content/browser/android/overscroll_glow.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 CONTENT_BROWSER_ANDROID_OVERSCROLL_GLOW_H_
   6 #define CONTENT_BROWSER_ANDROID_OVERSCROLL_GLOW_H_
   7
   8 #include "base/memory/ref_counted.h"
   9 #include "base/memory/scoped_ptr.h"
  10 #include "base/time/time.h"
  11 #include "content/browser/android/edge_effect.h"
  12 #include "ui/gfx/size_f.h"
  13 #include "ui/gfx/vector2d_f.h"
  14
  15 class SkBitmap;
  16
  17 namespace cc {
  18 class Layer;
  19 }
  20
  21 namespace content {
  22
  23 /* |OverscrollGlow| mirrors its Android counterpart, OverscrollGlow.java.
  24  * Conscious tradeoffs were made to align this as closely as possible with the
  25  * original Android Java version.
  26  */
  27 class OverscrollGlow {
  28  public:
  29   // Create a new effect. If |enabled| is false, the effect will remain
  30   // deactivated until explicitly enabled.
  31   // Note: No resources will be allocated until the effect is both
  32   //       enabled and an overscroll event has occurred.
  33   static scoped_ptr<OverscrollGlow> Create(bool enabled);
  34
  35   ~OverscrollGlow();
  36
  37   // Enable the effect. If the effect was previously disabled, it will remain
  38   // dormant until subsequent calls to |OnOverscrolled()|.
  39   void Enable();
  40
  41   // Deactivate and detach the effect. Subsequent calls to |OnOverscrolled()| or
  42   // |Animate()| will have no effect.
  43   void Disable();
  44
  45   // Effect layers will be attached to |overscrolling_layer| if necessary.
  46   // |accumulated_overscroll| and |overscroll_delta| are in device pixels, while
  47   // |velocity| is in device pixels / second.
  48   // Returns true if the effect still needs animation ticks.
  49   bool OnOverscrolled(cc::Layer* overscrolling_layer,
  50                       base::TimeTicks current_time,
  51                       gfx::Vector2dF accumulated_overscroll,
  52                       gfx::Vector2dF overscroll_delta,
  53                       gfx::Vector2dF velocity);
  54
  55   // Returns true if the effect still needs animation ticks.
  56   // Note: The effect will detach itself when no further animation is required.
  57   bool Animate(base::TimeTicks current_time);
  58
  59   // Update the effect according to the most recent display parameters,
  60   // Note: All dimensions are in device pixels.
  61   struct DisplayParameters {
  62     DisplayParameters();
  63     gfx::SizeF size;
  64     float edge_offsets[EdgeEffect::EDGE_COUNT];
  65     float device_scale_factor;
  66   };
  67   void UpdateDisplayParameters(const DisplayParameters& params);
  68
  69
  70  private:
  71   enum Axis { AXIS_X, AXIS_Y };
  72
  73   OverscrollGlow(bool enabled);
  74
  75   // Returns whether the effect is initialized.
  76   bool InitializeIfNecessary();
  77   bool NeedsAnimate() const;
  78   void UpdateLayerAttachment(cc::Layer* parent);
  79   void Detach();
  80   void Pull(base::TimeTicks current_time, gfx::Vector2dF overscroll_delta);
  81   void Absorb(base::TimeTicks current_time,
  82               gfx::Vector2dF velocity,
  83               bool x_overscroll_started,
  84               bool y_overscroll_started);
  85   void Release(base::TimeTicks current_time);
  86   void ReleaseAxis(Axis axis, base::TimeTicks current_time);
  87
  88   EdgeEffect* GetOppositeEdge(int edge_index);
  89
  90   scoped_ptr<EdgeEffect> edge_effects_[EdgeEffect::EDGE_COUNT];
  91
  92   DisplayParameters display_params_;
  93   bool enabled_;
  94   bool initialized_;
  95
  96   scoped_refptr<cc::Layer> root_layer_;
  97
  98   DISALLOW_COPY_AND_ASSIGN(OverscrollGlow);
  99 };
 100
 101 }  // namespace content
 102
 103 #endif  // CONTENT_BROWSER_ANDROID_SCROLL_GLOW_H_