widget_style.c

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/*
 *    This file is part of darktable,
 *    Copyright (C) 2016 johannes hanika.
 *    Copyright (C) 2016, 2020 Tobias Ellinghaus.
 *    Copyright (C) 2020 Pascal Obry.
 *    Copyright (C) 2021 Sakari Kapanen.
 *    Copyright (C) 2022 Martin Bařinka.
 *    
 *    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 "widgets/widget_style.h"
#include "widgets/widget_settings.h"
#include "system/macros.h"   // IS_NULL_PTR -- a pure macro header, no state
 
#include <pango/pangocairo.h>
 
#include <glib.h>
#include <string.h>
 
void dt_gui_add_class(GtkWidget *widget, const gchar *class_name)
{
  GtkStyleContext *context = gtk_widget_get_style_context(widget);
  if(!gtk_style_context_has_class(context, class_name))
  {
    gtk_style_context_add_class(context, class_name);
    gtk_widget_queue_draw(widget);
  }
}
 
void dt_gui_remove_class(GtkWidget *widget, const gchar *class_name)
{
  GtkStyleContext *context = gtk_widget_get_style_context(widget);
  if(gtk_style_context_has_class(context, class_name))
  {
    gtk_style_context_remove_class(context, class_name);
    gtk_widget_queue_draw(widget);
  }
}
 
void dt_capitalize_label(gchar *text)
{
  if(!text || !text[0]) return;
 
  // Deal with strings beginning with a Mnemonics underscore
  gchar *p = text;
  if(*p == '_' && p[1]) p++;
 
  // `p[0] = g_unichar_toupper(p[0])` used to write here directly, but `p[0]` is only
  // the first *byte* of `p`, not the first character: translated labels routinely
  // start with a multi-byte UTF-8 character (accented capitals, non-Latin scripts).
  // Mutating one byte of a multi-byte sequence produces a different, still
  // "valid-looking" sequence followed by an orphaned continuation byte - invalid
  // UTF-8 that crashes later collation (e.g. g_utf8_collate -> glibc wcscoll_l).
  gunichar c = g_utf8_get_char_validated(p, -1);
  if(c == (gunichar)-1 || c == (gunichar)-2) return; // invalid UTF-8, leave untouched
 
  gunichar upper = g_unichar_toupper(c);
  if(upper == c) return;
 
  gchar utf8_buf[6] = { 0 };
  gint n = g_unichar_to_utf8(upper, utf8_buf);
  gint orig_len = g_utf8_next_char(p) - p;
 
  // Callers pass buffers sized exactly for the original string (often g_strdup'd),
  // not a longer one - only mutate in place if the uppercase form fits.
  if(n == orig_len) memcpy(p, utf8_buf, n);
}
 
void dt_gui_cairo_set_font_options(cairo_t *cr, GtkWidget *widget)
{
  if(IS_NULL_PTR(cr)) return;
 
  // Source GTK's resolved text-rendering options (anti-aliasing, hinting, subpixel order,
  // hint-metrics/kerning), which GTK populates from GtkSettings/Xft/fontconfig. The widget's
  // Pango context is the same source native widgets use; fall back to the main window, then to the
  // screen defaults, so an off-screen/scratch Cairo surface never silently reverts to Cairo's
  // AA-on defaults (which would make our cairo-drawn text look unlike the rest of the UI).
  const cairo_font_options_t *fo = NULL;
 
  if(widget)
  {
    PangoContext *pc = gtk_widget_get_pango_context(widget);
    if(pc) fo = pango_cairo_context_get_font_options(pc);
  }
  if(!fo)
  {
    GtkWidget *root = dt_widget_root_window();
    if(root)
    {
      PangoContext *pc = gtk_widget_get_pango_context(root);
      if(pc) fo = pango_cairo_context_get_font_options(pc);
    }
  }
  if(!fo)
  {
    GdkScreen *screen = gdk_screen_get_default();
    if(screen) fo = gdk_screen_get_font_options(screen);
  }
 
  // cairo_set_font_options() copies internally, so the const pointer's lifetime is not a concern.
  if(fo) cairo_set_font_options(cr, fo);
}
 
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