[gnome-software/wip/hughsie/use_desktop_background] Do not composite screenshots with internal alpha sections

[Richard Hughes <rhughes src gnome org>]

commit a31973c79f2ee6624fab4479a49a8cc96b31002e
Author: Richard Hughes <richard hughsie com>
Date:   Fri May 17 13:57:41 2019 +0100

    Do not composite screenshots with internal alpha sections
    
    Fixes https://gitlab.gnome.org/GNOME/gnome-software/issues/90

 src/gs-details-page.c     |  1 -
 src/gs-screenshot-image.c | 83 +++--------------------------------------------
 src/gs-screenshot-image.h |  3 --
 3 files changed, 5 insertions(+), 82 deletions(-)
---
diff --git a/src/gs-details-page.c b/src/gs-details-page.c
index 9e1b7274..b074af4d 100644
--- a/src/gs-details-page.c
+++ b/src/gs-details-page.c
@@ -515,7 +515,6 @@ gs_details_page_refresh_screenshots (GsDetailsPage *self)
                        gs_screenshot_image_set_size (GS_SCREENSHOT_IMAGE (ssimg),
                                                      640,
                                                      48);
-                       gs_screenshot_image_set_use_desktop_background (GS_SCREENSHOT_IMAGE (ssimg), FALSE);
                        gs_screenshot_image_load_async (GS_SCREENSHOT_IMAGE (ssimg), NULL);
                        gtk_container_add (GTK_CONTAINER (self->box_details_screenshot_main), ssimg);
                        gtk_widget_set_visible (ssimg, TRUE);
diff --git a/src/gs-screenshot-image.c b/src/gs-screenshot-image.c
index f7bee329..cd68f7c2 100644
--- a/src/gs-screenshot-image.c
+++ b/src/gs-screenshot-image.c
@@ -11,12 +11,6 @@
 
 #include <glib/gi18n.h>
 
-#ifdef HAVE_GNOME_DESKTOP
-#define GNOME_DESKTOP_USE_UNSTABLE_API
-#include <libgnome-desktop/gnome-bg.h>
-#include <libgnome-desktop/gnome-desktop-thumbnail.h>
-#endif
-
 #include "gs-screenshot-image.h"
 #include "gs-common.h"
 
@@ -35,7 +29,6 @@ struct _GsScreenshotImage
        SoupMessage     *message;
        gchar           *filename;
        const gchar     *current_image;
-       gboolean         use_desktop_background;
        guint            width;
        guint            height;
        guint            scale;
@@ -66,91 +59,34 @@ gs_screenshot_image_set_error (GsScreenshotImage *ssimg, const gchar *message)
        ssimg->showing_image = FALSE;
 }
 
-static GdkPixbuf *
-gs_screenshot_image_get_desktop_pixbuf (GsScreenshotImage *ssimg)
-{
-#ifdef HAVE_GNOME_DESKTOP
-       g_autoptr(GnomeBG) bg = NULL;
-       g_autoptr(GnomeDesktopThumbnailFactory) factory = NULL;
-       g_autoptr(GSettings) settings = NULL;
-
-       factory = gnome_desktop_thumbnail_factory_new (GNOME_DESKTOP_THUMBNAIL_SIZE_LARGE);
-       bg = gnome_bg_new ();
-       settings = g_settings_new ("org.gnome.desktop.background");
-       gnome_bg_load_from_preferences (bg, settings);
-       return gnome_bg_create_thumbnail (bg, factory,
-                                         gdk_screen_get_default (),
-                                         (gint) ssimg->width,
-                                         (gint) ssimg->height);
-#else
-       return NULL;
-#endif
-}
-
-static gboolean
-gs_screenshot_image_use_desktop_background (GsScreenshotImage *ssimg, GdkPixbuf *pixbuf)
-{
-       g_autoptr(AsImage) im = NULL;
-
-       /* nothing to show, means no background mode */
-       if (pixbuf == NULL)
-               return FALSE;
-       /* background mode explicitly disabled */
-       if (!ssimg->use_desktop_background)
-               return FALSE;
-
-       /* use a temp AsImage */
-       im = as_image_new ();
-       as_image_set_pixbuf (im, pixbuf);
-       return (as_image_get_alpha_flags (im) & AS_IMAGE_ALPHA_FLAG_INTERNAL) > 0;
-}
-
 static void
 as_screenshot_show_image (GsScreenshotImage *ssimg)
 {
-       g_autoptr(GdkPixbuf) pixbuf_bg = NULL;
        g_autoptr(GdkPixbuf) pixbuf = NULL;
 
