third_party/WebKit/Source/platform/PlatformGestureEvent.h

/*
 * Copyright (C) 2011 Apple Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef PlatformGestureEvent_h
#define PlatformGestureEvent_h

#include "platform/PlatformEvent.h"
#include "platform/geometry/FloatPoint.h"
#include "platform/geometry/IntPoint.h"
#include "platform/geometry/IntSize.h"
#include "wtf/Assertions.h"
#include <string.h>

namespace blink {

class PlatformGestureEvent : public PlatformEvent {
 public:
  PlatformGestureEvent() : PlatformEvent(PlatformEvent::GestureScrollBegin) {
    memset(&m_data, 0, sizeof(m_data));
  }

  PlatformGestureEvent(Type type,
                       const IntPoint& position,
                       const IntPoint& globalPosition,
                       const IntSize& area,
                       double timestamp,
                       bool shiftKey,
                       bool ctrlKey,
                       bool altKey,
                       bool metaKey)
      : PlatformEvent(type, shiftKey, ctrlKey, altKey, metaKey, timestamp),
        m_position(position),
        m_globalPosition(globalPosition),
        m_area(area) {
    memset(&m_data, 0, sizeof(m_data));
  }

  void setScrollGestureData(float deltaX,
                            float deltaY,
                            float velocityX,
                            float velocityY,
                            bool inertial,
                            bool preventPropagation,
                            int resendingPluginId) {
    ASSERT(type() == PlatformEvent::GestureScrollBegin ||
           type() == PlatformEvent::GestureScrollUpdate ||
           type() == PlatformEvent::GestureScrollEnd);
    if (type() != GestureScrollUpdate) {
      ASSERT(deltaX == 0);
      ASSERT(deltaY == 0);
      ASSERT(velocityX == 0);
      ASSERT(velocityY == 0);
      ASSERT(!preventPropagation);
    }

    if (type() == PlatformEvent::GestureScrollBegin)
      ASSERT(!inertial);

    m_data.m_scroll.m_deltaX = deltaX;
    m_data.m_scroll.m_deltaY = deltaY;
    m_data.m_scroll.m_velocityX = velocityX;
    m_data.m_scroll.m_velocityY = velocityY;
    m_data.m_scroll.m_inertial = inertial;
    m_data.m_scroll.m_resendingPluginId = resendingPluginId;
    m_data.m_scroll.m_preventPropagation = preventPropagation;
  }

  const IntPoint& position() const {
    return m_position;
  }  // PlatformWindow coordinates.
  const IntPoint& globalPosition() const {
    return m_globalPosition;
  }  // Screen coordinates.

  const IntSize& area() const { return m_area; }

  float deltaX() const {
    ASSERT(m_type == PlatformEvent::GestureScrollUpdate);
    return m_data.m_scroll.m_deltaX;
  }

  float deltaY() const {
    ASSERT(m_type == PlatformEvent::GestureScrollUpdate);
    return m_data.m_scroll.m_deltaY;
  }

  int tapCount() const {
    ASSERT(m_type == PlatformEvent::GestureTap);
    return m_data.m_tap.m_tapCount;
  }

  float velocityX() const {
    ASSERT(m_type == PlatformEvent::GestureScrollUpdate ||
           m_type == PlatformEvent::GestureFlingStart);
    return m_data.m_scroll.m_velocityX;
  }

  float velocityY() const {
    ASSERT(m_type == PlatformEvent::GestureScrollUpdate ||
           m_type == PlatformEvent::GestureFlingStart);
    return m_data.m_scroll.m_velocityY;
  }

  bool inertial() const {
    ASSERT(m_type == PlatformEvent::GestureScrollUpdate ||
           m_type == PlatformEvent::GestureScrollEnd);
    return m_data.m_scroll.m_inertial;
  }

  int resendingPluginId() const {
    if (m_type == PlatformEvent::GestureScrollUpdate ||
        m_type == PlatformEvent::GestureScrollBegin ||
        m_type == PlatformEvent::GestureScrollEnd)
      return m_data.m_scroll.m_resendingPluginId;

    // This function is called by *all* gesture event types in
    // GestureEvent::Create(), so we return -1 for all other types.
    return -1;
  }

  bool preventPropagation() const {
    ASSERT(m_type == PlatformEvent::GestureScrollUpdate);
    return m_data.m_scroll.m_preventPropagation;
  }

  float scale() const {
    ASSERT(m_type == PlatformEvent::GesturePinchUpdate);
    return m_data.m_pinchUpdate.m_scale;
  }

  void applyTouchAdjustment(const IntPoint& adjustedPosition) {
    // Update the window-relative position of the event so that the node that
    // was
    // ultimately hit is under this point (i.e. elementFromPoint for the client
    // co-ordinates in a 'click' event should yield the target). The global
    // position is intentionally left unmodified because it's intended to
    // reflect
    // raw co-ordinates unrelated to any content.
    m_position = adjustedPosition;
  }

  bool isScrollEvent() const {
    switch (m_type) {
      case GestureScrollBegin:
      case GestureScrollEnd:
      case GestureScrollUpdate:
      case GestureFlingStart:
      case GesturePinchBegin:
      case GesturePinchEnd:
      case GesturePinchUpdate:
        return true;
      case GestureTap:
      case GestureTapUnconfirmed:
      case GestureTapDown:
      case GestureShowPress:
      case GestureTapDownCancel:
      case GestureTwoFingerTap:
      case GestureLongPress:
      case GestureLongTap:
        return false;
      default:
        ASSERT_NOT_REACHED();
        return false;
    }
  }

 protected:
  IntPoint m_position;
  IntPoint m_globalPosition;
  IntSize m_area;

  union {
    struct {
      int m_tapCount;
    } m_tap;

    struct {
      float m_deltaX;
      float m_deltaY;
      float m_velocityX;
      float m_velocityY;
      int m_preventPropagation;
      bool m_inertial;
      int m_resendingPluginId;
    } m_scroll;

    struct {
      float m_scale;
    } m_pinchUpdate;
  } m_data;
};

}  // namespace blink

#endif  // PlatformGestureEvent_h