thumbnail_btn.c

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/*
    This file is part of darktable,
    Copyright (C) 2020, 2022 Aldric Renaudin.
    Copyright (C) 2021 Dan Torop.
    Copyright (C) 2021 Heiko Bauke.
    Copyright (C) 2021 Hubert Kowalski.
    Copyright (C) 2022, 2025 Aurélien PIERRE.
    Copyright (C) 2022 Diederik Ter Rahe.
    Copyright (C) 2022 Martin Bařinka.
    Copyright (C) 2022 Nicolas Auffray.
    
    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 "thumbnail_btn.h"
#include "system/macros.h"   // IS_NULL_PTR -- a pure macro header, no state
#include "widgets/widget_style.h"
#include <string.h>
 
static void _thumbnail_btn_class_init(GtkDarktableThumbnailBtnClass *klass);
static void _thumbnail_btn_init(GtkDarktableThumbnailBtn *button);
static gboolean _thumbnail_btn_draw(GtkWidget *widget, cairo_t *cr);
static gboolean _thumbnail_btn_enter_leave_notify_callback(GtkWidget *widget, GdkEventCrossing *event);
 
static void _thumbnail_btn_class_init(GtkDarktableThumbnailBtnClass *klass)
{
  GtkWidgetClass *widget_class = (GtkWidgetClass *)klass;
 
  widget_class->draw = _thumbnail_btn_draw;
  widget_class->enter_notify_event = _thumbnail_btn_enter_leave_notify_callback;
  widget_class->leave_notify_event = _thumbnail_btn_enter_leave_notify_callback;
}
 
static void _thumbnail_btn_init(GtkDarktableThumbnailBtn *button)
{
}
 
static gboolean _thumbnail_btn_draw(GtkWidget *widget, cairo_t *cr)
{
  g_return_val_if_fail(DTGTK_IS_THUMBNAIL_BTN(widget), FALSE);
 
  if(gtk_widget_get_allocated_height(widget) < 2 || gtk_widget_get_allocated_width(widget) < 2) return TRUE;
 
  GtkStateFlags state = gtk_widget_get_state_flags(widget);
 
  GdkRGBA *fg_color, *bg_color;
  GtkStyleContext *context = gtk_widget_get_style_context(widget);
  gtk_style_context_get(context, state, GTK_STYLE_PROPERTY_COLOR, &fg_color, GTK_STYLE_PROPERTY_BACKGROUND_COLOR,
                        &bg_color, NULL);
 
  GtkBorder margin;
  gtk_style_context_get_margin(context, state, &margin);
  gtk_widget_set_margin_bottom(widget, margin.bottom);
  gtk_widget_set_margin_top(widget, margin.top);
  gtk_widget_set_margin_start(widget, margin.left);
  gtk_widget_set_margin_end(widget, margin.right);
 
  if(fg_color->alpha == 0 && bg_color->alpha == 0)
  {
    DTGTK_THUMBNAIL_BTN(widget)->hidden = TRUE;
    gdk_rgba_free(fg_color);
    gdk_rgba_free(bg_color);
    return TRUE;
  }
  DTGTK_THUMBNAIL_BTN(widget)->hidden = FALSE;
 
  cairo_save(cr);
  gdk_cairo_set_source_rgba(cr, fg_color);
 
  /* draw icon */
  if(DTGTK_THUMBNAIL_BTN(widget)->icon)
  {
    GtkAllocation allocation;
    gtk_widget_get_allocation(widget, &allocation);
 
    int flags = DTGTK_THUMBNAIL_BTN(widget)->icon_flags;
    if(state & GTK_STATE_FLAG_PRELIGHT)
      flags |= CPF_PRELIGHT;
    else
      flags &= ~CPF_PRELIGHT;
 
    if(state & GTK_STATE_FLAG_ACTIVE)
      flags |= CPF_ACTIVE;
    else
      flags &= ~CPF_ACTIVE;
 
