1 /*
2 * Copyright 2012 Daniel Kurka
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
5 * use this file except in compliance with the License. You may obtain a copy of
6 * the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations under
14 * the License.
15 */
16 package com.googlecode.mgwt.dom.client.recognizer.pinch;
17
18 import com.google.gwt.event.shared.GwtEvent;
19
20 /**
21 * A {@link PinchEvent} is fired when a user moves to finger on the display.
22 *
23 * A pinch event is fired around a center point which is calculated by looking
24 * at the two fingers producing the event.
25 *
26 * <p>
27 * if finger one is at x1, y1 and finger two is at x2, y2 the center point is
28 * (x1 + x2) / 2 and (y1 + y2) / 2
29 * </p>
30 *
31 *
32 * @author Daniel Kurka
33 *
34 */
35 public class PinchEvent extends GwtEvent<PinchHandler> {
36
37 private static final GwtEvent.Type<PinchHandler> TYPE = new Type<PinchHandler>();
38 private final int x;
39 private final int y;
40 private final double scaleFactor;
41
42 public static GwtEvent.Type<PinchHandler> getType() {
43 return TYPE;
44 }
45
46 /**
47 * Construct a pinch event
48 *
49 * @param x the mid point of the pinch in x
50 * @param y the mid point of the pinch in y
51 * @param scaleFactor the new scaling factor
52 */
53 public PinchEvent(int x, int y, double scaleFactor) {
54 this.x = x;
55 this.y = y;
56 this.scaleFactor = scaleFactor;
57 }
58
59 /*
60 * (non-Javadoc)
61 * @see com.google.gwt.event.shared.GwtEvent#getAssociatedType()
62 */
63 @Override
64 public com.google.gwt.event.shared.GwtEvent.Type<PinchHandler> getAssociatedType() {
65 return TYPE;
66 }
67
68 /*
69 * (non-Javadoc)
70 * @see com.google.gwt.event.shared.GwtEvent#dispatch(com.google.gwt.event.shared.EventHandler)
71 */
72 @Override
73 protected void dispatch(PinchHandler handler) {
74 handler.onPinch(this);
75
76 }
77
78 /**
79 * The x position of the center point of the pinch.
80 *
81 *
82 * @return the x position
83 */
84 public int getX() {
85 return x;
86 }
87
88 /**
89 * The y position of the center point of the pinch.
90 *
91 *
92 * @return the y position
93 */
94 public int getY() {
95 return y;
96 }
97
98 /**
99 * the new scale factor that can be applied for getting a zoom effect
100 *
101 * @return the scale factor
102 */
103 public double getScaleFactor() {
104 return scaleFactor;
105 }
106
107 }