wip: Add lightboxes to graphics offload

Add GTK_GRAHPICS_OFFLOAD_ENABLED_WITH_LIGHTBOX, and pass that
on to the subsurface.

gdk/gdksubsurface.c

@@ -114,6 +114,7 @@ gdk_subsurface_attach (GdkSubsurface         *subsurface,
                        const graphene_rect_t *source,
                        const graphene_rect_t *dest,
                        GdkTextureTransform    transform,
+                       gboolean               lightbox,
                        gboolean               above,
                        GdkSubsurface         *sibling)
 {
@@ -156,7 +157,7 @@ gdk_subsurface_attach (GdkSubsurface         *subsurface,
         }
     }
 
-  return GDK_SUBSURFACE_GET_CLASS (subsurface)->attach (subsurface, texture, source, dest, transform, above, sibling);
+  return GDK_SUBSURFACE_GET_CLASS (subsurface)->attach (subsurface, texture, source, dest, transform, lightbox, above, sibling);
 }
 
 void
@@ -213,3 +214,10 @@ gdk_subsurface_get_transform (GdkSubsurface *subsurface)
   return GDK_SUBSURFACE_GET_CLASS (subsurface)->get_transform (subsurface);
 }
 
+gboolean
+gdk_subsurface_get_lightbox (GdkSubsurface *subsurface)
+{
+  g_return_val_if_fail (GDK_IS_SUBSURFACE (subsurface), FALSE);
+
+  return GDK_SUBSURFACE_GET_CLASS (subsurface)->get_lightbox (subsurface);
+}

gdk/gdksubsurfaceprivate.h

@@ -67,6 +67,7 @@ struct _GdkSubsurfaceClass
                                     const graphene_rect_t *source,
                                     const graphene_rect_t *dest,
                                     GdkTextureTransform    transform,
+                                    gboolean               lightbox,
                                     gboolean               above,
                                     GdkSubsurface         *sibling);
   void         (* detach)          (GdkSubsurface         *subsurface);
@@ -77,6 +78,7 @@ struct _GdkSubsurfaceClass
                                     graphene_rect_t       *dest);
   GdkTextureTransform
                (* get_transform)   (GdkSubsurface         *subsurface);
+  gboolean     (* get_lightbox)    (GdkSubsurface         *subsurface);
 };
 
 GType           gdk_subsurface_get_type        (void) G_GNUC_CONST;
@@ -88,6 +90,7 @@ gboolean        gdk_subsurface_attach          (GdkSubsurface         *subsurfac
                                                 const graphene_rect_t *source,
                                                 const graphene_rect_t *dest,
                                                 GdkTextureTransform    transform,
+                                                gboolean               lightbox,
                                                 gboolean               above,
                                                 GdkSubsurface         *sibling);
 void            gdk_subsurface_detach          (GdkSubsurface         *subsurface);
@@ -99,6 +102,7 @@ void            gdk_subsurface_get_dest        (GdkSubsurface         *subsurfac
 gboolean        gdk_subsurface_is_above_parent (GdkSubsurface         *subsurface);
 GdkTextureTransform
                 gdk_subsurface_get_transform   (GdkSubsurface         *subsurface);
+gboolean        gdk_subsurface_get_lightbox    (GdkSubsurface         *subsurface);
 
 
 G_END_DECLS

gdk/wayland/gdksubsurface-wayland-private.h

@@ -25,6 +25,7 @@ struct _GdkWaylandSubsurface
   cairo_rectangle_int_t dest;
   graphene_rect_t source;
   enum wl_output_transform transform;
+  gboolean lightbox;
 
   struct wl_region *opaque_region;
 

gdk/wayland/gdksubsurface-wayland.c

@@ -168,6 +168,7 @@ gdk_wayland_subsurface_attach (GdkSubsurface         *sub,
                                const graphene_rect_t *dest,
                                GdkTextureTransform    transform,
                                gboolean               above,
+                               gboolean               lightbox,
                                GdkSubsurface         *sibling)
 {
   GdkWaylandSubsurface *self = GDK_WAYLAND_SUBSURFACE (sub);
@@ -202,6 +203,7 @@ gdk_wayland_subsurface_attach (GdkSubsurface         *sub,
   self->source.size.height = source->size.height;
 
   self->transform = gdk_texture_transform_to_wl (transform);
+  self->lightbox = lightbox;
 
   scale = gdk_fractional_scale_to_double (&parent->scale);
 
@@ -430,6 +432,14 @@ gdk_wayland_subsurface_get_transform (GdkSubsurface *sub)
   return wl_output_transform_to_gdk (self->transform);
 }
 
