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       float p0, float p1, float p2,
  30       const blink::WebSize& cumulativeScroll);
  31
  32  virtual bool apply(double monotonicTime,
  33                     blink::WebGestureCurveTarget*) OVERRIDE;
  34
  35  private:
  36   TouchFlingGestureCurve(const blink::WebFloatPoint& initial_velocity,
  37                          float p0,
  38                          float p1,
  39                          float p2,
  40                          const blink::WebSize& cumulativeScroll);
  41   virtual ~TouchFlingGestureCurve();
  42
  43   blink::WebFloatPoint displacement_ratio_;
  44   blink::WebFloatSize cumulative_scroll_;
  45   float coefficients_[3];
  46   float time_offset_;
  47   float curve_duration_;
  48   float position_offset_;
  49
  50   DISALLOW_COPY_AND_ASSIGN(TouchFlingGestureCurve);
  51 };
  52
  53 } // namespace content
  54
  55 #endif // CONTENT_CHILD_TOUCH_FLING_GESTURE_CURVE_H_