[gthumb] desktop background: allow to set an xcf image as background image

[Paolo Bacchilega <paobac src gnome org>]

commit 0a18437462c8bc64a686228d34d309a6861eec22
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Thu Mar 14 11:59:57 2013 +0100

    desktop background: allow to set an xcf image as background image
    
    convert the image to jpeg if the mime type is not supported by GdkPixbuf

 extensions/desktop_background/actions.c |   18 ++++++++-------
 gthumb/pixbuf-utils.c                   |   35 +++++++++++++++++++++++++++++++
 gthumb/pixbuf-utils.h                   |    1 +
 3 files changed, 46 insertions(+), 8 deletions(-)
---
diff --git a/extensions/desktop_background/actions.c b/extensions/desktop_background/actions.c
index 6dbf7e3..5c90844 100644
--- a/extensions/desktop_background/actions.c
+++ b/extensions/desktop_background/actions.c
@@ -255,13 +255,21 @@ gth_browser_activate_action_tool_desktop_background (GtkAction  *action,
 {
        WallpaperData *wdata;
        gboolean       saving_wallpaper = FALSE;
-       GthFileData   *file_data;
        GList         *items;
        GList         *file_list;
+       GthFileData   *file_data;
+       const char    *mime_type;
 
        wdata = wallpaper_data_new (browser);
 
-       if (gth_main_extension_is_active ("image_viewer") && gth_browser_get_file_modified (browser)) {
+       items = gth_file_selection_get_selected (GTH_FILE_SELECTION (gth_browser_get_file_list_view 
(browser)));
+       file_list = gth_file_list_get_files (GTH_FILE_LIST (gth_browser_get_file_list (browser)), items);
+       file_data = (file_list != NULL) ? file_list->data : NULL;
+       mime_type = (file_data != NULL) ? gth_file_data_get_mime_type (file_data) : NULL;
+
+       if (gth_main_extension_is_active ("image_viewer")
+           && (gth_browser_get_file_modified (browser) || ! _gdk_pixbuf_mime_type_is_readable (mime_type)))
+       {
                GtkWidget *viewer_page;
 
                viewer_page = gth_browser_get_viewer_page (browser);
@@ -291,12 +299,6 @@ gth_browser_activate_action_tool_desktop_background (GtkAction  *action,
        if (saving_wallpaper)
                return;
 
-       items = gth_file_selection_get_selected (GTH_FILE_SELECTION (gth_browser_get_file_list_view 
(browser)));
-       file_list = gth_file_list_get_files (GTH_FILE_LIST (gth_browser_get_file_list (browser)), items);
-       if (file_list == NULL)
-               return;
-
-       file_data = file_list->data;
        if (file_data == NULL)
                return;
 
diff --git a/gthumb/pixbuf-utils.c b/gthumb/pixbuf-utils.c
index faadda0..311c567 100644
--- a/gthumb/pixbuf-utils.c
+++ b/gthumb/pixbuf-utils.c
@@ -196,3 +196,38 @@ _gdk_pixbuf_get_type_from_mime_type (const char *mime_type)
        else
                return g_strdup (mime_type);
 }
+
+
+gboolean
+_gdk_pixbuf_mime_type_is_readable (const char *mime_type)
+{
+       GSList   *formats;
+       GSList   *scan;
+       gboolean  result;
+
+       if (mime_type == NULL)
+               return FALSE;
+
+       result = FALSE;
+       formats = gdk_pixbuf_get_formats ();
+       for (scan = formats; ! result && scan; scan = scan->next) {
+               GdkPixbufFormat  *format = scan->data;
+               char            **mime_types;
+               int               i;
+
+               if (gdk_pixbuf_format_is_disabled (format))
+                       continue;
+
+               mime_types = gdk_pixbuf_format_get_mime_types (format);
+               for (i = 0; mime_types[i] != NULL; i++) {
+                       if (strcmp (mime_type, mime_types[i]) == 0) {
+                               result = TRUE;
+                               break;
+                       }
+               }
+       }
+
+       g_slist_free (formats);
+
+       return result;
+}
diff --git a/gthumb/pixbuf-utils.h b/gthumb/pixbuf-utils.h
index b51d76e..5f4a373 100644
--- a/gthumb/pixbuf-utils.h
+++ b/gthumb/pixbuf-utils.h
@@ -39,6 +39,7 @@ GdkPixbuf * _gdk_pixbuf_scale_simple_safe        (const GdkPixbuf *src,
 GdkPixbuf * _gdk_pixbuf_transform                (GdkPixbuf       *src,
                                                  GthTransform     transform);
 char *      _gdk_pixbuf_get_type_from_mime_type  (const char      *mime_type);
+gboolean    _gdk_pixbuf_mime_type_is_readable    (const char      *mime_type);
 
 G_END_DECLS