Bug 735891 - color areas in the color picker info window are half transparent

Add code to GimpOverlayChild which can render arbitrary children of
the widget fully opaque, ignoring the configured opacity.

Add gimp_widget_get,set_fully_opaque() which gets/sets a per-widget
boolean flag to trigger that code.

Set the color picker's and the text tool style widget's color areas to
fully opaque.

app/tools/gimpcolorpickertool.c

@@ -371,6 +371,7 @@ gimp_color_picker_tool_info_create (GimpColorPickerTool *picker_tool)
   gtk_widget_show (picker_tool->color_frame2);
 
   frame = gtk_frame_new (NULL);
+  gimp_widget_set_fully_opaque (frame, TRUE);
   gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_IN);
   gtk_box_pack_start (GTK_BOX (hbox), frame, TRUE, TRUE, 0);
   gtk_widget_show (frame);

app/widgets/gimpoverlaychild.c

@@ -31,6 +31,7 @@
 
 #include "gimpoverlaybox.h"
 #include "gimpoverlaychild.h"
+#include "gimpwidgets-utils.h"
 
 
 /*  local function prototypes  */
@@ -302,6 +303,42 @@ gimp_overlay_child_size_allocate (GimpOverlayBox   *box,
   gimp_overlay_child_invalidate (box, child);
 }
 
+static void
+gimp_overlay_child_clip_fully_opaque (GimpOverlayChild *child,
+                                      GtkContainer     *container,
+                                      cairo_t          *cr)
+{
+  GList *children;
+  GList *list;
+
+  children = gtk_container_get_children (container);
+
+  for (list = children; list; list = g_list_next (list))
+    {
+      GtkWidget *widget = list->data;
+
+      if (gimp_widget_get_fully_opaque (widget))
+        {
+          GtkAllocation allocation;
+          gint          x, y;
+
+          gtk_widget_get_allocation (widget, &allocation);
+          gtk_widget_translate_coordinates (widget, child->widget,
+                                            0, 0, &x, &y);
+
+          cairo_rectangle (cr, x, y, allocation.width, allocation.height);
+        }
+      else if (GTK_IS_CONTAINER (widget))
+        {
+          gimp_overlay_child_clip_fully_opaque (child,
+                                                GTK_CONTAINER (widget),
+                                                cr);
+        }
+    }
+
+  g_list_free (children);
+}
+
 gboolean
 gimp_overlay_child_expose (GimpOverlayBox   *box,
                            GimpOverlayChild *child,
@@ -341,6 +378,13 @@ gimp_overlay_child_expose (GimpOverlayBox   *box,
           cairo_transform (cr, &child->matrix);
           gdk_cairo_set_source_pixmap (cr, pixmap, 0, 0);
           cairo_paint_with_alpha (cr, child->opacity);
+
+          gimp_overlay_child_clip_fully_opaque (child,
+                                                GTK_CONTAINER (child->widget),
+                                                cr);
+          cairo_clip (cr);
+          cairo_paint (cr);
+
           cairo_destroy (cr);
         }
     }

app/widgets/gimptextstyleeditor.c

@@ -41,6 +41,7 @@
 #include "gimptextbuffer.h"
 #include "gimptextstyleeditor.h"
 #include "gimptexttag.h"
+#include "gimpwidgets-utils.h"
 
 #include "gimp-intl.h"
 
@@ -247,6 +248,7 @@ gimp_text_style_editor_init (GimpTextStyleEditor *editor)
   editor->color_button = gimp_color_panel_new (_("Change color of selected text"),
                                                &color,
                                                GIMP_COLOR_AREA_FLAT, 20, 20);
+  gimp_widget_set_fully_opaque (editor->color_button, TRUE);
 
   gtk_box_pack_end (GTK_BOX (editor->lower_hbox), editor->color_button,
                     FALSE, FALSE, 0);

app/widgets/gimpwidgets-utils.c

@@ -1264,6 +1264,26 @@ gimp_widget_flush_expose (GtkWidget *widget)
   gdk_flush ();
 }
 
+gboolean
+gimp_widget_get_fully_opaque (GtkWidget *widget)
+{
+  g_return_val_if_fail (GTK_IS_WIDGET (widget), FALSE);
+
+  return g_object_get_data (G_OBJECT (widget),
+                            "gimp-widget-fully-opaque") != NULL;
+}
+
+void
+gimp_widget_set_fully_opaque (GtkWidget *widget,
+                              gboolean   fully_opaque)
+{
+  g_return_if_fail (GTK_IS_WIDGET (widget));
+
+  return g_object_set_data (G_OBJECT (widget),
+                            "gimp-widget-fully-opaque",
+                            GINT_TO_POINTER (fully_opaque));
+}
+
 static gboolean
 gimp_print_event_free (gpointer data)
 {

app/widgets/gimpwidgets-utils.h

@@ -97,12 +97,16 @@ GtkWidget       * gimp_dock_with_window_new        (GimpDialogFactory    *factor
                                                     GdkScreen            *screen,
                                                     gint                  monitor,
                                                     gboolean              toolbox);
-GtkWidget *       gimp_tools_get_tool_options_gui  (GimpToolOptions      *tool_options);
+GtkWidget       * gimp_tools_get_tool_options_gui  (GimpToolOptions      *tool_options);
 void              gimp_tools_set_tool_options_gui  (GimpToolOptions      *tool_options,
                                                     GtkWidget            *widget);
 
 void              gimp_widget_flush_expose         (GtkWidget            *widget);
 
+gboolean          gimp_widget_get_fully_opaque     (GtkWidget            *widget);
+void              gimp_widget_set_fully_opaque     (GtkWidget            *widget,
+                                                    gboolean              fully_opaque);
+
 const gchar     * gimp_print_event                 (const GdkEvent       *event);
 
 void              gimp_session_write_position      (GimpConfigWriter     *writer,