+static gboolean
+gdk_wayland_subsurface_get_lightbox (GdkSubsurface *sub)
+{
+  GdkWaylandSubsurface *self = GDK_WAYLAND_SUBSURFACE (sub);
+
+  return self->lightbox;
+}
+
 static void
 gdk_wayland_subsurface_class_init (GdkWaylandSubsurfaceClass *class)
 {
@@ -444,6 +454,7 @@ gdk_wayland_subsurface_class_init (GdkWaylandSubsurfaceClass *class)
   subsurface_class->get_source = gdk_wayland_subsurface_get_source;
   subsurface_class->get_dest = gdk_wayland_subsurface_get_dest;
   subsurface_class->get_transform = gdk_wayland_subsurface_get_transform;
+  subsurface_class->get_lightbox = gdk_wayland_subsurface_get_lightbox;
 };
 
 static void

gsk/gskoffload.c

@@ -82,34 +82,59 @@ find_texture_transform (GskTransform *transform)
 
 static GdkTexture *
 find_texture_to_attach (GskOffload          *self,
-                        GdkSubsurface       *subsurface,
-                        const GskRenderNode *node,
+                        const GskRenderNode *subsurface_node,
                         graphene_rect_t     *out_clip,
-                        GdkTextureTransform *out_texture_transform)
+                        GdkTextureTransform *out_texture_transform,
+                        gboolean            *out_lightbox)
 {
+  GdkSubsurface *subsurface;
+  const GskRenderNode *node;
   gboolean has_clip = FALSE;
   graphene_rect_t clip;
   GskTransform *transform = NULL;
   GdkTexture *ret = NULL;
 
+  *out_texture_transform = GDK_TEXTURE_TRANSFORM_NORMAL;
+  *out_lightbox = FALSE;
+
+  subsurface = gsk_subsurface_node_get_subsurface (subsurface_node);
+  node = subsurface_node;
+
   for (;;)
     {
       switch ((int) GSK_RENDER_NODE_TYPE (node))
         {
         case GSK_DEBUG_NODE:
+        case GSK_SUBSURFACE_NODE:
           node = gsk_debug_node_get_child (node);
           break;
 
         case GSK_CONTAINER_NODE:
-          if (gsk_container_node_get_n_children (node) != 1)
+          if (gsk_container_node_get_n_children (node) == 1)
             {
-              GDK_DISPLAY_DEBUG (gdk_surface_get_display (self->surface), OFFLOAD,
-                                 "Can't offload subsurface %p: too much content, container with %d children",
-                                 subsurface, gsk_container_node_get_n_children (node));
-              goto out;
+              node = gsk_container_node_get_child (node, 0);
+              break;
             }
-          node = gsk_container_node_get_child (node, 0);
-          break;
+          else if (gsk_container_node_get_n_children (node) == 2)
+            {
+              GskRenderNode *child;
+
+              child = gsk_container_node_get_child (node, 0);
+              if (GSK_RENDER_NODE_TYPE (child) == GSK_COLOR_NODE &&
+                  gsk_rect_equal (&child->bounds, &subsurface_node->bounds) &&
+                  gdk_rgba_equal (gsk_color_node_get_color (child), &(GdkRGBA) { 0, 0, 0, 1 }))
+                {
+                  g_print ("found lightbox\n");
+                  *out_lightbox = TRUE;
+                  node = gsk_container_node_get_child (node, 1);
+                  break;
+                }
+            }
+
+          GDK_DISPLAY_DEBUG (gdk_surface_get_display (self->surface), OFFLOAD,
+                             "Can't offload subsurface %p: too much content, container with %d children",
+                             subsurface, gsk_container_node_get_n_children (node));
+          goto out;
 
         case GSK_TRANSFORM_NODE:
           {
@@ -615,7 +640,7 @@ complex_clip:
           }
         else
           {
-            info->texture = find_texture_to_attach (self, subsurface, gsk_subsurface_node_get_child (node), &info->source, &info->transform);
+            info->texture = find_texture_to_attach (self, node, &info->source, &info->transform, &info->lightbox);
             if (info->texture)
               {
                 info->can_offload = TRUE;
@@ -691,6 +716,7 @@ gsk_offload_new (GdkSurface     *surface,
                                                         &info->source,
                                                         &info->dest,
                                                         info->transform,
+                                                        info->lightbox,
                                                         TRUE, NULL);
           else
             info->is_offloaded = gdk_subsurface_attach (info->subsurface,
@@ -698,6 +724,7 @@ gsk_offload_new (GdkSurface     *surface,
                                                         &info->source,
                                                         &info->dest,
                                                         info->transform,
+                                                        info->lightbox,
                                                         info->place_above != NULL,
                                                         info->place_above);
         }

gsk/gskoffloadprivate.h

@@ -34,6 +34,7 @@ typedef struct
   graphene_rect_t dest;
   graphene_rect_t source;
   GdkTextureTransform transform;
+  gboolean lightbox;
 
   guint was_offloaded : 1;
   guint can_offload   : 1;

gtk/gtkgraphicsoffload.c

@@ -208,6 +208,13 @@ gtk_graphics_offload_snapshot (GtkWidget   *widget,
   if (self->subsurface)
     gtk_snapshot_push_subsurface (snapshot, self->subsurface);
 
