_form, mask_gui, form_index, button))
    result = 1;
 
  if(!IS_NULL_PTR(mask_form) && (mask_form->type & DT_MASKS_GROUP) && !IS_NULL_PTR(mask_gui))
  {
    const dt_masks_form_group_t *selected_group_entry
        = dt_masks_form_get_selected_group_live(mask_form, mask_gui);
    if(selected_group_entry)
      dt_dev_masks_selection_change(darktable.develop, module,
                                    selected_group_entry->formid, FALSE);
  }
 
  if(mask_gui && !mask_gui->creation && button == 1)
    dt_masks_gui_reset_dragging(mask_gui);
 
  if(!IS_NULL_PTR(mask_gui))
  {
    _set_hinter_message(mask_gui, mask_form);
    _set_cursor_shape(mask_gui);
  }
 
  return result;
}
 
int dt_masks_events_button_pressed(struct dt_iop_module_t *module, double x, double y, double pressure,
                                   int button, int event_type, uint32_t state)
{
  // add an option to allow skip mouse events while editing masks
  if(darktable.develop->darkroom_skip_mouse_events) return 0;
 
  dt_masks_form_t *mask_form = dt_masks_get_visible_form(darktable.develop);
  dt_masks_form_gui_t *mask_gui = darktable.develop->form_gui;
  if(IS_NULL_PTR(mask_gui)) return 0;
 
  _dt_masks_events_set_current_pos(x, y, mask_gui);
  if(IS_NULL_PTR(mask_form)) return 0;
  const gboolean prev_any_selected = dt_masks_is_anything_selected(mask_gui);
  const int prev_group_selected = mask_gui->group_selected;
 
  /*DT_DEBUG_CONTROL_SIGNAL_RAISE(darktable.signals, DT_SIGNAL_MASK_SELECTION_CHANGED, NULL, NULL);*/
 
  if(mask_form->type & DT_MASKS_GROUP)
    _dt_masks_events_group_update_selection(mask_form, mask_gui);
 
  dt_masks_form_group_t *group_entry = NULL;
  int parent_id = 0;
  int form_index = 0;
  dt_masks_form_t *dispatch_form
      = _dt_masks_events_get_dispatch_form(mask_form, mask_gui, &group_entry, &parent_id, &form_index);
  _dt_masks_events_update_hover(dispatch_form, mask_gui, form_index);
 
  gboolean return_val = FALSE;
  if(!IS_NULL_PTR(dispatch_form) && dispatch_form->functions && dispatch_form->functions->button_pressed)
    return_val = dispatch_form->functions->button_pressed(module, x, y, pressure,
                                                          button, event_type, state,
                                                          dispatch_form, parent_id, mask_gui, form_index);
  // Throw a selection change event.
  // `dispatch_form` can pass NULL in case of deselection.
  dt_masks_select_form(module, dispatch_form);
 
  const gboolean shape_was_selected = (mask_form->type & DT_MASKS_GROUP)
                                          ? (prev_group_selected >= 0 && prev_group_selected == form_index)
                                          : prev_any_selected;
  _apply_gui_button_pressed_state(mask_gui, button, state, shape_was_selected);
 
  if(button == 3 && !return_val)
  {
    // mouse is over a form or one of its handles/nodes
    if(!IS_NULL_PTR(dispatch_form) && (mask_gui->creation
                         || dt_masks_is_anything_hovered(mask_gui)
                         || dt_masks_is_anything_selected(mask_gui)))
    {
      GtkWidget *menu = dt_masks_create_menu(mask_gui, dispatch_form, group_entry,
                                             mask_gui->rel_pos[0], mask_gui->rel_pos[1]);
      if(!IS_NULL_PTR(menu))
      {
        gtk_menu_popup_at_pointer(GTK_MENU(menu), NULL);
        return_val = TRUE;
      }
    }
  }
 
  return return_val;
}
 
int dt_masks_events_key_pressed(struct dt_iop_module_t *module, GdkEventKey *event)
{
  dt_masks_form_t *mask_form = dt_masks_get_visible_form(darktable.develop);
  if(IS_NULL_PTR(mask_form)) return 0;
  dt_masks_form_gui_t *mask_gui = darktable.develop->form_gui;
  if(IS_NULL_PTR(mask_gui)) return 0;
 
  gboolean return_value = FALSE;
  if(mask_form->type & DT_MASKS_GROUP)
  {
    dt_masks_form_group_t *group_entry = NULL;
    int parent_id = 0;
    int form_index = 0;
    dt_masks_form_t *dispatch_form
        = _dt_masks_events_get_dispatch_form(mask_form, mask_gui, &group_entry, &parent_id, &form_index);
    if(dispatch_form && dispatch_form->functions && dispatch_form->functions->key_pressed)
      return_value = dispatch_form->functions->key_pressed(module, event, dispatch_form,
                                                           parent_id, mask_gui, form_index);
 
    if(!return_value && mask_form->functions->key_pressed)
      return_value = mask_form->functions->key_pressed(module, event, mask_form, 0, mask_gui, 0);
  }
  else if(mask_form->functions->key_pressed)
  {
    return_value = mask_form->functions->key_pressed(module, event, mask_form, 0, mask_gui, 0);
  }
  
  if(!return_value)
  {
    guint key = dt_keys_mainpad_alternatives(event->keyval);
    switch(key)
    {
      case GDK_KEY_Escape:
      {
        return_value = dt_masks_form_exit_creation(module, mask_gui);
        break;
      }
      case GDK_KEY_Delete:
      {
        if(mask_gui->group_selected >= 0)
        {
          // Delete shape from current group
          dt_masks_form_group_t *selected_group = dt_masks_form_get_selected_group(mask_form, mask_gui);
          if(IS_NULL_PTR(selected_group)) return 0;
          dt_masks_form_t *selected_form = dt_masks_get_from_id(darktable.develop, selected_group->formid);
          if(selected_form)
            return_value = dt_masks_gui_remove(module, selected_form, mask_gui, selected_group->parentid);
          break;
        }
      }
    }
  }
 
  return return_value;
}
 
int dt_masks_events_mouse_scrolled(struct dt_iop_module_t *module, double x, double y,
                                   int scroll_up, uint32_t key_state, int scrolling_delta)
{
  // add an option to allow skip mouse events while editing masks
  if(darktable.develop->darkroom_skip_mouse_events) return 0;
 
  dt_masks_form_t *mask_form = dt_masks_get_visible_form(darktable.develop);
  dt_masks_form_gui_t *mask_gui = darktable.develop->form_gui;
  if(IS_NULL_PTR(mask_gui)) return 0;
 
  _dt_masks_events_set_current_pos(x, y, mask_gui);
  if(IS_NULL_PTR(mask_form)) return 0;
 
  int result = 0;
  const gboolean scroll_increases = dt_mask_scroll_increases(scroll_up);
 
  // we want delta_y to be an absolute scrolling speed
  int scroll_flow = (scrolling_delta < 0) ? -scrolling_delta : scrolling_delta;
 
  dt_masks_form_group_t *group_entry = NULL;
  int parent_id = 0;
  int form_index = 0;
  dt_masks_form_t *dispatch_form
      = _dt_masks_events_get_dispatch_form(mask_form, mask_gui, &group_entry, &parent_id, &form_index);
 
  if(!mask_gui->creation && !dt_masks_is_anything_selected(mask_gui))
    return 0;
 
  _dt_masks_events_update_hover(dispatch_form, mask_gui, form_index);
 
  if(!mask_gui->creation && !_dt_masks_events_cursor_over_form(dispatch_form, mask_gui, form_index))
    return 0;
 
  if(dispatch_form && dispatch_form->functions && dispatch_form->functions->mouse_scrolled)
    result = dispatch_form->functions->mouse_scrolled(module, x, y,
                                                      scroll_increases ? 1 : 0, scroll_flow,
                                                      key_state, dispatch_form, parent_id, mask_gui, form_index,
                                                      DT_MASKS_INTERACTION_UNDEF);
 
  if(!IS_NULL_PTR(mask_gui))
  {
    const gboolean hinted = _set_hinter_message(mask_gui, mask_form);
    dt_print(DT_DEBUG_INPUT,
             "[masks] scroll: ret=%d hinted=%d form=%p type=%d gui=%p group_selected=%d flow=%d state=0x%x\n",
             result, hinted, (void *)mask_form, mask_form ? mask_form->type : -1, (void *)mask_gui,
             mask_gui->group_selected, scroll_flow, key_state);
    if(hinted)
      result = 1;
  }
  return result;
}
 
gboolean dt_masks_node_is_cusp(const dt_masks_form_gui_points_t *gui_points, const int node_index)
{
  if(IS_NULL_PTR(gui_points) || IS_NULL_PTR(gui_points->points)) return FALSE;
  if(gui_points->points_count <= 0 || node_index < 0 || node_index >= gui_points->points_count) return FALSE;
 
  const float *point_values = &gui_points->points[node_index * 6];
  return (point_values[0 + 2] == point_values[2 + 2]
       && point_values[1 + 2] == point_values[3 + 2]);
}
 
static void _dt_masks_find_best_attachment_point(const float ray_1[2], const float ray_2[2],
                                                 const float *points, const int points_count, const float zoom_scale,
                                                 const int first_pt,
                                                 const gboolean is_closed_shape,
                                                 const float offset_factor,
                                                 float result[2])
{
  // Fallback: no intersection found.
  result[0] = ray_1[0];
  result[1] = ray_1[1];
 
  const int available_points = points_count - first_pt;
  if(available_points < 2) return;
 
  const float ray2_x = ray_2[0];
  const float ray2_y = ray_2[1];
  const float ray_center_x = 0.5f * (ray_1[0] + ray_2[0]);
  const float ray_center_y = 0.5f * (ray_1[1] + ray_2[1]);
  const float dir_x = ray_1[0] - ray_2[0];
  const float dir_y = ray_1[1] - ray_2[1];
  float min_s = FLT_MAX;
  const float offset = DT_PIXEL_APPLY_DPI(12.0f * offset_factor) / zoom_scale;
  const float inv_dir_len = f_inv_sqrtf(dir_x * dir_x + dir_y * dir_y);
  const float ux = dir_x * inv_dir_len;
  const float uy = dir_y * inv_dir_len;
 
 
  const int segment_count = (available_points - 1) + ((is_closed_shape) ? 1 : 0);
  for(int seg = 0; seg < segment_count; seg++)
  {
    // Get the current segment [i, j], with wrap-around if the shape is closed.
    const int i = first_pt + seg;
    const int j = (i + 1 < points_count) ? (i + 1) : first_pt;
    const float x3 = points[i * 2];
    const float y3 = points[i * 2 + 1];
    const float x4 = points[j * 2];
    const float y4 = points[j * 2 + 1];
 