    GtkBorder padding;
    gtk_style_context_get_padding(context, state, &padding);
    // padding is a percent of the full size
    const float icon_x = padding.left;
    const float icon_y = padding.top;
    const float icon_w = allocation.width - (padding.left + padding.right);
    const float icon_h = allocation.height - (padding.top + padding.bottom);
    // Only paint when there is positive room for the icon. The paint helpers do
    // cairo_scale(cr, w, h); a zero dimension makes that matrix non-invertible, which poisons the
    // shared cairo context and cascades a "drawing failure ... invalid matrix" up the whole widget
    // tree. Padding can eat the whole allocation on tiny buttons (e.g. filmstrip thumbnails during
    // a view transition), so the >= 2px allocation guard above is not enough on its own.
    if(icon_w > 0.f && icon_h > 0.f)
      DTGTK_THUMBNAIL_BTN(widget)->icon(
          cr, icon_x, icon_y, icon_w, icon_h, flags,
          DTGTK_THUMBNAIL_BTN(widget)->icon_data ? DTGTK_THUMBNAIL_BTN(widget)->icon_data : bg_color);
  }
  // and eventually the image border
  cairo_restore(cr);
  gtk_render_frame(context, cr, 0, 0, gtk_widget_get_allocated_width(widget),
                   gtk_widget_get_allocated_height(widget));
 
  gdk_rgba_free(fg_color);
  gdk_rgba_free(bg_color);
  return TRUE;
}
 
static gboolean _thumbnail_btn_enter_leave_notify_callback(GtkWidget *widget, GdkEventCrossing *event)
{
  g_return_val_if_fail(!IS_NULL_PTR(widget), FALSE);
 
  if(event->type == GDK_ENTER_NOTIFY)
    gtk_widget_set_state_flags(widget, GTK_STATE_FLAG_PRELIGHT, FALSE);
  else
    gtk_widget_unset_state_flags(widget, GTK_STATE_FLAG_PRELIGHT);
 
  gtk_widget_queue_draw(widget);
  return FALSE;
}
 
// Public functions
GtkWidget *dtgtk_thumbnail_btn_new(DTGTKCairoPaintIconFunc paint, gint paintflags, void *paintdata)
{
  GtkDarktableThumbnailBtn *button;
  button = g_object_new(dtgtk_thumbnail_btn_get_type(), NULL);
  dt_gui_add_class(GTK_WIDGET(button), "dt_thumb_btn");
  button->icon = paint;
  button->icon_flags = paintflags;
  button->icon_data = paintdata;
  gtk_widget_set_events(GTK_WIDGET(button), GDK_BUTTON_PRESS_MASK | GDK_BUTTON_RELEASE_MASK | GDK_ENTER_NOTIFY_MASK
                                                | GDK_LEAVE_NOTIFY_MASK);
  gtk_widget_set_app_paintable(GTK_WIDGET(button), TRUE);
  gtk_widget_set_name(GTK_WIDGET(button), "thumbnail_btn");
  return (GtkWidget *)button;
}
 
GType dtgtk_thumbnail_btn_get_type()
{
  static GType dtgtk_thumbnail_btn_type = 0;
  if(!dtgtk_thumbnail_btn_type)
  {
    static const GTypeInfo dtgtk_thumbnail_btn_info = {
      sizeof(GtkDarktableThumbnailBtnClass),
      (GBaseInitFunc)NULL,
      (GBaseFinalizeFunc)NULL,
      (GClassInitFunc)_thumbnail_btn_class_init,
      NULL, /* class_finalize */
      NULL, /* class_data */
      sizeof(GtkDarktableThumbnailBtn),
      0, /* n_preallocs */
      (GInstanceInitFunc)_thumbnail_btn_init,
    };
    dtgtk_thumbnail_btn_type
        = g_type_register_static(GTK_TYPE_DRAWING_AREA, "GtkDarktableThumbnailBtn", &dtgtk_thumbnail_btn_info, 0);
  }
  return dtgtk_thumbnail_btn_type;
}
 
gboolean dtgtk_thumbnail_btn_is_hidden(GtkWidget *widget)
{
  g_return_val_if_fail(DTGTK_IS_THUMBNAIL_BTN(widget), TRUE);
 
  return DTGTK_THUMBNAIL_BTN(widget)->hidden;
}
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