+  if (self->enabled == GTK_GRAPHICS_OFFLOAD_ENABLED_WITH_LIGHTBOX)
+    gtk_snapshot_append_color (snapshot,
+                               &(GdkRGBA) { 0, 0, 0, 1 },
+                               &GRAPHENE_RECT_INIT (0, 0,
+                                                    gtk_widget_get_width (widget),
+                                                    gtk_widget_get_height (widget)));
+
   gtk_widget_snapshot_child (widget, self->child, snapshot);
 
   if (self->subsurface)

gtk/gtkgraphicsoffload.h

@@ -57,6 +57,7 @@ typedef enum
 {
   GTK_GRAPHICS_OFFLOAD_ENABLED,
   GTK_GRAPHICS_OFFLOAD_DISABLED,
+  GTK_GRAPHICS_OFFLOAD_ENABLED_WITH_LIGHTBOX,
 } GtkGraphicsOffloadEnabled;
 
 GDK_AVAILABLE_IN_4_14

testsuite/gdk/subsurface.c

@@ -42,9 +42,9 @@ test_subsurface_stacking (void)
 
   texture = gdk_texture_new_from_resource ("/org/gtk/libgtk/icons/16x16/actions/media-eject.png");
 
-  gdk_subsurface_attach (sub0, texture, &TEXTURE_RECT (texture), &GRAPHENE_RECT_INIT (0, 0, 10, 10), GDK_TEXTURE_TRANSFORM_NORMAL, TRUE, NULL);
-  gdk_subsurface_attach (sub1, texture, &TEXTURE_RECT (texture), &GRAPHENE_RECT_INIT (0, 0, 10, 10), GDK_TEXTURE_TRANSFORM_NORMAL, TRUE, NULL);
-  gdk_subsurface_attach (sub2, texture, &TEXTURE_RECT (texture), &GRAPHENE_RECT_INIT (0, 0, 10, 10), GDK_TEXTURE_TRANSFORM_NORMAL, TRUE, NULL);
+  gdk_subsurface_attach (sub0, texture, &TEXTURE_RECT (texture), &GRAPHENE_RECT_INIT (0, 0, 10, 10), GDK_TEXTURE_TRANSFORM_NORMAL, FALSE, TRUE, NULL);
+  gdk_subsurface_attach (sub1, texture, &TEXTURE_RECT (texture), &GRAPHENE_RECT_INIT (0, 0, 10, 10), GDK_TEXTURE_TRANSFORM_NORMAL, FALSE, TRUE, NULL);
+  gdk_subsurface_attach (sub2, texture, &TEXTURE_RECT (texture), &GRAPHENE_RECT_INIT (0, 0, 10, 10), GDK_TEXTURE_TRANSFORM_NORMAL, FALSE, TRUE, NULL);
 
   g_assert_true (surface->subsurfaces_above == sub2);
   g_assert_true (sub2->sibling_below == NULL);
@@ -67,7 +67,7 @@ test_subsurface_stacking (void)
   g_assert_true (sub0->sibling_above == NULL);
   g_assert_true (sub0->above_parent);
 
-  gdk_subsurface_attach (sub2, texture, &TEXTURE_RECT (texture), &GRAPHENE_RECT_INIT (0, 0, 10, 10), GDK_TEXTURE_TRANSFORM_NORMAL, FALSE, NULL);
+  gdk_subsurface_attach (sub2, texture, &TEXTURE_RECT (texture), &GRAPHENE_RECT_INIT (0, 0, 10, 10), GDK_TEXTURE_TRANSFORM_NORMAL, FALSE, FALSE, NULL);
 
   g_assert_true (surface->subsurfaces_above == sub0);
   g_assert_true (sub0->sibling_below == NULL);
@@ -79,7 +79,7 @@ test_subsurface_stacking (void)
   g_assert_true (sub2->sibling_above == NULL);
   g_assert_false (sub2->above_parent);
 
-  gdk_subsurface_attach (sub1, texture, &TEXTURE_RECT (texture), &GRAPHENE_RECT_INIT (0, 0, 10, 10), GDK_TEXTURE_TRANSFORM_NORMAL, TRUE, sub2);
+  gdk_subsurface_attach (sub1, texture, &TEXTURE_RECT (texture), &GRAPHENE_RECT_INIT (0, 0, 10, 10), GDK_TEXTURE_TRANSFORM_NORMAL, FALSE, TRUE, sub2);
 
   g_assert_true (surface->subsurfaces_below == sub1);
   g_assert_true (sub1->sibling_above == NULL);