    // Compute the intersection of the ray with the segment.
    const float dx = x4 - x3;
    const float dy = y4 - y3;
    const float det = dx * (-dir_y) + dy * dir_x;
    if(det > -1e-8f && det < 1e-8f) continue;
    const float inv_det = 1.0f / det;
 
    const float segment_param = ((ray2_x - x3) * (-dir_y) + (ray2_y - y3) * dir_x) * inv_det;
    const float ray_param = ((x3 - ray2_x) * dy - (y3 - ray2_y) * dx) * inv_det;
    if(segment_param < 0.0f || segment_param > 1.0f || ray_param <= 0.0f || ray_param >= min_s) continue;
 
    min_s = ray_param;
    const float ix = ray2_x + ray_param * dir_x;
    const float iy = ray2_y + ray_param * dir_y;
 
    // Offset along the ray axis toward the ray segment center.
    const float to_center = (ray_center_x - ix) * ux + (ray_center_y - iy) * uy;
    const float side_sign = (to_center >= 0.0f) ? 1.0f : -1.0f;
    result[0] = ix + side_sign * offset * ux;
    result[1] = iy + side_sign * offset * uy;
  }
}
 
void dt_masks_draw_source(cairo_t *cr, dt_masks_form_gui_t *mask_gui, const int form_index,
                          const int node_count, const float zoom_scale,
                          struct dt_masks_gui_center_point_t *center_point,
                          const shape_draw_function_t *draw_shape_func)
{
  if(IS_NULL_PTR(mask_gui)) return;
  dt_masks_form_gui_points_t *gui_points
      = (dt_masks_form_gui_points_t *)g_list_nth_data(mask_gui->points, form_index);
  if(IS_NULL_PTR(gui_points)) return;
 
  if(!mask_gui->creation)
  {
    const float main[2] = { center_point->main.x, center_point->main.y };
    const float source[2] = { center_point->source.x, center_point->source.y };
    const gboolean is_open_shape = (mask_gui->type & DT_MASKS_IS_OPEN_SHAPE) != 0;
    const gboolean is_closed_shape = (mask_gui->type & DT_MASKS_IS_CLOSED_SHAPE) != 0;
 
    int first_point_index = 2;
    if((mask_gui->type & DT_MASKS_ELLIPSE) != 0)
      first_point_index = 10;
    else if((mask_gui->type & DT_MASKS_IS_PATH_SHAPE) != 0)
      first_point_index = node_count * 3;
 
    int attach_points_count = gui_points->points_count;
    int attach_source_count = gui_points->source_count;
    if((mask_gui->type & DT_MASKS_BRUSH) != 0)
    {
      attach_points_count /= 2;
      attach_source_count /= 2;
    }
 
    float head[2] = { 0.0f, 0.0f };
    float tail[2] = { 0.0f, 0.0f };
 
    // Find attachment point for the arrow's head with the main shape
    _dt_masks_find_best_attachment_point(main, source, gui_points->points, attach_points_count,
                                         zoom_scale, first_point_index, is_closed_shape, 1.f, head);
 
    // Find attachment point for the arrow's base with the source shape
    _dt_masks_find_best_attachment_point(source, main, gui_points->source, attach_source_count,
                                         zoom_scale, first_point_index, is_closed_shape, 0.5f, tail);
 
    const gboolean selected = (mask_gui->group_selected == form_index)
                              && (mask_gui->source_selected || mask_gui->source_dragging);
    gboolean draw_tail = TRUE;
 
    // Do not draw the arrow tail if the shape overlapes source,
    // Just draw the head pointing to the center of the source shape
    // and displace it at mid-distance between main and source center.
    // Open shapes always draw the tail since they have not really filled area.
    if(is_closed_shape)
    {
      // From more frequent to least frequent, to get out of loop earlier. Tail first, then source.
      const float pts[4] = { tail[0], tail[1], source[0], source[1] };
      gboolean overlap = (dt_masks_point_in_form_exact(pts, 2, gui_points->points, first_point_index,
                                                       gui_points->points_count) >= 0);
      // Skip the second containment test when overlap is already detected.
      if(!overlap)
      {
        const float origin_pt[2] = { main[0], main[1] };
        overlap = (dt_masks_point_in_form_exact(origin_pt, 1, gui_points->source, first_point_index,
                                                gui_points->source_count) >= 0);
      }
 
      // Update head position to be between main and source center point.
      if(overlap)
      {
        head[0] = 0.5f * (main[0] + source[0]);
        head[1] = 0.5f * (main[1] + source[1]);
      }
 
      const float arrow_len_sq = sqf(tail[0] - head[0]) + sqf(tail[1] - head[1]);
      draw_tail = arrow_len_sq > 1e-6f && !overlap;
    }
 
    // Calculate the angle, so the arrow head always points in the direction of the main shape's center.
    const float angle = is_open_shape ? atan2f(tail[1] - head[1], tail[0] - head[0])
                                      : atan2f(head[1] - main[1], head[0] - main[0]);
 
    dt_draw_arrow(cr, zoom_scale, selected, draw_tail, DT_MASKS_DASH_ROUND, head, tail, angle);
 
 
 
    
    if(darktable.unmuted & DT_DEBUG_MASKS)
    {
      // Debug: show the main and source gravity points, show head and tail points
      cairo_save(cr);
      cairo_arc(cr, main[0], main[1], DT_PIXEL_APPLY_DPI(4.0f) / zoom_scale, 0, 2 * M_PI);
      cairo_set_source_rgba(cr, 1.0, 0.0, 0.0, 1);
      cairo_fill(cr);
      cairo_arc(cr, source[0], source[1], DT_PIXEL_APPLY_DPI(4.0f) / zoom_scale, 0, 2 * M_PI);
      cairo_set_source_rgba(cr, 0.0, 1.0, 0.0, 1);
      cairo_fill(cr);
 
      cairo_arc(cr, head[0], head[1], DT_PIXEL_APPLY_DPI(4.0f) / zoom_scale, 0, 2 * M_PI);
      cairo_set_source_rgba(cr, 0.0, 0.0, 1.0, 1);
      cairo_fill(cr);
      cairo_arc(cr, tail[0], tail[1], DT_PIXEL_APPLY_DPI(4.0f) / zoom_scale, 0, 2 * M_PI);
      cairo_fill(cr);
      cairo_restore(cr);
    }
  }
 
  // draw the source shape
  // Trick to draw the current polygon shape lines while editing, but draw the complete shape in all other cases
  const int rendered_node_count = node_count + !mask_gui->creation;
  const gboolean shape_selected = (mask_gui->group_selected == form_index)
                                  && (mask_gui->form_selected || mask_gui->form_dragging);
 
  dt_draw_source_shape(cr, zoom_scale, shape_selected, gui_points->source, gui_points->source_count,
                       rendered_node_count, draw_shape_func);
  
}
 
void dt_masks_draw_path_seg_by_seg(cairo_t *cr, dt_masks_form_gui_t *mask_gui, const int form_index,
                                   const float *points, const int points_count, const int node_count,
                                   const float zoom_scale)
{
  if(IS_NULL_PTR(cr) || IS_NULL_PTR(points) || IS_NULL_PTR(mask_gui)) return;
  if(node_count <= 0 || points_count <= node_count * 3 + 6) return;
 
  const int total_coords = points_count * 2;
  if(total_coords <= (node_count * 6 + 1)) return;
 
  const gboolean group_selected = (mask_gui->group_selected == form_index);
 
  int show_segment_index = 1;
  int current_segment_index = 0;
  cairo_move_to(cr, points[node_count * 6], points[node_count * 6 + 1]);
 
  for(int point_index = node_count * 3; point_index < points_count; point_index++)
  {
    const int coord_index = point_index * 2;
    if((coord_index + 1) >= total_coords) break;
 
    const double coord_x = points[coord_index];
    const double coord_y = points[coord_index + 1];
    cairo_line_to(cr, coord_x, coord_y);
 
    const int segment_coord_index = show_segment_index * 6;
    if((segment_coord_index + 3) >= total_coords) continue;
 
    const double segment_x = points[segment_coord_index + 2];
    const double segment_y = points[segment_coord_index + 3];
    if(coord_x == segment_x && coord_y == segment_y)
    {
      const gboolean seg_is_selected = group_selected
                                       && (dt_masks_gui_selected_segment_index(mask_gui)
                                           == current_segment_index);
      const gboolean all_selected = group_selected
                                    && dt_masks_is_anything_selected(mask_gui)
                                    && (mask_gui->form_selected || mask_gui->form_dragging);
 
      if(mask_gui->creation && current_segment_index == node_count - 2)
        dt_draw_stroke_line(DT_MASKS_DASH_ROUND, FALSE, cr, all_selected, zoom_scale, CAIRO_LINE_CAP_ROUND);
      else
        dt_draw_stroke_line(DT_MASKS_NO_DASH, FALSE, cr, (seg_is_selected || all_selected), zoom_scale,
                            CAIRO_LINE_CAP_BUTT);
 
      show_segment_index = (show_segment_index + 1) % node_count;
      current_segment_index++;
    }
 
    if(mask_gui->creation && current_segment_index >= node_count - 1) break;
  } 
}
 
static void _masks_draw_creation_session_forms(dt_develop_t *develop, dt_iop_module_t *module,
                                               cairo_t *cr, const float zoom_scale,
                                               const dt_masks_form_gui_t *creation_gui)
{
  if(!creation_gui->creation || IS_NULL_PTR(creation_gui->creation_formids)) return;
 
  dt_masks_form_gui_t draw_gui;
  dt_masks_init_form_gui(&draw_gui);
  draw_gui.edit_mode = creation_gui->edit_mode;
  draw_gui.group_selected = -1;
  draw_gui.pipe_hash = DT_PIXELPIPE_CACHE_HASH_INVALID;
 