        /* no need to composite */
        if (ssimg->width == G_MAXUINT || ssimg->height == G_MAXUINT) {
-               pixbuf_bg = gdk_pixbuf_new_from_file (ssimg->filename, NULL);
+               pixbuf = gdk_pixbuf_new_from_file (ssimg->filename, NULL);
        } else {
                /* this is always going to have alpha */
                pixbuf = gdk_pixbuf_new_from_file_at_scale (ssimg->filename,
                                                            (gint) (ssimg->width * ssimg->scale),
                                                            (gint) (ssimg->height * ssimg->scale),
                                                            FALSE, NULL);
-               if (pixbuf != NULL) {
-                       if (gs_screenshot_image_use_desktop_background (ssimg, pixbuf)) {
-                               pixbuf_bg = gs_screenshot_image_get_desktop_pixbuf (ssimg);
-                               if (pixbuf_bg == NULL) {
-                                       pixbuf_bg = g_object_ref (pixbuf);
-                               } else {
-                                       gdk_pixbuf_composite (pixbuf, pixbuf_bg,
-                                                             0, 0,
-                                                             (gint) ssimg->width,
-                                                             (gint) ssimg->height,
-                                                             0, 0, 1.0f, 1.0f,
-                                                             GDK_INTERP_NEAREST, 255);
-                               }
-                       } else {
-                               pixbuf_bg = g_object_ref (pixbuf);
-                       }
-               }
        }
 
        /* show icon */
        if (g_strcmp0 (ssimg->current_image, "image1") == 0) {
-               if (pixbuf_bg != NULL) {
+               if (pixbuf != NULL) {
                        gs_image_set_from_pixbuf_with_scale (GTK_IMAGE (ssimg->image2),
-                                                            pixbuf_bg, (gint) ssimg->scale);
+                                                            pixbuf, (gint) ssimg->scale);
                }
                gtk_stack_set_visible_child_name (GTK_STACK (ssimg->stack), "image2");
                ssimg->current_image = "image2";
        } else {
-               if (pixbuf_bg != NULL) {
+               if (pixbuf != NULL) {
                        gs_image_set_from_pixbuf_with_scale (GTK_IMAGE (ssimg->image1),
-                                                            pixbuf_bg, (gint) ssimg->scale);
+                                                            pixbuf, (gint) ssimg->scale);
                }
                gtk_stack_set_visible_child_name (GTK_STACK (ssimg->stack), "image1");
                ssimg->current_image = "image1";
@@ -369,14 +305,6 @@ gs_screenshot_image_set_size (GsScreenshotImage *ssimg,
        gtk_widget_set_size_request (ssimg->stack, (gint) width, (gint) height);
 }
 
-void
-gs_screenshot_image_set_use_desktop_background (GsScreenshotImage *ssimg,
-                                                gboolean use_desktop_background)
-{
-       g_return_if_fail (GS_IS_SCREENSHOT_IMAGE (ssimg));
-       ssimg->use_desktop_background = use_desktop_background;
-}
-
 static gchar *
 gs_screenshot_get_cachefn_for_url (const gchar *url)
 {
@@ -592,7 +520,6 @@ gs_screenshot_image_init (GsScreenshotImage *ssimg)
 {
        AtkObject *accessible;
 
-       ssimg->use_desktop_background = TRUE;
        ssimg->settings = g_settings_new ("org.gnome.software");
        ssimg->showing_image = FALSE;
 
diff --git a/src/gs-screenshot-image.h b/src/gs-screenshot-image.h
index b8d5521c..df9e41ad 100644
--- a/src/gs-screenshot-image.h
+++ b/src/gs-screenshot-image.h
@@ -28,9 +28,6 @@ void           gs_screenshot_image_set_screenshot     (GsScreenshotImage      *ssimg,
 void            gs_screenshot_image_set_size           (GsScreenshotImage      *ssimg,
                                                         guint                   width,
                                                         guint                   height);
-void            gs_screenshot_image_set_use_desktop_background
-                                                       (GsScreenshotImage      *ssimg,
-                                                        gboolean                use_desktop_background);
 void            gs_screenshot_image_load_async         (GsScreenshotImage      *ssimg,
                                                         GCancellable           *cancellable);