1 // Copyright 2011 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 CC_INPUT_PAGE_SCALE_ANIMATION_H_ 6 #define CC_INPUT_PAGE_SCALE_ANIMATION_H_ 7 8 #include "base/basictypes.h" 9 #include "base/memory/scoped_ptr.h" 10 #include "base/time/time.h" 11 #include "cc/base/cc_export.h" 12 #include "ui/gfx/size.h" 13 #include "ui/gfx/vector2d_f.h" 14 15 namespace cc { 16 17 class TimingFunction; 18 19 // A small helper class that does the math for zoom animations, primarily for 20 // double-tap zoom. Initialize it with starting and ending scroll/page scale 21 // positions and an animation length time, then call ...AtTime() at every frame 22 // to obtain the current interpolated position. The supplied timing function 23 // is used to ease the animation. 24 // 25 // All sizes and vectors in this class's public methods are in the root scroll 26 // layer's coordinate space. 27 class CC_EXPORT PageScaleAnimation { 28 public: 29 // Construct with the state at the beginning of the animation. 30 static scoped_ptr<PageScaleAnimation> Create( 31 const gfx::Vector2dF& start_scroll_offset, 32 float start_page_scale_factor, 33 const gfx::SizeF& viewport_size, 34 const gfx::SizeF& root_layer_size, 35 scoped_ptr<TimingFunction> timing_function); 36 37 ~PageScaleAnimation(); 38 39 // The following methods initialize the animation. Call one of them 40 // immediately after construction to set the final scroll and page scale. 41 42 // Zoom while explicitly specifying the top-left scroll position. 43 void ZoomTo(const gfx::Vector2dF& target_scroll_offset, 44 float target_page_scale_factor, 45 double duration); 46 47 // Zoom based on a specified anchor. The animator will attempt to keep it 48 // at the same position on the physical display throughout the animation, 49 // unless the edges of the root layer are hit. The anchor is specified 50 // as an offset from the content layer. 51 void ZoomWithAnchor(const gfx::Vector2dF& anchor, 52 float target_page_scale_factor, 53 double duration); 54 55 // These should be called before the first frame of animation to initialize 56 // the start time. StartAnimation should only be called once after creation. 57 bool IsAnimationStarted() const; 58 void StartAnimation(base::TimeTicks time); 59 60 // Call these functions while the animation is in progress to output the 61 // current state. 62 gfx::Vector2dF ScrollOffsetAtTime(base::TimeTicks time) const; 63 float PageScaleFactorAtTime(base::TimeTicks time) const; 64 bool IsAnimationCompleteAtTime(base::TimeTicks time) const; 65 66 // The following methods return state which is invariant throughout the 67 // course of the animation. start_time()68 base::TimeTicks start_time() const { return start_time_; } duration()69 base::TimeDelta duration() const { return duration_; } end_time()70 base::TimeTicks end_time() const { return start_time_ + duration_; } target_scroll_offset()71 gfx::Vector2dF target_scroll_offset() const { return target_scroll_offset_; } target_page_scale_factor()72 float target_page_scale_factor() const { return target_page_scale_factor_; } 73 74 protected: 75 PageScaleAnimation(const gfx::Vector2dF& start_scroll_offset, 76 float start_page_scale_factor, 77 const gfx::SizeF& viewport_size, 78 const gfx::SizeF& root_layer_size, 79 scoped_ptr<TimingFunction> timing_function); 80 81 private: 82 void ClampTargetScrollOffset(); 83 void InferTargetScrollOffsetFromStartAnchor(); 84 void InferTargetAnchorFromScrollOffsets(); 85 86 gfx::SizeF StartViewportSize() const; 87 gfx::SizeF TargetViewportSize() const; 88 float InterpAtTime(base::TimeTicks time) const; 89 gfx::SizeF ViewportSizeAt(float interp) const; 90 gfx::Vector2dF ScrollOffsetAt(float interp) const; 91 gfx::Vector2dF AnchorAt(float interp) const; 92 gfx::Vector2dF ViewportRelativeAnchorAt(float interp) const; 93 float PageScaleFactorAt(float interp) const; 94 95 float start_page_scale_factor_; 96 float target_page_scale_factor_; 97 gfx::Vector2dF start_scroll_offset_; 98 gfx::Vector2dF target_scroll_offset_; 99 100 gfx::Vector2dF start_anchor_; 101 gfx::Vector2dF target_anchor_; 102 103 gfx::SizeF viewport_size_; 104 gfx::SizeF root_layer_size_; 105 106 base::TimeTicks start_time_; 107 base::TimeDelta duration_; 108 109 scoped_ptr<TimingFunction> timing_function_; 110 111 DISALLOW_COPY_AND_ASSIGN(PageScaleAnimation); 112 }; 113 114 } // namespace cc 115 116 #endif // CC_INPUT_PAGE_SCALE_ANIMATION_H_ 117