  // Iterate over the ids saved in this creation session. Other masks stay
  // hidden while creation is active, even if they belong to the same module.
  for(GList *formid_node = creation_gui->creation_formids; formid_node; formid_node = g_list_next(formid_node))
  {
    const int formid = GPOINTER_TO_INT(formid_node->data);
    dt_masks_form_t *session_form = dt_masks_get_from_id(develop, formid);
    if(IS_NULL_PTR(session_form)) continue;
 
    dt_masks_gui_form_test_create(session_form, &draw_gui, module);
    if(session_form->functions && session_form->functions->post_expose)
    {
      const guint point_count = g_list_length(session_form->points);
      draw_gui.type = session_form->type;
      session_form->functions->post_expose(cr, zoom_scale, &draw_gui, 0, point_count);
    }
 
    // Keep the saved-session shape path from being connected to the active
    // creation cursor drawn right after this loop.
    cairo_new_path(cr);
    g_list_free_full(draw_gui.points, dt_masks_form_gui_points_free);
    draw_gui.points = NULL;
    draw_gui.pipe_hash = DT_PIXELPIPE_CACHE_HASH_INVALID;
    draw_gui.formid = 0;
  }
}
 
void dt_masks_events_post_expose(struct dt_iop_module_t *module, cairo_t *cr, int32_t width, int32_t height,
                                 int32_t pointerx, int32_t pointery)
{
  dt_develop_t *develop = darktable.develop;
  if(IS_NULL_PTR(develop)) return;
  dt_masks_form_t *mask_form = dt_masks_get_visible_form(develop);
  dt_masks_form_gui_t *mask_gui = develop->form_gui;
  if(IS_NULL_PTR(mask_gui)) return;
  if(IS_NULL_PTR(mask_form)) return;
 
  int buffer_width = 0;
  int buffer_height = 0;
  dt_dev_get_processed_size(develop, &buffer_width, &buffer_height);
 
  if(buffer_width < 1.0 || buffer_height < 1.0) return;
  const float zoom_scale = dt_dev_get_zoom_level(develop);
 
  // Create a surface to draw the mask, so that we can apply
  // operation that does not affect the main context
  cairo_surface_t *overlay = NULL;
  cairo_t *mask_draw = NULL;
  cairo_surface_t *target = cairo_get_target(cr);
  double sx = 1.0, sy = 1.0;
  cairo_surface_get_device_scale(target, &sx, &sy);
  overlay = cairo_surface_create_similar(target, CAIRO_CONTENT_COLOR_ALPHA, (int)ceil(width * sx),
                                         (int)ceil(height * sy));
  cairo_surface_set_device_scale(overlay, sx, sy);
  mask_draw = cairo_create(overlay);
 
  // Apply the same transformation to the mask drawing context
  /*cairo_matrix_t m;
  cairo_get_matrix(cr, &m);
  cairo_set_matrix(mask_draw, &m);*/
  
  cairo_save(mask_draw);
 
  // We rescale to input space
  if(dt_dev_rescale_roi_to_input(develop, mask_draw, width, height))
  {
    cairo_restore(mask_draw);
    cairo_destroy(mask_draw);
    cairo_surface_destroy(overlay);
    return;
  }
 
  // We update the form if needed
  // Add preview when creating a circle, ellipse and gradient
  if(!((mask_form->type & DT_MASKS_IS_PRIMITIVE_SHAPE) && mask_gui->creation))
    dt_masks_gui_form_test_create(mask_form, mask_gui, module);
 
  _masks_draw_creation_session_forms(develop, module, mask_draw, zoom_scale, mask_gui);
 
  // Draw form
  if(mask_form->type & DT_MASKS_GROUP)
    dt_group_events_post_expose(mask_draw, zoom_scale, mask_form, mask_gui);
  else if(mask_form->functions && mask_form->functions->post_expose)
  {
    const guint point_count = g_list_length(mask_form->points);
    mask_gui->type = mask_form->type;
    mask_form->functions->post_expose(mask_draw, zoom_scale, mask_gui, 0, point_count);
  }
  cairo_restore(mask_draw);
 
  // Draw the overlay with the same transformation as the main context
  cairo_save(cr);
  cairo_identity_matrix(cr);
  cairo_set_source_surface(cr, overlay, 0.0, 0.0);
  cairo_paint(cr);
  cairo_restore(cr);
 
  cairo_destroy(mask_draw);
  cairo_surface_destroy(overlay);
}
 
void dt_masks_clear_form_gui(dt_develop_t *develop)
{
  if(IS_NULL_PTR(develop->form_gui)) return;
  g_list_free_full(develop->form_gui->points, dt_masks_form_gui_points_free);
  develop->form_gui->points = NULL;
  dt_masks_dynbuf_free(develop->form_gui->guipoints);
  develop->form_gui->guipoints = NULL;
  dt_masks_dynbuf_free(develop->form_gui->guipoints_payload);
  develop->form_gui->guipoints_payload = NULL;
  develop->form_gui->guipoints_count = 0;
  develop->form_gui->pipe_hash = DT_PIXELPIPE_CACHE_HASH_INVALID;
  develop->form_gui->formid = 0;
  develop->form_gui->delta[0] = develop->form_gui->delta[1] = 0.0f;
  develop->form_gui->scrollx = develop->form_gui->scrolly = 0.0f;
  develop->form_gui->form_selected = develop->form_gui->border_selected = develop->form_gui->form_dragging
      = develop->form_gui->form_rotating = develop->form_gui->border_toggling = develop->form_gui->gradient_toggling = FALSE;
  develop->form_gui->source_selected = develop->form_gui->source_dragging = FALSE;
  develop->form_gui->pivot_selected = FALSE;
  develop->form_gui->node_hovered = -1;
  develop->form_gui->handle_hovered = -1;
  develop->form_gui->seg_hovered = -1;
  develop->form_gui->handle_border_hovered = -1;
  develop->form_gui->node_selected = FALSE;
  develop->form_gui->handle_selected = FALSE;
  develop->form_gui->seg_selected = FALSE;
  develop->form_gui->handle_border_selected = FALSE;
  develop->form_gui->node_selected_idx = -1;
  develop->form_gui->handle_border_dragging = develop->form_gui->seg_dragging = develop->form_gui->handle_dragging
      = develop->form_gui->node_dragging = -1;
  develop->form_gui->creation_closing_form = FALSE;
  dt_masks_creation_mode_quit(develop->form_gui);
  develop->form_gui->pressure_sensitivity = DT_MASKS_PRESSURE_OFF;
  develop->form_gui->creation_module = NULL;
  develop->form_gui->creation_type = DT_MASKS_NONE;
  g_list_free(develop->form_gui->creation_formids);
  develop->form_gui->creation_formids = NULL;
  develop->form_gui->creation_last_formid = 0;
  develop->form_gui->node_selected = FALSE;
 
  develop->form_gui->group_selected = -1;
  develop->form_gui->group_selected = -1;
  develop->form_gui->edit_mode = DT_MASKS_EDIT_OFF;
  develop->form_gui->last_rebuild_ts = 0.0;
  develop->form_gui->last_rebuild_pos[0] = develop->form_gui->last_rebuild_pos[1] = 0.0f;
  develop->form_gui->rebuild_pending = FALSE;
  develop->form_gui->last_hit_test_pos[0] = develop->form_gui->last_hit_test_pos[1] = -1.0f;
  // allow to select a shape inside an iop
  dt_masks_select_form(NULL, NULL);
}
 
void dt_masks_change_form_gui(dt_masks_form_t *new_form)
{
  dt_masks_form_t *old_form = dt_masks_get_visible_form(darktable.develop);
  if(!IS_NULL_PTR(old_form))
  {
    gboolean is_registered = FALSE;
    gboolean is_registered_for_cleanup = FALSE;
    dt_pthread_rwlock_rdlock(&darktable.develop->masks_mutex);
    for(const GList *form_node = darktable.develop->forms; form_node; form_node = g_list_next(form_node))
    {
      if(form_node->data == old_form)
      {
        is_registered = TRUE;
        break;
      }
    }
 
    for(const GList *form_node = darktable.develop->allforms; form_node; form_node = g_list_next(form_node))
    {
      if(form_node->data == old_form)
      {
        is_registered_for_cleanup = TRUE;
        break;
      }
    }
    dt_pthread_rwlock_unlock(&darktable.develop->masks_mutex);
 
