src/content/child/touch_fling_gesture_curve.h

   1 // Copyright 2014 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_CHILD_TOUCH_FLING_GESTURE_CURVE_H_
   6 #define CONTENT_CHILD_TOUCH_FLING_GESTURE_CURVE_H_
   7
   8 #include "content/common/content_export.h"
   9 #include "third_party/WebKit/public/platform/WebFloatPoint.h"
  10 #include "third_party/WebKit/public/platform/WebFloatSize.h"
  11 #include "third_party/WebKit/public/platform/WebGestureCurve.h"
  12 #include "third_party/WebKit/public/platform/WebSize.h"
  13
  14 namespace blink {
  15 class WebGestureCurveTarget;
  16 }
  17
  18 namespace content {
  19
  20 // Implementation of WebGestureCurve suitable for touch pad/screen-based
  21 // fling scroll. Starts with a flat velocity profile based on 'velocity', which
  22 // tails off to zero. Time is scaled to that duration of the fling is
  23 // proportional to the initial velocity.
  24 class TouchFlingGestureCurve : public blink::WebGestureCurve {
  25  public:
  26
  27   static CONTENT_EXPORT WebGestureCurve* Create(
  28       const blink::WebFloatPoint& initial_velocity,
  29       const blink::WebSize& cumulativeScroll);
  30
  31  virtual bool apply(double monotonicTime,
  32                     blink::WebGestureCurveTarget*) OVERRIDE;
  33
  34  private:
  35   TouchFlingGestureCurve(const blink::WebFloatPoint& initial_velocity,
  36                          const blink::WebSize& cumulativeScroll);
  37   virtual ~TouchFlingGestureCurve();
  38
  39   blink::WebFloatPoint displacement_ratio_;
  40   blink::WebFloatSize cumulative_scroll_;
  41   float time_offset_;
  42   float curve_duration_;
  43   float position_offset_;
  44
  45   DISALLOW_COPY_AND_ASSIGN(TouchFlingGestureCurve);
  46 };
  47
  48 } // namespace content
  49
  50 #endif // CONTENT_CHILD_TOUCH_FLING_GESTURE_CURVE_H_