ui/compositor/layer_delegate.h

   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
  11 namespace gfx {
  12 class Canvas;
  13 }
  14
  15 namespace ui {
  16
  17 // A delegate interface implemented by an object that renders to a Layer.
  18 class 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_