    // Free only fully orphan temporary previews. Forms tracked in either list
    // are owned by develop and will be released by its teardown path.
    if(!is_registered && !is_registered_for_cleanup) dt_masks_free_form(old_form);
  }
 
  dt_masks_clear_form_gui(darktable.develop);
  dt_masks_set_visible_form(darktable.develop, new_form);
}
 
void dt_masks_reset_form_gui(void)
{
  dt_masks_change_form_gui(NULL);
  dt_masks_shape_buttons_deactivate_all(NULL);
  dt_iop_module_t *module = darktable.develop->gui_module;
  if(!IS_NULL_PTR(module) && (module->flags() & IOP_FLAGS_SUPPORTS_BLENDING) && !(module->flags() & IOP_FLAGS_NO_MASKS)
    && !IS_NULL_PTR(module->blend_data))
  {
    dt_iop_gui_blend_data_t *blend_data = (dt_iop_gui_blend_data_t *)module->blend_data;
    blend_data->masks_shown = DT_MASKS_EDIT_OFF;
    if(!IS_NULL_PTR(blend_data->masks_edit))
      gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(blend_data->masks_edit), 0);
  }
}
 
void dt_masks_reset_show_masks_icons(void)
{
  dt_masks_shape_buttons_deactivate_all(NULL);
  for(GList *module_node = darktable.develop->iop; module_node; module_node = g_list_next(module_node))
  {
    dt_iop_module_t *module = (dt_iop_module_t *)module_node->data;
    if(module && (module->flags() & IOP_FLAGS_SUPPORTS_BLENDING) && !(module->flags() & IOP_FLAGS_NO_MASKS)
    && !IS_NULL_PTR(module->blend_data))
    {
      dt_iop_gui_blend_data_t *blend_data = (dt_iop_gui_blend_data_t *)module->blend_data;
      blend_data->masks_shown = DT_MASKS_EDIT_OFF;
      if(!IS_NULL_PTR(blend_data->masks_edit))
      {
        gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(blend_data->masks_edit), FALSE);
        gtk_widget_queue_draw(blend_data->masks_edit);
      }
    }
  }
}
 
dt_masks_edit_mode_t dt_masks_get_edit_mode(struct dt_iop_module_t *module)
{
  return darktable.develop->form_gui
    ? darktable.develop->form_gui->edit_mode
    : DT_MASKS_EDIT_OFF;
}
 
void dt_masks_set_edit_mode(struct dt_iop_module_t *module, dt_masks_edit_mode_t value)
{
  if(IS_NULL_PTR(module)) return;
  dt_iop_gui_blend_data_t *blend_data = (dt_iop_gui_blend_data_t *)module->blend_data;
  if(IS_NULL_PTR(blend_data)) return;
 
  dt_masks_form_t *group_form = NULL;
  dt_masks_form_t *mask_form = dt_masks_get_from_id(module->dev, module->blend_params->mask_id);
  if(value && !IS_NULL_PTR(mask_form))
  {
    group_form = dt_masks_create_ext(DT_MASKS_GROUP);
    group_form->formid = 0;
    dt_masks_group_ungroup(group_form, mask_form);
  }
 
  if(blend_data) blend_data->masks_shown = value;
 
  dt_masks_change_form_gui(group_form);
  darktable.develop->form_gui->edit_mode = value;
  if(value && mask_form)
    dt_dev_masks_selection_change(darktable.develop, NULL, mask_form->formid, FALSE);
  else
    dt_dev_masks_selection_change(darktable.develop, NULL, 0, FALSE);
 
  if(blend_data->masks_support)
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(blend_data->masks_edit),
                                 value == DT_MASKS_EDIT_OFF ? FALSE : TRUE);
 
  dt_control_queue_redraw_center();
}
 
static void _menu_no_masks(struct dt_iop_module_t *module)
{
  // we drop all the forms in the iop
  dt_masks_form_t *group_form = _group_from_module(darktable.develop, module);
  if(group_form) dt_masks_form_delete(module, NULL, group_form);
  module->blend_params->mask_id = 0;
 
  // and we update the iop
  dt_masks_set_edit_mode(module, DT_MASKS_EDIT_OFF);
  dt_masks_iop_update(module);
}
 
static void _menu_add_shape(struct dt_iop_module_t *module, dt_masks_type_t type)
{
  dt_masks_creation_mode_enter(module, type);
}
 
static void _menu_add_exist(dt_iop_module_t *module, int form_id)
{
  if(IS_NULL_PTR(module)) return;
  dt_masks_form_t *mask_form = dt_masks_get_from_id(darktable.develop, form_id);
  if(IS_NULL_PTR(mask_form)) return;
 
  // is there already a masks group for this module ?
  dt_masks_form_t *group_form = _group_from_module(darktable.develop, module);
  if(IS_NULL_PTR(group_form))
  {
    group_form = _group_create(darktable.develop, module, DT_MASKS_GROUP);
  }
  // we add the form in this group
  dt_masks_group_add_form(group_form, mask_form);
  // we save the group
  // and we ensure that we are in edit mode
 
  dt_masks_iop_update(module);
  dt_masks_set_edit_mode(module, DT_MASKS_EDIT_FULL);
}
 
void dt_masks_group_update_name(dt_iop_module_t *module)
{
  dt_masks_form_t *group_form = _group_from_module(darktable.develop, module);
  if (IS_NULL_PTR(group_form))
    return;
 
  _set_group_name_from_module(module, group_form);
 
  dt_masks_iop_update(module);
}
 
void dt_masks_iop_use_same_as(dt_iop_module_t *module, dt_iop_module_t *source_module)
{
  if(IS_NULL_PTR(module) || IS_NULL_PTR(source_module)) return;
 
  // we get the source group
  int source_id = source_module->blend_params->mask_id;
  dt_masks_form_t *source_group = dt_masks_get_from_id(darktable.develop, source_id);
  if(IS_NULL_PTR(source_group) || source_group->type != DT_MASKS_GROUP) return;
 
  // is there already a masks group for this module ?
  dt_masks_form_t *group_form = _group_from_module(darktable.develop, module);
  if(IS_NULL_PTR(group_form))
  {
    group_form = _group_create(darktable.develop, module, DT_MASKS_GROUP);
  }
  // we copy the src group in this group
  for(GList *group_node = source_group->points; group_node; group_node = g_list_next(group_node))
  {
    dt_masks_form_group_t *group_entry = (dt_masks_form_group_t *)group_node->data;
    dt_masks_form_t *mask_form = dt_masks_get_from_id(darktable.develop, group_entry->formid);
    if(mask_form)
    {
      dt_masks_form_group_t *new_entry = dt_masks_group_add_form(group_form, mask_form);
      if(new_entry)
      {
        new_entry->state = group_entry->state;
        new_entry->opacity = group_entry->opacity;
      }
    }
  }
 
  // we save the group
 
}
 
void dt_masks_iop_combo_populate(GtkWidget *widget, void *data)
{
  // we ensure that the module has focus
  dt_iop_module_t *module = (dt_iop_module_t *)data;
  dt_iop_request_focus(module);
  dt_iop_gui_blend_data_t *blend_data = (dt_iop_gui_blend_data_t *)module->blend_data;
 
  // we determine a higher approx of the entry number
  const guint forms_count = g_list_length(module->dev->forms);
  const guint iop_count = g_list_length(module->dev->iop);
  guint combo_capacity = 5 + forms_count + iop_count;
  dt_free(blend_data->masks_combo_ids);
  blend_data->masks_combo_ids = malloc(sizeof(int) * combo_capacity);
 
  int *combo_ids = blend_data->masks_combo_ids;
  GtkWidget *combo = blend_data->masks_combo;
 
  // we remove all the combo entries except the first one
  while(dt_bauhaus_combobox_length(combo) > 1)
  {
    dt_bauhaus_combobox_remove_at(combo, 1);
  }
 
  int combo_index = 0;
  combo_ids[combo_index] = 0; // nothing to do for the first entry (already here)
  combo_index++;
 
  // add existing shapes
  dt_pthread_rwlock_rdlock(&module->dev->masks_mutex);
  for(GList *form_node = module->dev->forms; form_node; form_node = g_list_next(form_node))
  {
    dt_masks_form_t *mask_form = (dt_masks_form_t *)form_node->data;
    if((mask_form->type & (DT_MASKS_CLONE|DT_MASKS_NON_CLONE))
       || mask_form->formid == module->blend_params->mask_id)
    {
      continue;
    }
 
    // we search were this form is used in the current module
    int is_used = 0;
    dt_masks_form_t *group_form = _group_from_module(module->dev, module);
    if(group_form && (group_form->type & DT_MASKS_GROUP))
    {
      for(GList *group_node = group_form->points; group_node; group_node = g_list_next(group_node))
      {
        dt_masks_form_group_t *group_entry = (dt_masks_form_group_t *)group_node->data;
        if(group_entry->formid == mask_form->formid)
        {
          is_used = 1;
          break;
        }
      }
    }
    if(!is_used)
    {
      dt_bauhaus_combobox_add(combo, mask_form->name);
      combo_ids[combo_index] = mask_form->formid;
      combo_index++;
    }
  }
  dt_pthread_rwlock_unlock(&module->dev->masks_mutex);
 
