ash/shelf/background_animator.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 ASH_SHELF_BACKGROUND_ANIMATOR_H_
   6 #define ASH_SHELF_BACKGROUND_ANIMATOR_H_
   7
   8 #include "ash/ash_export.h"
   9 #include "base/basictypes.h"
  10 #include "ui/gfx/animation/animation_delegate.h"
  11 #include "ui/gfx/animation/slide_animation.h"
  12
  13 namespace ash {
  14
  15 // How the background can be changed.
  16 enum BackgroundAnimatorChangeType {
  17   BACKGROUND_CHANGE_ANIMATE,
  18   BACKGROUND_CHANGE_IMMEDIATE
  19 };
  20
  21 namespace internal {
  22
  23 // Delegate is notified any time the background changes.
  24 class ASH_EXPORT BackgroundAnimatorDelegate {
  25  public:
  26   virtual void UpdateBackground(int alpha) = 0;
  27
  28  protected:
  29   virtual ~BackgroundAnimatorDelegate() {}
  30 };
  31
  32 // BackgroundAnimator is used by the shelf to animate the background (alpha).
  33 class ASH_EXPORT BackgroundAnimator : public gfx::AnimationDelegate {
  34  public:
  35   BackgroundAnimator(BackgroundAnimatorDelegate* delegate,
  36                      int min_alpha,
  37                      int max_alpha);
  38   virtual ~BackgroundAnimator();
  39
  40   // Sets the transition time in ms.
  41   void SetDuration(int time_in_ms);
  42
  43   // Sets whether a background is rendered. Initial value is false. If |type|
  44   // is |CHANGE_IMMEDIATE| and an animation is not in progress this notifies
  45   // the delegate immediately (synchronously from this method).
  46   void SetPaintsBackground(bool value, BackgroundAnimatorChangeType type);
  47   bool paints_background() const { return paints_background_; }
  48
  49   // Current alpha.
  50   int alpha() const { return alpha_; }
  51
  52   // gfx::AnimationDelegate overrides:
  53   virtual void AnimationProgressed(const gfx::Animation* animation) OVERRIDE;
  54
  55  private:
  56   BackgroundAnimatorDelegate* delegate_;
  57
  58   const int min_alpha_;
  59   const int max_alpha_;
  60
  61   gfx::SlideAnimation animation_;
  62
  63   // Whether the background is painted.
  64   bool paints_background_;
  65
  66   // Current alpha value of the background.
  67   int alpha_;
  68
  69   DISALLOW_COPY_AND_ASSIGN(BackgroundAnimator);
  70 };
  71
  72 }  // namespace internal
  73 }  // namespace ash
  74
  75 #endif  // ASH_SHELF_BACKGROUND_ANIMATOR_H_