GestureEvent.java

/*******************************************************************************
 * Copyright (c) 2010, 2011, 2012 IBM Corporation, Gerhardt Informatics Kft. and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Gerhardt Informatics Kft. - GEFGWT port
 *******************************************************************************/
package org.eclipse.swt.events;

import org.eclipse.swt.widgets.Event;

/**
 * Instances of this class are sent in response to touch-based gestures that are
 * triggered by the user.
 * 
 * @see GestureListener
 * @see <a href="http://www.eclipse.org/swt/">Sample code and further
 *      information</a>
 * 
 * @since 3.7
 */
public class GestureEvent extends TypedEvent {

	/**
	 * The state of the keyboard modifier keys and mouse masks at the time the
	 * event was generated.
	 * 
	 * @see org.eclipse.swt.SWT#MODIFIER_MASK
	 * @see org.eclipse.swt.SWT#BUTTON_MASK
	 */
	public int stateMask;

	/**
	 * The gesture type.
	 * <p>
	 * <ul>
	 * <li>{@link org.eclipse.swt.SWT#GESTURE_BEGIN}</li>
	 * <li>{@link org.eclipse.swt.SWT#GESTURE_END}</li>
	 * <li>{@link org.eclipse.swt.SWT#GESTURE_MAGNIFY}</li>
	 * <li>{@link org.eclipse.swt.SWT#GESTURE_PAN}</li>
	 * <li>{@link org.eclipse.swt.SWT#GESTURE_ROTATE}</li>
	 * <li>{@link org.eclipse.swt.SWT#GESTURE_SWIPE}</li>
	 * </ul>
	 * </p>
	 * 
	 * This field determines the <code>GestureEvent</code> fields that contain
	 * valid data.
	 */
	public int detail;

	/**
	 * The meaning of this field is dependent on the value of the
	 * <code>detail</code> field and the platform. It can represent either the x
	 * coordinate of the centroid of the touches that make up the gesture, or
	 * the x coordinate of the cursor at the time the gesture was performed.
	 */
	public int x;

	/**
	 * The meaning of this field is dependent on the value of the
	 * <code>detail</code> field and the platform. It can represent either the y
	 * coordinate of the centroid of the touches that make up the gesture, or
	 * the y coordinate of the cursor at the time the gesture was performed.
	 */
	public int y;

	/**
	 * This field is valid when the <code>detail</code> field is set to
	 * <code>GESTURE_ROTATE</code>. It specifies the number of degrees rotated
	 * on the device since the gesture started. Positive values indicate
	 * counter-clockwise rotation, and negative values indicate clockwise
	 * rotation.
	 */
	public double rotation;

	/**
	 * This field is valid when the <code>detail</code> field is set to
	 * <code>GESTURE_SWIPE</code> or <code>GESTURE_PAN</code>. Both
	 * <code>xDirection</code> and <code>yDirection</code> can be valid for an
	 * individual gesture. The meaning of this field is dependent on the value
	 * of the <code>detail</code> field.
	 * <p>
	 * If <code>detail</code> is <code>GESTURE_SWIPE</code> then a positive
	 * value indicates a swipe to the right and a negative value indicates a
	 * swipe to the left.
	 * 
	 * If <code>detail</code> is <code>GESTURE_PAN</code> then a positive value
	 * indicates a pan to the right by this field's count of pixels and a
	 * negative value indicates a pan to the left by this field's count of
	 * pixels.
	 */
	public int xDirection;

	/**
	 * This field is valid when the <code>detail</code> field is set to
	 * <code>GESTURE_SWIPE</code> or <code>GESTURE_PAN</code>. Both
	 * <code>xDirection</code> and <code>yDirection</code> can be valid for an
	 * individual gesture. The meaning of this field is dependent on the value
	 * of the <code>detail</code> field.
	 * 
	 * If <code>detail</code> is <code>GESTURE_SWIPE</code> then a positive
	 * value indicates a downward swipe and a negative value indicates an upward
	 * swipe.
	 * 
	 * If <code>detail</code> is <code>GESTURE_PAN</code> then a positive value
	 * indicates a downward pan by this field's count of pixels and a negative
	 * value indicates an upward pan by this field's count of pixels.
	 */
	public int yDirection;

	/**
	 * This field is valid when the <code>detail</code> field is set to
	 * <code>GESTURE_MAGNIFY</code>. This is the scale factor to be applied.
	 * This value will be 1.0 in the first received event with
	 * <code>GESTURE_MAGNIFY</code>, and will then fluctuate in subsequent
	 * events as the user moves their fingers.
	 */
	public double magnification;

	/**
	 * This flag indicates whether the operation should be allowed. Setting it
	 * to <code>false</code> will cancel the operation.
	 */
	public boolean doit;

	static final long serialVersionUID = -8348741538373572182L;

	/**
	 * Constructs a new instance of this class based on the information in the
	 * given untyped event.
	 * 
	 * @param e
	 *            the untyped event containing the information
	 */
	public GestureEvent(Event e) {
		super(e);
		this.stateMask = e.stateMask;
		this.x = e.x;
		this.y = e.y;
		this.detail = e.detail;
		this.rotation = e.rotation;
		this.xDirection = e.xDirection;
		this.yDirection = e.yDirection;
		this.magnification = e.magnification;
		this.doit = e.doit;
	}

	/**
	 * Returns a string containing a concise, human-readable description of the
	 * receiver.
	 * 
	 * @return a string representation of the event
	 */
	public String toString() {
		String string = super.toString();
		return string.substring(0, string.length() - 1) // remove trailing '}'
				+ " stateMask=" + stateMask + " detail=" + detail + " x="
				+ x
				+ " y=" + y + " rotation=" + rotation
				+ " xDirection="
				+ xDirection + " yDirection=" + yDirection
				+ " magnification="
				+ magnification + "}";
	}
}