  // masks from other iops
  int iop_index = 1;
  for(GList *module_node = module->dev->iop; module_node; module_node = g_list_next(module_node))
  {
    dt_iop_module_t *other_module = (dt_iop_module_t *)module_node->data;
    if((other_module != module) && (other_module->flags() & IOP_FLAGS_SUPPORTS_BLENDING)
       && !(other_module->flags() & IOP_FLAGS_NO_MASKS))
    {
      dt_masks_form_t *group_form = _group_from_module(darktable.develop, other_module);
      if(group_form)
      {
        gchar *module_label = dt_history_item_get_name(other_module);
        dt_bauhaus_combobox_add(combo, g_strdup_printf(_("reuse shapes from %s"), module_label));
        dt_free(module_label);
        combo_ids[combo_index] = -1 * iop_index;
        combo_index++;
      }
    }
    iop_index++;
  }
}
 
void dt_masks_iop_value_changed_callback(GtkWidget *widget, struct dt_iop_module_t *module)
{
  // we get the corresponding value
  dt_iop_gui_blend_data_t *blend_data = (dt_iop_gui_blend_data_t *)module->blend_data;
 
  int selection_index = dt_bauhaus_combobox_get(blend_data->masks_combo);
  if(selection_index == 0) return;
  if(selection_index > 0)
  {
    int selection_value = blend_data->masks_combo_ids[selection_index];
    const guint iop_count = g_list_length(module->dev->iop);
    // FIXME : these values should use binary enums
    if(selection_value == -1000000)
    {
      // delete all masks
      _menu_no_masks(module);
    }
    else if(selection_value == -2000001)
    {
      // add a circle shape
      _menu_add_shape(module, DT_MASKS_CIRCLE);
    }
    else if(selection_value == -2000002)
    {
      // add a path shape
      _menu_add_shape(module, DT_MASKS_POLYGON);
    }
    else if(selection_value == -2000016)
    {
      // add a gradient shape
      _menu_add_shape(module, DT_MASKS_GRADIENT);
    }
    else if(selection_value == -2000032)
    {
      // add a gradient shape
      _menu_add_shape(module, DT_MASKS_ELLIPSE);
    }
    else if(selection_value == -2000064)
    {
      // add a brush shape
      _menu_add_shape(module, DT_MASKS_BRUSH);
    }
    else if(selection_value < 0)
    {
      // use same shapes as another iop
      selection_value = -1 * selection_value - 1;
      if(selection_value < (int)iop_count)
      {
        dt_iop_module_t *source_module
            = (dt_iop_module_t *)g_list_nth_data(module->dev->iop, selection_value);
        dt_masks_iop_use_same_as(module, source_module);
        // and we ensure that we are in edit mode
        //
 
        dt_masks_set_edit_mode(module, DT_MASKS_EDIT_FULL);
      }
    }
    else if(selection_value > 0)
    {
      // add an existing shape
      _menu_add_exist(module, selection_value);
    }
    else
      return;
  }
  // we update the combo line
  dt_masks_iop_update(module);
  dt_dev_add_history_item(module->dev, module, TRUE, TRUE);
}
 
void dt_masks_form_delete(struct dt_iop_module_t *module, dt_masks_form_t *group_form,
                          dt_masks_form_t *mask_form)
{
  if(IS_NULL_PTR(mask_form)) return;
  int form_id = mask_form->formid;
  if(!IS_NULL_PTR(group_form) && !(group_form->type & DT_MASKS_GROUP)) return;
 
  if(!(mask_form->type & (DT_MASKS_CLONE | DT_MASKS_NON_CLONE)) && !IS_NULL_PTR(group_form))
  {
    // we try to remove the form from the masks group
    int removed = 0;
    for(GList *group_node = group_form->points; group_node; group_node = g_list_next(group_node))
    {
      dt_masks_form_group_t *group_entry = (dt_masks_form_group_t *)group_node->data;
      if(group_entry->formid == form_id)
      {
        removed = 1;
        group_form->points = g_list_remove(group_form->points, group_entry);
        dt_free(group_entry);
        break;
      }
    }
    if(removed)
    if(removed && !IS_NULL_PTR(module))
    {
      dt_masks_iop_update(module);
 
    }
    if(removed) dt_masks_form_update_gravity_center(group_form);
    if(removed && IS_NULL_PTR(group_form->points)) dt_masks_form_delete(module, NULL, group_form);
    return;
  }
 
  if(mask_form->type & DT_MASKS_GROUP && mask_form->type & DT_MASKS_CLONE)
  {
    // when removing a cloning group the children have to be removed, too, as they won't be shown in the mask manager
    // and are thus not accessible afterwards.
    while(mask_form->points)
    {
      dt_masks_form_group_t *group_child = (dt_masks_form_group_t *)mask_form->points->data;
      dt_masks_form_t *child = dt_masks_get_from_id(darktable.develop, group_child->formid);
      dt_masks_form_delete(module, mask_form, child);
      // no need to do anything to mask_form->points, the recursive call will have removed child from the list
    }
  }
 
  // if we are here that mean we have to permanently delete this form
  // we drop the form from all modules
  for(GList *iop_node = darktable.develop->iop; iop_node; iop_node = g_list_next(iop_node))
  {
    dt_iop_module_t *iop_module = (dt_iop_module_t *)iop_node->data;
    if(iop_module->flags() & IOP_FLAGS_SUPPORTS_BLENDING)
    {
      // is the form the base group of the iop ?
      if(form_id == iop_module->blend_params->mask_id)
      {
        iop_module->blend_params->mask_id = 0;
        dt_masks_iop_update(iop_module);
      }
      else
      {
        dt_masks_form_t *iop_group = _group_from_module(darktable.develop, iop_module);
        if(iop_group && (iop_group->type & DT_MASKS_GROUP))
        {
          int removed = 0;
          GList *shapes = iop_group->points;
          while(shapes)
          {
            dt_masks_form_group_t *group_entry = (dt_masks_form_group_t *)shapes->data;
            if(group_entry->formid == form_id)
            {
              removed = 1;
              // Remove the shape from the list
              iop_group->points = g_list_remove(iop_group->points, group_entry);
              dt_free(group_entry);
              shapes = iop_group->points; // jump back to start of list
              continue;
            }
            shapes = g_list_next(shapes); // advance to next form
          }
          if(removed)
          {
            dt_masks_iop_update(iop_module);
 
            if(IS_NULL_PTR(iop_group->points)) dt_masks_form_delete(iop_module, NULL, iop_group);
          }
        }
      }
    }
  }
  // we drop the form from the general list
  for(GList *form_node = darktable.develop->forms; form_node; form_node = g_list_next(form_node))
  {
    dt_masks_form_t *existing_form = (dt_masks_form_t *)form_node->data;
    if(existing_form->formid == form_id)
    {
      dt_masks_remove_form(darktable.develop, existing_form);
      break;
    }
  }
}
 
float dt_masks_form_get_interaction_value(dt_masks_form_group_t *form_group,
                                          dt_masks_interaction_t interaction)
{
  if(IS_NULL_PTR(form_group)) return NAN;
 
  if(interaction == DT_MASKS_INTERACTION_OPACITY)
  {
    return form_group->opacity;
  }
 
  dt_masks_form_t *target_form = dt_masks_get_from_id(darktable.develop, form_group->formid);
  if(IS_NULL_PTR(target_form) || IS_NULL_PTR(target_form->functions) || IS_NULL_PTR(target_form->functions->get_interaction_value)) return NAN;
 
  return target_form->functions->get_interaction_value(target_form, interaction);
}
 
gboolean dt_masks_form_get_gravity_center(const dt_masks_form_t *mask_form, float center[2], float *area)
{
  center[0] = 0.0f;
  center[1] = 0.0f;
  if(!IS_NULL_PTR(area)) *area = 0.0f;
 
  if(IS_NULL_PTR(mask_form) || IS_NULL_PTR(mask_form->functions) || IS_NULL_PTR(mask_form->functions->get_gravity_center) || IS_NULL_PTR(center)) return FALSE;
  return mask_form->functions->get_gravity_center(mask_form, center, area);
}
 
void dt_masks_form_update_gravity_center(dt_masks_form_t *mask_form)
{
  if(IS_NULL_PTR(mask_form)) return;
 
  float center_point[2];
  float area = 0.0f;
  const gboolean ok = dt_masks_form_get_gravity_center(mask_form, center_point, &area);
  mask_form->gravity_center[0] = center_point[0];
  mask_form->gravity_center[1] = center_point[1];
  mask_form->area = area;
 
  dt_print(DT_DEBUG_MASKS,
           "[masks] gravity center updated: form=%p id=%d type=0x%x ok=%d center=(%f,%f), area=%f\n",
           (void *)mask_form, mask_form->formid, mask_form->type, ok,
           mask_form->gravity_center[0], mask_form->gravity_center[1], mask_form->area);
}
 
int dt_masks_center_view_on_form(dt_develop_t *dev, const dt_masks_form_t *mask_form)
{
  if(IS_NULL_PTR(dev) || IS_NULL_PTR(mask_form)) return 1;
 
  float center[2] = { 0.0f, 0.0f };
  float area = 0.0f;
  if(!dt_masks_form_get_gravity_center(mask_form, center, &area)) return 1;
 
  dt_dev_coordinates_raw_norm_to_raw_abs(dev, center, 1);
  if(!dt_dev_coordinates_raw_abs_to_image_abs(dev, center, 1)) return 1;
  dt_dev_coordinates_image_abs_to_image_norm(dev, center, 1);
 
  dev->roi.x = center[0];
  dev->roi.y = center[1];
  dt_dev_check_zoom_pos_bounds(dev, &dev->roi.x, &dev->roi.y, NULL, NULL);
  dt_dev_pixelpipe_change_zoom_main(dev);
 
  return 0;
}
 
static float _change_opacity(dt_masks_form_group_t *form_group, float value,
                             const dt_masks_increment_t increment, const int flow)
{
  if(IS_NULL_PTR(form_group)) return 0;
 
