layer_delegate.h revision 5821806d5e7f356e8fa4b058a389a808ea183019 
1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef UI_COMPOSITOR_LAYER_DELEGATE_H_
6#define UI_COMPOSITOR_LAYER_DELEGATE_H_
7
8#include "base/callback_forward.h"
9#include "ui/compositor/compositor_export.h"
10
11namespace gfx {
12class Canvas;
13}
14
15namespace ui {
16
17// A delegate interface implemented by an object that renders to a Layer.
18class COMPOSITOR_EXPORT LayerDelegate {
19 public:
20  // Paint content for the layer to the specified canvas. It has already been
21  // clipped to the Layer's invalid rect.
22  virtual void OnPaintLayer(gfx::Canvas* canvas) = 0;
23
24  // Called when the layer's device scale factor has changed.
25  virtual void OnDeviceScaleFactorChanged(float device_scale_factor) = 0;
26
27  // Invoked prior to the bounds changing. The returned closured is run after
28  // the bounds change.
29  virtual base::Closure PrepareForLayerBoundsChange() = 0;
30
31 protected:
32  virtual ~LayerDelegate() {}
33};
34
35}  // namespace ui
36
37#endif  // UI_COMPOSITOR_LAYER_DELEGATE_H_
38