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 // Delegate is notified any time the background changes.
  22 class ASH_EXPORT BackgroundAnimatorDelegate {
  23  public:
  24   virtual void UpdateBackground(int alpha) = 0;
  25
  26  protected:
  27   virtual ~BackgroundAnimatorDelegate() {}
  28 };
  29
  30 // BackgroundAnimator is used by the shelf to animate the background (alpha).
  31 class ASH_EXPORT BackgroundAnimator : public gfx::AnimationDelegate {
  32  public:
  33   BackgroundAnimator(BackgroundAnimatorDelegate* delegate,
  34                      int min_alpha,
  35                      int max_alpha);
  36   virtual ~BackgroundAnimator();
  37
  38   // Sets the transition time in ms.
  39   void SetDuration(int time_in_ms);
  40
  41   // Sets whether a background is rendered. Initial value is false. If |type|
  42   // is |CHANGE_IMMEDIATE| and an animation is not in progress this notifies
  43   // the delegate immediately (synchronously from this method).
  44   void SetPaintsBackground(bool value, BackgroundAnimatorChangeType type);
  45   bool paints_background() const { return paints_background_; }
  46
  47   // Current alpha.
  48   int alpha() const { return alpha_; }
  49
  50   // gfx::AnimationDelegate overrides:
  51   virtual void AnimationProgressed(const gfx::Animation* animation) OVERRIDE;
  52
  53  private:
  54   BackgroundAnimatorDelegate* delegate_;
  55
  56   const int min_alpha_;
  57   const int max_alpha_;
  58
  59   gfx::SlideAnimation animation_;
  60
  61   // Whether the background is painted.
  62   bool paints_background_;
  63
  64   // Current alpha value of the background.
  65   int alpha_;
  66
  67   DISALLOW_COPY_AND_ASSIGN(BackgroundAnimator);
  68 };
  69
  70 }  // namespace ash
  71
  72 #endif  // ASH_SHELF_BACKGROUND_ANIMATOR_H_