  form_group->opacity = CLAMPF(dt_masks_apply_increment(form_group->opacity, value, increment, flow), 0.0f, 1.0f);
  dt_toast_log(_("Opacity: %3.2f%%"), form_group->opacity * 100.f);
  return form_group->opacity;
}
 
float dt_masks_form_set_interaction_value(dt_masks_form_group_t *form_group,
                                          dt_masks_interaction_t interaction,
                                          float value, dt_masks_increment_t increment, int flow,
                                          dt_masks_form_gui_t *mask_gui, dt_iop_module_t *module)
{
  if(IS_NULL_PTR(form_group)) return NAN;
 
  if(interaction == DT_MASKS_INTERACTION_OPACITY)
  {
    const float result = _change_opacity(form_group, value, increment, flow);
    return result;
  }
 
  dt_masks_form_t *target_form = dt_masks_get_from_id(darktable.develop, form_group->formid);
  if(IS_NULL_PTR(target_form) || !target_form->functions
     || !target_form->functions->set_interaction_value) return NAN;
 
  const float result = target_form->functions->set_interaction_value(target_form, interaction, value, increment,
                                                                     flow, mask_gui, module);
  if(isnan(result)) return NAN;
  dt_masks_form_update_gravity_center(target_form);
  //dt_dev_add_history_item(darktable.develop, module, TRUE, TRUE);
  return result;
}
 
const char * _get_mask_plugin(dt_masks_form_t *mask_form)
{
  // Internal masks are used by spots removal and retouch modules
  if(mask_form->type & (DT_MASKS_CLONE | DT_MASKS_NON_CLONE))
    return "spots";
  // Regular all-purpose masks
  else
    return "masks";
}
 
const char * _get_mask_type(dt_masks_form_t *mask_form)
{
  // warning: mask types or not int enum but bit flags ?!?
  // that's a shitty design that prevents us from doing a clean switch case over the enum.
  // why would we overlap mask types ?!?
  if(mask_form->type & DT_MASKS_CIRCLE)
    return "circle";
  else if(mask_form->type & DT_MASKS_POLYGON)
    return "polygon";
  else if(mask_form->type & DT_MASKS_ELLIPSE)
    return "ellipse";
  else if(mask_form->type & DT_MASKS_GRADIENT)
    return "gradient";
  else if(mask_form->type & DT_MASKS_BRUSH)
    return "brush";
  else
    return "unknown";
}
 
float dt_masks_apply_increment(float current, float amount, dt_masks_increment_t increment, int flow)
{
  switch(increment)
  {
    case DT_MASKS_INCREMENT_SCALE:
      return current * powf(amount, (float)flow);
    case DT_MASKS_INCREMENT_OFFSET:
      return current + amount * (float)flow;
    case DT_MASKS_INCREMENT_ABSOLUTE:
    default:
      return amount;
  }
}
 
float dt_masks_apply_increment_precomputed(float current, float amount, float scale_amount, float offset_amount,
                                           dt_masks_increment_t increment)
{
  switch(increment)
  {
    case DT_MASKS_INCREMENT_SCALE:
      return current * scale_amount;
    case DT_MASKS_INCREMENT_OFFSET:
      return current + offset_amount;
    case DT_MASKS_INCREMENT_ABSOLUTE:
    default:
      return amount;
  }
}
 
float dt_masks_get_set_conf_value(dt_masks_form_t *mask_form, char *feature, float new_value,
                                  float value_min, float value_max,
                                  dt_masks_increment_t increment, int flow)
{
  gchar *config_key = NULL;
  if(!strcmp(feature, "opacity"))
    config_key = g_strdup_printf("plugins/darkroom/%s_opacity", _get_mask_plugin(mask_form));
  else
    config_key = g_strdup_printf("plugins/darkroom/%s/%s/%s",
                                 _get_mask_plugin(mask_form), _get_mask_type(mask_form), feature);
 
  if(!g_strcmp0(feature, "rotation")) flow = (flow > 1) ? (flow - 1) * 5 : flow;
 
  const float current_value = dt_conf_get_float(config_key);
  float updated_value = dt_masks_apply_increment(current_value, new_value, increment, flow);
  if(!g_strcmp0(feature, "rotation"))
  {
    // Ensure the rotation value stays within the interval [min, max)
    if(updated_value > value_max) updated_value = fmodf(updated_value, value_max);
    else if(updated_value < value_min)
      updated_value = value_max - fmodf(value_min - updated_value, value_max);
  }
  else updated_value = MAX(value_min, MIN(updated_value, value_max));
 
  dt_conf_set_float(config_key, updated_value);
 
  dt_free(config_key);
  return updated_value;
}
 
float dt_masks_get_set_conf_value_with_toast(dt_masks_form_t *mask_form, const char *feature, float amount,
                                             float value_min, float value_max,
                                             dt_masks_increment_t increment, int flow,
                                             const char *toast_fmt, float toast_scale)
{
  float value = dt_masks_get_set_conf_value(mask_form, (char *)feature, amount,
                                            value_min, value_max, increment, flow);
  if(!IS_NULL_PTR(toast_fmt) && toast_fmt[0] != '\0')
    dt_toast_log(toast_fmt, value * toast_scale);
  return value;
}
 
void dt_masks_duplicate_points(const dt_masks_form_t *base_form, dt_masks_form_t *dest_form,
                               size_t node_size)
{
  if(IS_NULL_PTR(base_form) || IS_NULL_PTR(dest_form) || IS_NULL_PTR(base_form->points) || node_size == 0) return;
 
  for(const GList *point_node = base_form->points; point_node; point_node = g_list_next(point_node))
  {
    const void *point_data = point_node->data;
    if(IS_NULL_PTR(point_data)) continue;
    void *point_copy = malloc(node_size);
    if(IS_NULL_PTR(point_copy)) continue;
    memcpy(point_copy, point_data, node_size);
    dest_form->points = g_list_append(dest_form->points, point_copy);
  }
}
 
int dt_masks_form_change_opacity(dt_masks_form_t *mask_form, int parent_id, int scroll_up,
                                 const int flow)
{
  if(IS_NULL_PTR(mask_form)) return 0;
  dt_masks_form_group_t *form_group = dt_masks_form_group_from_parentid(parent_id, mask_form->formid);
  if(IS_NULL_PTR(form_group)) return 0;
 
  float amount = scroll_up ? 0.02f : -0.02f;
  const float changed = dt_masks_form_set_interaction_value(form_group, DT_MASKS_INTERACTION_OPACITY,
                                                            amount, DT_MASKS_INCREMENT_OFFSET, flow, NULL, NULL);
  return !isnan(changed);
}
 
void dt_masks_form_move(dt_masks_form_t *group_form, int form_id, int move_up)
{
  if(IS_NULL_PTR(group_form) || !(group_form->type & DT_MASKS_GROUP)) return;
 
  // we search the form in the group
  dt_masks_form_group_t *group_entry = NULL;
  guint group_index = 0;
  for(GList *group_node = group_form->points; group_node; group_node = g_list_next(group_node))
  {
    dt_masks_form_group_t *entry = (dt_masks_form_group_t *)group_node->data;
    if(entry->formid == form_id)
    {
      group_entry = entry;
      break;
    }
    group_index++;
  }
 
  // we remove the form and read it
  if(!IS_NULL_PTR(group_entry))
  {
    const guint group_length = g_list_length(group_form->points);
    if(!move_up && group_index == 0) return;
    if(move_up && group_index == group_length - 1) return;
 
    group_form->points = g_list_remove(group_form->points, group_entry);
    if(!move_up)
      group_index -= 1;
    else
      group_index += 1;
    group_form->points = g_list_insert(group_form->points, group_entry, group_index);
 
  }
}
 
static int _find_in_group(dt_masks_form_t *group_form, int form_id)
{
  if(!(group_form->type & DT_MASKS_GROUP)) return 0;
  if(group_form->formid == form_id) return 1;
  int nested_count = 0;
  for(GList *group_node = group_form->points; group_node; group_node = g_list_next(group_node))
  {
    const dt_masks_form_group_t *group_entry = (dt_masks_form_group_t *)group_node->data;
    dt_masks_form_t *mask_form = dt_masks_get_from_id(darktable.develop, group_entry->formid);
    if(mask_form)
    {
      if(mask_form->type & DT_MASKS_GROUP) nested_count += _find_in_group(mask_form, form_id);
    }
  }
  return nested_count;
}
 
dt_masks_form_group_t *dt_masks_group_add_form(dt_masks_form_t *group_form, dt_masks_form_t *mask_form)
{
  // add a form to group and check for self inclusion
 
  if(!(group_form->type & DT_MASKS_GROUP)) return NULL;
  // either the form to add is not a group, so no risk
  // or we go through all points of form to see if we find a ref to grp->formid
  if(!(mask_form->type & DT_MASKS_GROUP) || _find_in_group(mask_form, group_form->formid) == 0)
  {
    dt_masks_form_group_t *group_entry = malloc(sizeof(dt_masks_form_group_t));
    group_entry->formid = mask_form->formid;
    group_entry->parentid = group_form->formid;
    group_entry->state = DT_MASKS_STATE_SHOW | DT_MASKS_STATE_USE | DT_MASKS_STATE_UNION;
    group_entry->opacity = dt_conf_get_float("plugins/darkroom/masks/opacity");
    group_form->points = g_list_append(group_form->points, group_entry);
    dt_masks_form_update_gravity_center(group_form);
    return group_entry;
  }
 
  dt_control_log(_("Masks can not contain themselves"));
  return NULL;
}
 
void dt_masks_group_ungroup(dt_masks_form_t *dest_group, dt_masks_form_t *group_form)
{
  if(IS_NULL_PTR(group_form) || IS_NULL_PTR(dest_group)) return;
  if(!(group_form->type & DT_MASKS_GROUP) || !(dest_group->type & DT_MASKS_GROUP)) return;
 
  for(GList *group_node = group_form->points; group_node; group_node = g_list_next(group_node))
  {
    dt_masks_form_group_t *group_entry = (dt_masks_form_group_t *)group_node->data;
    dt_masks_form_t *mask_form = dt_masks_get_from_id(darktable.develop, group_entry->formid);
    if(mask_form)
    {
      if(mask_form->type & DT_MASKS_GROUP)
      {
        dt_masks_group_ungroup(dest_group, mask_form);
      }
      else
      {
        dt_masks_form_group_t *new_entry = (dt_masks_form_group_t *)malloc(sizeof(dt_masks_form_group_t));
        new_entry->formid = group_entry->formid;
        new_entry->parentid = group_entry->parentid;
        new_entry->state = group_entry->state;
        new_entry->opacity = group_entry->opacity;
        dest_group->points = g_list_append(dest_group->points, new_entry);
      }
    }
  }
 
  dt_masks_form_update_gravity_center(dest_group);
}
 
uint64_t dt_masks_group_get_hash(uint64_t hash, dt_masks_form_t *mask_form)
{
  if(IS_NULL_PTR(mask_form)) return hash;
 
