Add a way to release GL resources

The inspector may hold on to render nodes and textures
beyond the lifetime of the widget (and thus the GL
resources). To handle this situation, allow the widget
to explicitly release the GL resources, and make
the texture available on the clent-side as a cairo
surface. This lets the recorder still show the content
after the widget is gone.

gdk/gdktexture.c

@@ -443,6 +443,8 @@ struct _GdkGLTexture {
   GdkGLContext *context;
   int id;
 
+  cairo_surface_t *saved;
+
   GDestroyNotify destroy;
   gpointer data;
 };
@@ -458,10 +460,21 @@ gdk_gl_texture_dispose (GObject *object)
 {
   GdkGLTexture *self = GDK_GL_TEXTURE (object);
 
-  g_object_unref (self->context);
-
   if (self->destroy)
-    self->destroy (self->data);
+    {
+      self->destroy (self->data);
+      self->destroy = NULL;
+      self->data = NULL;
+    }
+
+  g_clear_object (&self->context);
+  self->id = 0;
+
+  if (self->saved)
+    {
+      cairo_surface_destroy (self->saved);
+      self->saved = NULL;
+    }
 
   G_OBJECT_CLASS (gdk_gl_texture_parent_class)->dispose (object);
 }
@@ -474,7 +487,6 @@ gdk_gl_texture_download (GdkTexture *texture,
   GdkGLTexture *self = GDK_GL_TEXTURE (texture);
   cairo_surface_t *surface;
   cairo_t *cr;
-  GdkWindow *window;
 
   surface = cairo_image_surface_create_for_data (data,
                                                  CAIRO_FORMAT_ARGB32,
@@ -482,8 +494,21 @@ gdk_gl_texture_download (GdkTexture *texture,
                                                  stride);
 
   cr = cairo_create (surface);
-  window = gdk_gl_context_get_window (self->context);
-  gdk_cairo_draw_from_gl (cr, window, self->id, GL_TEXTURE, 1, 0, 0, texture->width, texture->height);
+
+  if (self->saved)
+    {
+      cairo_set_source_surface (cr, self->saved, 0, 0);
+      cairo_paint (cr);
+    }
+  else
+    {
+      GdkWindow *window;
+
+      window = gdk_gl_context_get_window (self->context);
+      gdk_cairo_draw_from_gl (cr, window, self->id, GL_TEXTURE, 1, 0, 0,
+                              texture->width, texture->height);
+    }
+
   cairo_destroy (cr);
   cairo_surface_finish (surface);
   cairo_surface_destroy (surface);
@@ -516,6 +541,41 @@ gdk_gl_texture_get_id (GdkGLTexture *self)
   return self->id;
 }
 
+void
+gdk_texture_release_gl (GdkTexture *texture)
+{
+  GdkGLTexture *self;
+  GdkWindow *window;
+  cairo_t *cr;
+
+  g_return_if_fail (GDK_IS_GL_TEXTURE (texture));
+
+  self = GDK_GL_TEXTURE (texture);
+
+  g_return_if_fail (self->saved == NULL);
+
+  self->saved = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
+                                            texture->width, texture->height);
+
+  cr = cairo_create (self->saved);
+
+  window = gdk_gl_context_get_window (self->context);
+  gdk_cairo_draw_from_gl (cr, window, self->id, GL_TEXTURE, 1, 0, 0,
+                          texture->width, texture->height);
+
+  cairo_destroy (cr);
+
+  if (self->destroy)
+    {
+      self->destroy (self->data);
+      self->destroy = NULL;
+      self->data = NULL;
+    }
+
+  g_clear_object (&self->context);
+  self->id = 0;
+}
+
 /**
  * gdk_texture_new_for_pixbuf:
  * @pixbuf: a #GdkPixbuf

gdk/gdktexture.h

@@ -64,6 +64,9 @@ GdkTexture *            gdk_texture_new_for_gl                 (GdkGLContext
                                                                 GDestroyNotify   destroy,
                                                                 gpointer         data);
 
+GDK_AVAILABLE_IN_3_94
+void                    gdk_texture_release_gl                 (GdkTexture      *texture);
+
 GDK_AVAILABLE_IN_3_94
 int                     gdk_texture_get_width                  (GdkTexture      *texture);
 GDK_AVAILABLE_IN_3_94