Animated Rotation

ui/gfx/compositor/compositor.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_GFX_COMPOSITOR_COMPOSITOR_H_
 #define UI_GFX_COMPOSITOR_COMPOSITOR_H_
 #pragma once
 
 #include "base/memory/ref_counted.h"
+#include "base/observer_list.h"
 #include "ui/gfx/compositor/compositor_export.h"
 #include "ui/gfx/transform.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gfx/size.h"
 
 class SkCanvas;
 namespace gfx {
 class Point;
 class Rect;
 }
 
 namespace ui {
 
+class CompositorObserver;
+
 struct TextureDrawParams {
   TextureDrawParams() : transform(), blend(false), compositor_size() {}
 
   // The transform to be applied to the texture.
   ui::Transform transform;
 
   // If this is true, then the texture is blended with the pixels behind it.
   // Otherwise, the drawn pixels clobber the old pixels.
   bool blend;
 
@@ skipping 41 matching lines @@
 class COMPOSITOR_EXPORT Compositor : public base::RefCounted<Compositor> {
  public:
   // Create a compositor from the provided handle.
   static Compositor* Create(gfx::AcceleratedWidget widget,
                             const gfx::Size& size);
 
   // Creates a new texture. The caller owns the returned object.
   virtual Texture* CreateTexture() = 0;
 
   // Notifies the compositor that compositing is about to start.
-  virtual void NotifyStart() = 0;
+  void NotifyStart();
 
   // Notifies the compositor that compositing is complete.
-  virtual void NotifyEnd() = 0;
+  void NotifyEnd();
 
   // Blurs the specific region in the compositor.
   virtual void Blur(const gfx::Rect& bounds) = 0;
 
   // Schedules a paint on the widget this Compositor was created for.
   virtual void SchedulePaint() = 0;
 
   // Notifies the compositor that the size of the widget that it is
   // drawing to has changed.
   void WidgetSizeChanged(const gfx::Size& size) {
     size_ = size;
     OnWidgetSizeChanged();
   }
 
   // Returns the size of the widget that is being drawn to.
   const gfx::Size& size() { return size_; }
 
+  // Layers do not own observers. It is the responsibility of the observer to
+  // remove itself when it is done observing.
+  void AddObserver(CompositorObserver* observer);
+  void RemoveObserver(CompositorObserver* observer);
+
  protected:
   explicit Compositor(const gfx::Size& size) : size_(size) {}
   virtual ~Compositor() {}
 
+  // Notifies the compositor that compositing is about to start.
+  virtual void OnNotifyStart() = 0;
+
+  // Notifies the compositor that compositing is complete.
+  virtual void OnNotifyEnd() = 0;
+
   virtual void OnWidgetSizeChanged() = 0;
 
  private:
   gfx::Size size_;
 
+  ObserverList<CompositorObserver> observer_list_;
+
   friend class base::RefCounted<Compositor>;
 };
 
 }  // namespace ui
 
 #endif  // UI_GFX_COMPOSITOR_COMPOSITOR_H_