  // basic infos
  hash = dt_hash(hash, (char *)&mask_form->type, sizeof(dt_masks_type_t));
  hash = dt_hash(hash, (char *)&mask_form->formid, sizeof(int));
  hash = dt_hash(hash, (char *)&mask_form->version, sizeof(int));
  hash = dt_hash(hash, (char *)&mask_form->source, sizeof(float) * 2);
 
  for(const GList *point_node = mask_form->points; point_node; point_node = g_list_next(point_node))
  {
    if(mask_form->type & DT_MASKS_GROUP)
    {
      dt_masks_form_group_t *group_entry = (dt_masks_form_group_t *)point_node->data;
      dt_masks_form_t *child_form = dt_masks_get_from_id(darktable.develop, group_entry->formid);
      if(child_form)
      {
        // state & opacity
        hash = dt_hash(hash, (char *)&group_entry->state, sizeof(int));
        hash = dt_hash(hash, (char *)&group_entry->opacity, sizeof(float));
 
        // the form itself
        hash = dt_masks_group_get_hash(hash, child_form);
      }
    }
    else if(mask_form->functions)
    {
      hash = dt_hash(hash, (char *)point_node->data, mask_form->functions->point_struct_size);
    }
  }
  return hash;
}
 
// adds formid to used array
// if formid is a group it adds all the forms that belongs to that group
static void _cleanup_unused_recurs(GList *form_list, int form_id, int *used_form_ids, int used_count)
{
  // first, we search for the formid in used table
  for(int used_index = 0; used_index < used_count; used_index++)
  {
    if(used_form_ids[used_index] == 0)
    {
      // we store the formid
      used_form_ids[used_index] = form_id;
      break;
    }
    if(used_form_ids[used_index] == form_id) break;
  }
 
  // if the form is a group, we iterate through the sub-forms
  dt_masks_form_t *mask_form = dt_masks_get_from_id_ext(form_list, form_id);
  if(!IS_NULL_PTR(mask_form) && (mask_form->type & DT_MASKS_GROUP))
  {
    for(GList *group_node = mask_form->points; group_node; group_node = g_list_next(group_node))
    {
      dt_masks_form_group_t *group_entry = (dt_masks_form_group_t *)group_node->data;
      _cleanup_unused_recurs(form_list, group_entry->formid, used_form_ids, used_count);
    }
  }
}
 
// removes from _forms all forms that are not used in history_list up to history_end
static int _masks_cleanup_unused(GList **forms_list, GList *history_list, const int history_end)
{
  int masks_removed = 0;
  GList *forms = *forms_list;
 
  // we create a table to store the ids of used forms
  guint form_count = g_list_length(forms);
  int *used_form_ids = calloc(form_count, sizeof(int));
 
  // check in history if the module has drawn masks and add it to used array
  int history_index = 0;
  for(GList *history_node = history_list; history_node && history_index < history_end;
      history_node = g_list_next(history_node))
  {
    dt_dev_history_item_t *history_item = (dt_dev_history_item_t *)history_node->data;
    dt_develop_blend_params_t *blend_params
        = history_item && history_item->blendop_params_size == sizeof(dt_develop_blend_params_t)
              ? history_item->blend_params
              : NULL;
    if(blend_params)
    {
      if(blend_params->mask_id > 0)
        _cleanup_unused_recurs(forms, blend_params->mask_id, used_form_ids, form_count);
    }
    history_index++;
  }
 
  // and we delete all unused forms
  GList *shape_node = forms;
  while(shape_node)
  {
    dt_masks_form_t *mask_form = (dt_masks_form_t *)shape_node->data;
    int is_used = 0;
    for(int used_index = 0; used_index < form_count; used_index++)
    {
      if(used_form_ids[used_index] == mask_form->formid)
      {
        is_used = 1;
        break;
      }
      if(used_form_ids[used_index] == 0) break;
    }
 
    shape_node = g_list_next(shape_node); // need to get 'next' now, because we may be removing the current node
 
    if(is_used == 0)
    {
      forms = g_list_remove(forms, mask_form);
      // and add it to allforms for cleanup
      darktable.develop->allforms = g_list_append(darktable.develop->allforms, mask_form);
      masks_removed = 1;
    }
  }
 
  dt_free(used_form_ids);
 
  *forms_list = forms;
 
  return masks_removed;
}
 
// removes all unused form from history
void dt_masks_cleanup_unused_from_list(GList *history_list)
{
  // a mask is used in a given hist->forms entry if it is used up to the next hist->forms
  // so we are going to remove for each hist->forms from the top
  int history_count = g_list_length(history_list);
  int history_end = history_count;
  for(const GList *history_node = g_list_last(history_list); history_node;
      history_node = g_list_previous(history_node))
  {
    dt_dev_history_item_t *history_item = (dt_dev_history_item_t *)history_node->data;
    if(!IS_NULL_PTR(history_item->forms)) //&& strcmp(history_item->op_name, "mask_manager") == 0)
    {
      _masks_cleanup_unused(&history_item->forms, history_list, history_end);
      history_end = history_count - 1;
    }
    history_count--;
  }
}
 
void dt_masks_cleanup_unused(dt_develop_t *develop)
{
  dt_masks_change_form_gui(NULL);
 
  // we remove the forms from history
  dt_masks_cleanup_unused_from_list(develop->history);
 
  // and we save all that
  GList *forms = NULL;
  int history_index = 0;
  for(const GList *history_node = g_list_first(develop->history);
      history_node && history_index < dt_dev_get_history_end_ext(develop);
      history_node = g_list_next(history_node))
  {
    dt_dev_history_item_t *history_item = (dt_dev_history_item_t *)history_node->data;
 
    if(history_item->forms) forms = history_item->forms;
    history_index++;
  }
 
  dt_masks_replace_current_forms(develop, forms);
}
 
int dt_masks_point_in_form_exact(const float *test_points, int test_point_count,
                                 const float *form_points, int form_points_start, int form_points_count)
{
  if(IS_NULL_PTR(test_points) || test_point_count <= 0 || IS_NULL_PTR(form_points)) return -1;
  if(form_points_count <= 2 + form_points_start) return -1;
  if(form_points_start < 0 || form_points_start >= form_points_count) return -1;
 
  const int start_index = form_points_start;
  for(int test_index = 0; test_index < test_point_count; test_index++)
  {
    int intersection_count = 0;
    const float point_x = test_points[test_index * 2];
    const float point_y = test_points[test_index * 2 + 1];
    int visited_points = 0;
 
    for(int i = form_points_start, next = start_index + 1; i < form_points_count;)
    {
      // The form point stream may contain NaN sentinels that jump across
      // self-intersection cuts. Broken jump targets must not trap the GUI event
      // loop in an endless hit-test.
      if(next < start_index || next >= form_points_count) break;
      if(++visited_points > form_points_count - start_index + 1) break;
 
      const float y1 = form_points[i * 2 + 1];
      const float y2 = form_points[next * 2 + 1];
 
      // if we need to skip points (in case of deleted point, because of self-intersection)
      if(isnan(form_points[next * 2]))
      {
        const int jump_index = isnan(y2) ? start_index : (int)y2;
        if(jump_index == next || jump_index < start_index || jump_index >= form_points_count) break;
        next = jump_index;
        continue;
      }
 
      if(((point_y <= y2 && point_y > y1) || (point_y >= y2 && point_y < y1))
         && (form_points[i * 2] > point_x))
        intersection_count++;
 
      if(next == start_index) break;
      i = next++;
      // loop
      if(next >= form_points_count) next = start_index;
    }
 
    if(intersection_count & 1) return test_index;
  }
 
  return -1;
}
 
void dt_masks_select_form(struct dt_iop_module_t *module, dt_masks_form_t *selected_form)
{
  const int selected_formid = IS_NULL_PTR(selected_form) ? 0 : selected_form->formid;
 
  if(IS_NULL_PTR(module) && selected_formid == 0)
    module = darktable.develop->gui_module;
 
  if(!IS_NULL_PTR(module) && module->masks_selection_changed)
    module->masks_selection_changed(module, selected_formid);
}
 
void dt_masks_set_source_pos_initial_state(dt_masks_form_gui_t *mask_gui, const uint32_t key_state)
{
  if(dt_modifier_is(key_state, GDK_SHIFT_MASK | GDK_CONTROL_MASK))
    mask_gui->source_pos_type = DT_MASKS_SOURCE_POS_ABSOLUTE;
  else if(dt_modifier_is(key_state, GDK_SHIFT_MASK))
    mask_gui->source_pos_type = DT_MASKS_SOURCE_POS_RELATIVE_TEMP;
  else
    fprintf(stderr, "[dt_masks_set_source_pos_initial_state] unknown state for setting masks position type\n");
 
