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1 // Copyright 2013 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_RENDERER_HOST_INPUT_SYNTHETIC_SMOOTH_SCROLL_GESTURE_H_
6 #define CONTENT_BROWSER_RENDERER_HOST_INPUT_SYNTHETIC_SMOOTH_SCROLL_GESTURE_H_
7 
8 #include "base/time/time.h"
9 #include "content/browser/renderer_host/input/synthetic_gesture.h"
10 #include "content/browser/renderer_host/input/synthetic_gesture_target.h"
11 #include "content/common/content_export.h"
12 #include "content/common/input/synthetic_smooth_scroll_gesture_params.h"
13 #include "content/common/input/synthetic_web_input_event_builders.h"
14 #include "third_party/WebKit/public/web/WebInputEvent.h"
15 #include "ui/gfx/vector2d.h"
16 #include "ui/gfx/vector2d_f.h"
17 
18 namespace content {
19 
20 // Simulates scrolling given a sequence of scroll distances as a continuous
21 // gestures (i.e. when synthesizing touch events, the touch pointer is not
22 // lifted when changing scroll direction).
23 // If no distance is provided or the first one is 0, no touch events are
24 // generated.
25 // When synthesizing touch events, the first distance is extended to compensate
26 // for the touch slop.
27 class CONTENT_EXPORT SyntheticSmoothScrollGesture : public SyntheticGesture {
28  public:
29   explicit SyntheticSmoothScrollGesture(
30       const SyntheticSmoothScrollGestureParams& params);
31   virtual ~SyntheticSmoothScrollGesture();
32 
33   virtual SyntheticGesture::Result ForwardInputEvents(
34       const base::TimeTicks& timestamp,
35       SyntheticGestureTarget* target) OVERRIDE;
36 
37  private:
38   enum GestureState {
39     SETUP,
40     STARTED,
41     MOVING,
42     STOPPING,
43     DONE
44   };
45 
46   void ForwardTouchInputEvents(
47       const base::TimeTicks& timestamp, SyntheticGestureTarget* target);
48   void ForwardMouseInputEvents(
49       const base::TimeTicks& timestamp, SyntheticGestureTarget* target);
50 
51   void ForwardTouchEvent(SyntheticGestureTarget* target,
52                          const base::TimeTicks& timestamp);
53   void ForwardMouseWheelEvent(SyntheticGestureTarget* target,
54                               const gfx::Vector2dF& delta,
55                               const base::TimeTicks& timestamp) const;
56 
57   void PressTouchPoint(SyntheticGestureTarget* target,
58                        const base::TimeTicks& timestamp);
59   void MoveTouchPoint(SyntheticGestureTarget* target,
60                       const gfx::Vector2dF& delta,
61                       const base::TimeTicks& timestamp);
62   void ReleaseTouchPoint(SyntheticGestureTarget* target,
63                          const base::TimeTicks& timestamp);
64 
65   void AddTouchSlopToFirstDistance(SyntheticGestureTarget* target);
66   gfx::Vector2dF GetPositionDeltaAtTime(const base::TimeTicks& timestamp)
67       const;
68   void ComputeNextScrollSegment();
69   base::TimeTicks ClampTimestamp(const base::TimeTicks& timestamp) const;
70   bool FinishedCurrentScrollSegment(const base::TimeTicks& timestamp) const;
71   bool IsLastScrollSegment() const;
72   bool ScrollIsNoOp() const;
73 
74   SyntheticSmoothScrollGestureParams params_;
75   // Used for mouse input.
76   gfx::Vector2d current_scroll_segment_total_delta_discrete_;
77   // Used for touch input.
78   gfx::Point current_scroll_segment_start_position_;
79   SyntheticWebTouchEvent touch_event_;
80   SyntheticGestureParams::GestureSourceType gesture_source_type_;
81   GestureState state_;
82   int current_scroll_segment_;
83   base::TimeTicks current_scroll_segment_start_time_;
84   base::TimeTicks current_scroll_segment_stop_time_;
85 
86   DISALLOW_COPY_AND_ASSIGN(SyntheticSmoothScrollGesture);
87 };
88 
89 }  // namespace content
90 
91 #endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_SYNTHETIC_SMOOTH_SCROLL_GESTURE_H_
92