[gimp] Bug 770424 - Themes: insensitive menu item are not readable.

[Jehan Pagès <jehanp src gnome org>]

commit 18a96d92682fbeddfa48883d17f46c50cf15d7eb
Author: Jehan <jehan girinstud io>
Date:   Fri Dec 1 03:05:14 2017 +0100

    Bug 770424 - Themes: insensitive menu item are not readable.
    
    Not sure if g_type_class_ref() can actually return NULL here, but let's
    add a check, just in case.
    Also unref() after since we ref-ed it ourselves.
    Finally reorganize a bit to keep the private functions together and
    named appropriately, clean some tabs and add a comment to remind of
    further check/cleanup once we port to GTK+3.

 app/gui/themes.c |  135 +++++++++++++++++++++++++++++++----------------------
 1 files changed, 79 insertions(+), 56 deletions(-)
---
diff --git a/app/gui/themes.c b/app/gui/themes.c
index 6be00dc..0cf68bc 100644
--- a/app/gui/themes.c
+++ b/app/gui/themes.c
@@ -52,67 +52,22 @@ static void   themes_theme_change_notify (GimpGuiConfig          *config,
                                           GParamSpec             *pspec,
                                           Gimp                   *gimp);
 
+static void   themes_draw_layout         (GtkStyle               *style,
+                                          GdkWindow              *window,
+                                          GtkStateType            state_type,
+                                          gboolean                use_text,
+                                          GdkRectangle           *area,
+                                          GtkWidget              *widget,
+                                          const gchar            *detail,
+                                          gint                    x,
+                                          gint                    y,
+                                          PangoLayout            *layout);
 
 /*  private variables  */
 
 static GHashTable *themes_hash = NULL;
 
 
-static void
-draw_layout (GtkStyle        *style,
-            GdkWindow       *window,
-            GtkStateType     state_type,
-            gboolean         use_text,
-            GdkRectangle    *area,
-            GtkWidget       *widget,
-            const gchar     *detail,
-            gint             x,
-            gint             y,
-            PangoLayout     *layout)
-{
-  GdkGC *gc;
-
-  gc = use_text ? style->text_gc[state_type] : style->fg_gc[state_type];
-
-  if (area)
-    gdk_gc_set_clip_rectangle (gc, area);
-
-  if (state_type == GTK_STATE_INSENSITIVE)
-    {
-      GdkGCValues orig;
-      GdkColor fore;
-      GdkGC *copy = gdk_gc_new (window);
-      guint16 r, g, b;
-
-      gdk_gc_copy (copy, gc);
-
-      gdk_gc_get_values (gc, &orig);
-
-      r = 0x40 + (((orig.foreground.pixel >> 16) & 0xff) >> 1);
-      g = 0x40 + (((orig.foreground.pixel >>  8) & 0xff) >> 1);
-      b = 0x40 + (((orig.foreground.pixel >>  0) & 0xff) >> 1);
-
-      fore.pixel = (r << 16) | (g << 8) | b;
-      fore.red   = r * 257;
-      fore.green = g * 257;
-      fore.blue  = b * 257;
-
-      gdk_gc_set_foreground (copy, &fore);
-
-      gdk_draw_layout (window, copy, x, y, layout);
-
-      g_object_unref (copy);
-    }
-  else
-    {
-      gdk_draw_layout (window, gc, x, y, layout);
-    }
-
-  if (area)
-    gdk_gc_set_clip_rectangle (gc, NULL);
-}
-
-
 /*  public functions  */
 
 void
@@ -120,10 +75,24 @@ themes_init (Gimp *gimp)
 {
   GimpGuiConfig *config;
   gchar         *themerc;
+  gpointer       pixbuf_style_type_class;
 
   g_return_if_fail (GIMP_IS_GIMP (gimp));
 
-  GTK_STYLE_CLASS (g_type_class_ref (g_type_from_name ("PixbufStyle")))->draw_layout = draw_layout;
+  /* This is a "quick'n dirty" trick to get appropriate colors for
+   * themes in GTK+2, and in particular dark themes which would display
+   * insensitive items with a barely readable layout.
+   * This piece of code partly duplicates code from GTK+2 (slightly
+   * modified to get readable insensitive items) and will likely have to
+   * be removed for GIMP 3.
+   * See https://bugzilla.gnome.org/show_bug.cgi?id=770424
+   */
+  pixbuf_style_type_class = g_type_class_ref (g_type_from_name ("PixbufStyle"));
+  if (pixbuf_style_type_class)
+    {
+      GTK_STYLE_CLASS (pixbuf_style_type_class)->draw_layout = themes_draw_layout;
+      g_type_class_unref (pixbuf_style_type_class);
+    }
 
   config = GIMP_GUI_CONFIG (gimp->config);
 
@@ -425,3 +394,57 @@ themes_theme_change_notify (GimpGuiConfig *config,
 
   gtk_rc_reparse_all ();
 }
+
+static void
+themes_draw_layout (GtkStyle      *style,
+                    GdkWindow     *window,
+                    GtkStateType   state_type,
+                    gboolean       use_text,
+                    GdkRectangle  *area,
+                    GtkWidget     *widget,
+                    const gchar   *detail,
+                    gint           x,
+                    gint           y,
+                    PangoLayout   *layout)
+{
+  GdkGC *gc;
+
+  gc = use_text ? style->text_gc[state_type] : style->fg_gc[state_type];
+
+  if (area)
+    gdk_gc_set_clip_rectangle (gc, area);
+
+  if (state_type == GTK_STATE_INSENSITIVE)
+    {
+      GdkGCValues orig;
+      GdkColor fore;
+      GdkGC *copy = gdk_gc_new (window);
+      guint16 r, g, b;
+
+      gdk_gc_copy (copy, gc);
+
+      gdk_gc_get_values (gc, &orig);
+
+      r = 0x40 + (((orig.foreground.pixel >> 16) & 0xff) >> 1);
+      g = 0x40 + (((orig.foreground.pixel >>  8) & 0xff) >> 1);
+      b = 0x40 + (((orig.foreground.pixel >>  0) & 0xff) >> 1);
+
+      fore.pixel = (r << 16) | (g << 8) | b;
+      fore.red   = r * 257;
+      fore.green = g * 257;
+      fore.blue  = b * 257;
+
+      gdk_gc_set_foreground (copy, &fore);
+
+      gdk_draw_layout (window, copy, x, y, layout);
+
+      g_object_unref (copy);
+    }
+  else
+    {
+      gdk_draw_layout (window, gc, x, y, layout);
+    }
+
+  if (area)
+    gdk_gc_set_clip_rectangle (gc, NULL);
+}