text: // Copyright 2013 The Chromium Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #ifndef CONTENT_BROWSER_RENDERER_HOST_INPUT_SYNTHETIC_SMOOTH_MOVE_GESTURE_H_
  #define CONTENT_BROWSER_RENDERER_HOST_INPUT_SYNTHETIC_SMOOTH_MOVE_GESTURE_H_
  
  #include <vector>
  
  #include "base/macros.h"
  #include "base/time/time.h"
  #include "content/browser/renderer_host/input/synthetic_gesture.h"
  #include "content/browser/renderer_host/input/synthetic_gesture_target.h"
  #include "content/browser/renderer_host/input/synthetic_pointer_driver.h"
  #include "content/common/content_export.h"
  #include "content/common/input/synthetic_smooth_drag_gesture_params.h"
  #include "content/common/input/synthetic_smooth_scroll_gesture_params.h"
  #include "third_party/blink/public/platform/web_input_event.h"
  #include "ui/gfx/geometry/vector2d.h"
  #include "ui/gfx/geometry/vector2d_f.h"
  
  namespace content {
  
  class CONTENT_EXPORT SyntheticSmoothMoveGestureParams {
   public:
    SyntheticSmoothMoveGestureParams();
    SyntheticSmoothMoveGestureParams(
        const SyntheticSmoothMoveGestureParams& other);
    ~SyntheticSmoothMoveGestureParams();
  
    enum InputType { MOUSE_DRAG_INPUT, MOUSE_WHEEL_INPUT, TOUCH_INPUT };
  
    InputType input_type;
    gfx::PointF start_point;
    std::vector<gfx::Vector2dF> distances;
    int speed_in_pixels_s;
    bool prevent_fling;
    bool add_slop;
  };
  
  // This class is used as helper class for simulation of scroll and drag.
  // Simulates scrolling/dragging given a sequence of distances as a continuous
  // gestures (i.e. when synthesizing touch or mouse drag events, the pointer is
  // not lifted when changing scroll direction).
  // If no distance is provided or the first one is 0, no touch events are
  // generated.
  // When synthesizing touch events for scrolling, the first distance is extended
  // to compensate for the touch slop.
  class CONTENT_EXPORT SyntheticSmoothMoveGesture : public SyntheticGesture {
   public:
    explicit SyntheticSmoothMoveGesture(SyntheticSmoothMoveGestureParams params);
    ~SyntheticSmoothMoveGesture() override;
  
    // SyntheticGesture implementation:
    SyntheticGesture::Result ForwardInputEvents(
        const base::TimeTicks& timestamp,
        SyntheticGestureTarget* target) override;
  
   private:
    enum GestureState {
      SETUP,
      STARTED,
      MOVING,
      STOPPING,
      DONE
    };
  
    void ForwardTouchInputEvents(
        const base::TimeTicks& timestamp, SyntheticGestureTarget* target);
    void ForwardMouseWheelInputEvents(
        const base::TimeTicks& timestamp, SyntheticGestureTarget* target);
    void ForwardMouseClickInputEvents(
        const base::TimeTicks& timestamp, SyntheticGestureTarget* target);
  
    void ForwardMouseWheelEvent(SyntheticGestureTarget* target,
                                const gfx::Vector2dF& delta,
                                const blink::WebMouseWheelEvent::Phase phase,
                                const base::TimeTicks& timestamp) const;
  
    void PressPoint(SyntheticGestureTarget* target,
                    const base::TimeTicks& timestamp);
    void MovePoint(SyntheticGestureTarget* target,
                   const gfx::Vector2dF& delta,
                   const base::TimeTicks& timestamp);
    void ReleasePoint(SyntheticGestureTarget* target,
                      const base::TimeTicks& timestamp);
  
    void AddTouchSlopToFirstDistance(SyntheticGestureTarget* target);
    gfx::Vector2dF GetPositionDeltaAtTime(const base::TimeTicks& timestamp) const;
    void ComputeNextMoveSegment();
    base::TimeTicks ClampTimestamp(const base::TimeTicks& timestamp) const;
    bool FinishedCurrentMoveSegment(const base::TimeTicks& timestamp) const;
    bool IsLastMoveSegment() const;
    bool MoveIsNoOp() const;
  
    SyntheticSmoothMoveGestureParams params_;
    std::unique_ptr<SyntheticPointerDriver> synthetic_pointer_driver_;
    // Used for mouse input.
    gfx::Vector2dF current_move_segment_total_delta_;
    // Used for touch input.
    gfx::PointF current_move_segment_start_position_;
    GestureState state_;
    int current_move_segment_;
    base::TimeTicks current_move_segment_start_time_;
    base::TimeTicks current_move_segment_stop_time_;
    // Used to set phase information for synthetic wheel events.
    bool needs_scroll_begin_;
  
    DISALLOW_COPY_AND_ASSIGN(SyntheticSmoothMoveGesture);
  };
  
  }  // namespace content
  
  #endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_SYNTHETIC_SMOOTH_MOVE_GESTURE_H_
  