[clutter/clutter-1.16] canvas: Allow invalidating the content along with the size

[Emmanuele Bassi <ebassi src gnome org>]

commit 264c67c2aa64cc1f6de6c1e9c7e8de16e01b3607
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Thu Apr 11 13:05:03 2013 +0100

    canvas: Allow invalidating the content along with the size
    
    Currently, clutter_canvas_set_size() causes invalidation of the canvas
    contents only if the newly set size is different. There are cases when
    we want to invalidate the content regardless of the size set, but we
    cannot do that right now without possibly causing two invalidations,
    for instance:
    
      clutter_canvas_set_size (canvas, new_width, new_height);
      clutter_content_invalidate (canvas);
    
    will cause two invalidations if the newly set size is different than
    the existing one. One way to work around it is to check the current
    size of the canvas and either call set_size() or invalidate() depending
    on whether the size differs or not, respectively:
    
      g_object_get (canvas, "width", &width, "height", &height, NULL);
      if (width != new_width || height != new_height)
        clutter_canvas_set_size (canvas, new_width, new_height);
      else
        clutter_content_invalidate (canvas);
    
    this, howevere, implies knowledge of the internals of ClutterCanvas,
    and of its optimizations — and encodes a certain behaviour in third
    party code, which makes changes further down the line harder.
    
    We could remove the optimization, and just issue an invalidation
    regardless of the surface size, but it's not something I'd be happy to
    do. Instead, we can add a new function specifically for ClutterCanvas
    that causes a forced invalidation regardless of the size change. If we
    ever decide to remove the optimization further down the road, we can
    simply deprecate the function, and make it an alias of invalidate()
    or set_size().

 clutter/clutter-canvas.c |   76 +++++++++++++++++++++++++++++++++-------------
 clutter/clutter-canvas.h |   13 +++++--
 2 files changed, 64 insertions(+), 25 deletions(-)
---
diff --git a/clutter/clutter-canvas.c b/clutter/clutter-canvas.c
index 43c0e75..f1f92eb 100644
--- a/clutter/clutter-canvas.c
+++ b/clutter/clutter-canvas.c
@@ -494,28 +494,14 @@ clutter_canvas_new (void)
   return g_object_new (CLUTTER_TYPE_CANVAS, NULL);
 }
 
-/**
- * clutter_canvas_set_size:
- * @canvas: a #ClutterCanvas
- * @width: the width of the canvas, in pixels
- * @height: the height of the canvas, in pixels
- *
- * Sets the size of the @canvas.
- *
- * This function will cause the @canvas to be invalidated.
- *
- * Since: 1.10
- */
-void
-clutter_canvas_set_size (ClutterCanvas *canvas,
-                         int            width,
-                         int            height)
+static inline void
+clutter_canvas_invalidate_internal (ClutterCanvas *canvas,
+                                    int            width,
+                                    int            height,
+                                    gboolean       force_invalidate)
 {
-  GObject *obj;
   gboolean width_changed = FALSE, height_changed = FALSE;
-
-  g_return_if_fail (CLUTTER_IS_CANVAS (canvas));
-  g_return_if_fail (width >= -1 && height >= -1);
+  GObject *obj;
 
   obj = G_OBJECT (canvas);
 
@@ -537,8 +523,56 @@ clutter_canvas_set_size (ClutterCanvas *canvas,
       g_object_notify_by_pspec (obj, obj_props[PROP_HEIGHT]);
     }
 
-  if (width_changed || height_changed)
+  if (force_invalidate || (width_changed || height_changed))
     clutter_content_invalidate (CLUTTER_CONTENT (canvas));
 
   g_object_thaw_notify (obj);
 }
+
+/**
+ * clutter_canvas_set_size:
+ * @canvas: a #ClutterCanvas
+ * @width: the width of the canvas, in pixels
+ * @height: the height of the canvas, in pixels
+ *
+ * Sets the size of the @canvas, and invalidates the content.
+ *
+ * This function will cause the @canvas to be invalidated only
+ * if the size of the canvas surface has changed.
+ *
+ * Since: 1.10
+ */
+void
+clutter_canvas_set_size (ClutterCanvas *canvas,
+                         int            width,
+                         int            height)
+{
+  g_return_if_fail (CLUTTER_IS_CANVAS (canvas));
+  g_return_if_fail (width >= -1 && height >= -1);
+
+  clutter_canvas_invalidate_internal (canvas, width, height, FALSE);
+}
+
+/**
+ * clutter_canvas_invalidate_with_size:
+ * @canvas: a #ClutterCanvas
+ * @width: the width of the canvas, in pixels
+ * @height: the height of the canvas, in pixels
+ *
+ * Sets the size of the @canvas, and invalidates the content.
+ *
+ * This function will cause the @canvas to be invalidated regardless
+ * of the size change.
+ *
+ * Since: 1.16
+ */
+void
+clutter_canvas_invalidate_with_size (ClutterCanvas *canvas,
+                                     int            width,
+                                     int            height)
+{
+  g_return_if_fail (CLUTTER_IS_CANVAS (canvas));
+  g_return_if_fail (width >= -1 && height >= -1);
+
+  clutter_canvas_invalidate_internal (canvas, width, height, TRUE);
+}
diff --git a/clutter/clutter-canvas.h b/clutter/clutter-canvas.h
index c0c27fd..e607150 100644
--- a/clutter/clutter-canvas.h
+++ b/clutter/clutter-canvas.h
@@ -89,11 +89,16 @@ CLUTTER_AVAILABLE_IN_1_10
 GType clutter_canvas_get_type (void) G_GNUC_CONST;
 
 CLUTTER_AVAILABLE_IN_1_10
-ClutterContent *        clutter_canvas_new              (void);
+ClutterContent *        clutter_canvas_new                      (void);
 CLUTTER_AVAILABLE_IN_1_10
-void                    clutter_canvas_set_size         (ClutterCanvas *canvas,
-                                                         int            width,
-                                                         int            height);
+void                    clutter_canvas_set_size                 (ClutterCanvas *canvas,
+                                                                 int            width,
+                                                                 int            height);
+
+CLUTTER_AVAILABLE_IN_1_16
+void                    clutter_canvas_invalidate_with_size     (ClutterCanvas *canvas,
+                                                                 int            width,
+                                                                 int            height);
 
 G_END_DECLS