  // both source types record an absolute position,
  // for the relative type, the first time is used the position is recorded,
  // the second time a relative position is calculated based on that one
  mask_gui->pos_source[0] = mask_gui->pos[0];
  mask_gui->pos_source[1] = mask_gui->pos[1];
}
 
void dt_masks_set_source_pos_initial_value(dt_masks_form_gui_t *mask_gui, dt_masks_form_t *mask_form)
{
  const float raw_width = darktable.develop->roi.raw_width;
  const float raw_height = darktable.develop->roi.raw_height;
 
  const float xx = mask_gui->pos[0];
  const float yy = mask_gui->pos[1];
 
  // if this is the first time the relative pos is used
  if(mask_gui->source_pos_type == DT_MASKS_SOURCE_POS_RELATIVE_TEMP)
  {
    // if it has not been defined by the user, set some default
    if(mask_gui->pos_source[0] == -1.0f && mask_gui->pos_source[1] == -1.0f)
    {
      if(mask_form->functions && mask_form->functions->initial_source_pos)
      {
        mask_form->functions->initial_source_pos(raw_width, raw_height,
                                                 &mask_gui->pos_source[0], &mask_gui->pos_source[1]);
      }
      else
        fprintf(stderr, "[dt_masks_set_source_pos_initial_value] unsupported masks type when calculating source position initial value\n");
 
      // set offset to form->source
      mask_form->source[0] = mask_gui->pos[0] + mask_gui->pos_source[0];
      mask_form->source[1] = mask_gui->pos[1] + mask_gui->pos_source[1];
      dt_dev_coordinates_image_abs_to_raw_abs(darktable.develop, mask_form->source, 1);
      // normalize backbuf points
      dt_dev_coordinates_raw_abs_to_raw_norm(darktable.develop, mask_form->source, 1);
 
    }
    else
    {
      // if a position was defined by the user, use the absolute value the first time
      float source_points[2] = { mask_gui->pos_source[0], mask_gui->pos_source[1] };
      dt_dev_coordinates_image_abs_to_raw_norm(darktable.develop, source_points, 1);
 
      mask_form->source[0] = source_points[0];
      mask_form->source[1] = source_points[1];
 
      mask_gui->pos_source[0] = mask_gui->pos_source[0] - xx;
      mask_gui->pos_source[1] = mask_gui->pos_source[1] - yy;
    }
 
    mask_gui->source_pos_type = DT_MASKS_SOURCE_POS_RELATIVE;
  }
  else if(mask_gui->source_pos_type == DT_MASKS_SOURCE_POS_RELATIVE)
  {
    // original pos was already defined and relative value calculated, just use it
    mask_form->source[0] = mask_gui->pos[0] + mask_gui->pos_source[0];
    mask_form->source[1] = mask_gui->pos[1] + mask_gui->pos_source[1];
    dt_dev_coordinates_image_abs_to_raw_norm(darktable.develop, mask_form->source, 1);
  }
  else if(mask_gui->source_pos_type == DT_MASKS_SOURCE_POS_ABSOLUTE)
  {
    // an absolute position was defined by the user
    float source_points[2] = { mask_gui->pos_source[0], mask_gui->pos_source[1] };
    dt_dev_coordinates_image_abs_to_raw_norm(darktable.develop, source_points, 1);
 
    mask_form->source[0] = source_points[0];
    mask_form->source[1] = source_points[1];
  }
  else
    fprintf(stderr, "[dt_masks_set_source_pos_initial_value] unknown source position type\n");
}
 
void dt_masks_calculate_source_pos_origin(dt_masks_form_gui_t *mask_gui, const float initial_xpos,
                                         const float initial_ypos, const float xpos, const float ypos,
                                         float *pos_x, float *pos_y, const int adding)
{
  float source_x = 0.0f;
  float source_y = 0.0f;
  const float raw_width = darktable.develop->roi.raw_width;
  const float raw_height = darktable.develop->roi.raw_height;
  if(mask_gui->source_pos_type == DT_MASKS_SOURCE_POS_RELATIVE)
  {
    source_x = xpos + mask_gui->pos_source[0];
    source_y = ypos + mask_gui->pos_source[1];
  }
  else if(mask_gui->source_pos_type == DT_MASKS_SOURCE_POS_RELATIVE_TEMP)
  {
    if(mask_gui->pos_source[0] == -1.0f && mask_gui->pos_source[1] == -1.0f)
    {
      const dt_masks_form_t *visible_form = dt_masks_get_visible_form(darktable.develop);
      if(!IS_NULL_PTR(visible_form) && visible_form->functions && visible_form->functions->initial_source_pos)
      {
        visible_form->functions->initial_source_pos(raw_width, raw_height, &source_x, &source_y);
        source_x += xpos;
        source_y += ypos;
      }
      else
        fprintf(stderr, "[dt_masks_calculate_source_pos_origin] unsupported masks type when calculating source position value\n");
    }
    else
    {
      source_x = mask_gui->pos_source[0];
      source_y = mask_gui->pos_source[1];
    }
  }
  else if(mask_gui->source_pos_type == DT_MASKS_SOURCE_POS_ABSOLUTE)
  {
    // if the user is actually adding, the mask follow the cursor
    if(adding)
    {
      source_x = xpos + mask_gui->pos_source[0] - initial_xpos;
      source_y = ypos + mask_gui->pos_source[1] - initial_ypos;
    }
    else
    {
      // if not added yet set the start position
      source_x = mask_gui->pos_source[0];
      source_y = mask_gui->pos_source[1];
    }
  }
  else
    fprintf(stderr, "[dt_masks_calculate_source_pos_origin] unknown source position type for setting source position value\n");
 
  *pos_x = source_x;
  *pos_y = source_y;
}
 
float dt_masks_rotate_with_anchor(dt_develop_t *develop, const float anchor[2], const float center[2],
                                  dt_masks_form_gui_t *mask_gui)
{
  const float center_x = center[0];
  const float center_y = center[1];
 
  // get the current angle
  const float anchor_x = anchor[0];
  const float anchor_y = anchor[1];
  const float angle_current = atan2f(anchor_y - center_y, anchor_x - center_x);
 
  // get the previous angle
  const float delta_x = mask_gui->delta[0];
  const float delta_y = mask_gui->delta[1];
  const float angle_prev = atan2f(delta_y - center_y, delta_x - center_x);
 
  // calculate the angle difference an normalize to -180 to 180 degrees
  float delta_angle = angle_current - angle_prev;
  float angle = atan2f(sinf(delta_angle), cosf(delta_angle));
 
  // check if distortion inverts the axes
  float test_points[8] = { center_x, center_y, anchor_x , anchor_y,
                           center_x + 10.0f, center_y, center_x, center_y + 10.0f };
  dt_dev_coordinates_image_abs_to_raw_abs(develop, test_points, 4);
  float check_angle = atan2f(test_points[7] - test_points[1], test_points[6] - test_points[0])
                      - atan2f(test_points[5] - test_points[1], test_points[4] - test_points[0]);
  // Normalize to the range -180 to 180 degrees
  check_angle = atan2f(sinf(check_angle), cosf(check_angle));
 
  // Adjust the sign if the axes are inverted by distortion
  if(check_angle < 0.0f) angle = -angle;
 
  // Update the delta for the next frame (old position becomes the current one)
  mask_gui->delta[0] = anchor_x;
  mask_gui->delta[1] = anchor_y;
 
  return angle / M_PI * 180.0f;
}
 
void dt_masks_creation_mode_quit(dt_masks_form_gui_t *mask_gui)
{
  if(IS_NULL_PTR(mask_gui)) return;
 
  mask_gui->creation = FALSE;
}
 
gboolean dt_masks_creation_mode_enter(dt_iop_module_t *module, const dt_masks_type_t type)
{
  if((type & DT_MASKS_ALL) == 0) return FALSE;
  // we want to be sure that the iop has focus
  if(!IS_NULL_PTR(module)) dt_iop_request_focus(module);
 
  dt_masks_form_t *mask_form = dt_masks_create(type);
  if(IS_NULL_PTR(mask_form)) return FALSE;
 
  dt_masks_change_form_gui(mask_form);
  darktable.develop->form_gui->creation = TRUE;
  darktable.develop->form_gui->creation_module = module;
  darktable.develop->form_gui->creation_type = type;
  darktable.develop->form_gui->creation_formids = NULL;
  darktable.develop->form_gui->creation_last_formid = 0;
 
  // Give focus to central view to allow using shortcuts for mask creation right after selecting a mask type in the manager
  gtk_widget_grab_focus(dt_ui_center(darktable.gui->ui));
  return TRUE;
}
 
void apply_operation(struct dt_masks_form_group_t *group_entry, const dt_masks_state_t apply_state)
{
  if(IS_NULL_PTR(group_entry)) return;
 
  // Apply Inverse
  if(apply_state == DT_MASKS_STATE_INVERSE)
    group_entry->state ^= DT_MASKS_STATE_INVERSE;
  
  else if((apply_state & DT_MASKS_STATE_IS_COMBINE_OP) != 0)
  {
    // Reset all and apply state
    group_entry->state = (group_entry->state & ~DT_MASKS_STATE_IS_COMBINE_OP) | apply_state;
  }
}
 
#include "detail.c"
 
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