/******************************************************************************* * Copyright (c) 2000, 2004 IBM Corporation and others. * All rights reserved. This program and the accompanying materials * are made available under the terms of the Common Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/cpl-v10.html *  * Contributors: *     IBM Corporation - initial API and implementation *******************************************************************************/package org.eclipse.swt.graphics;import org.eclipse.swt.internal.SerializableCompatibility;import org.eclipse.swt.*;/** * Instances of this class represent rectangular areas in an * (x, y) coordinate system. The top left corner of the rectangle * is specified by its x and y values, and the extent of the * rectangle is specified by its width and height. * <p> * The coordinate space for rectangles and points is considered * to have increasing values downward and to the right from its * origin making this the normal, computer graphics oriented notion * of (x, y) coordinates rather than the strict mathematical one. * </p> * <p> * The hashCode() method in this class uses the values of the public * fields to compute the hash value. When storing instances of the * class in hashed collections, do not modify these fields after the * object has been inserted.   * </p> * <p> * Application code does <em>not</em> need to explicitly release the * resources managed by each instance when those instances are no longer * required, and thus no <code>dispose()</code> method is provided. * </p> * * @see Point */public final class Rectangle implements SerializableCompatibility {		/**	 * the x coordinate of the rectangle	 */	public int x;		/**	 * the y coordinate of the rectangle	 */	public int y;		/**	 * the width of the rectangle	 */	public int width;		/**	 * the height of the rectangle	 */	public int height;/** * Construct a new instance of this class given the  * x, y, width and height values. * * @param x the x coordinate of the origin of the rectangle * @param y the y coordinate of the origin of the rectangle * @param width the width of the rectangle * @param height the height of the rectangle */public Rectangle (int x, int y, int width, int height) {	this.x = x;	this.y = y;	this.width = width;	this.height = height;}/** * Destructively replaces the x, y, width and height values * in the receiver with ones which represent the union of the * rectangles specified by the receiver and the given rectangle. * <p> * The union of two rectangles is the smallest single rectangle * that completely covers both of the areas covered by the two * given rectangles. * </p> * * @param rect the rectangle to merge with the receiver * * @exception IllegalArgumentException <ul> *    <li>ERROR_NULL_ARGUMENT - if the argument is null</li> * </ul> */public void add (Rectangle rect) {	if (rect == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);	int left = x < rect.x ? x : rect.x;	int top = y < rect.y ? y : rect.y;	int lhs = x + width;	int rhs = rect.x + rect.width;	int right = lhs > rhs ? lhs : rhs;	lhs = y + height;	rhs = rect.y + rect.height;	int bottom = lhs > rhs ? lhs : rhs;	x = left;  y = top;  width = right - left;  height = bottom - top;}/** * Returns <code>true</code> if the point specified by the * arguments is inside the area specified by the receiver, * and <code>false</code> otherwise. * * @param x the x coordinate of the point to test for containment * @param y the y coordinate of the point to test for containment * @return <code>true</code> if the rectangle contains the point and <code>false</code> otherwise */public boolean contains (int x, int y) {	return (x >= this.x) && (y >= this.y) && ((x - this.x) < width) && ((y - this.y) < height);}/** * Returns <code>true</code> if the given point is inside the * area specified by the receiver, and <code>false</code> * otherwise. * * @param pt the point to test for containment * @return <code>true</code> if the rectangle contains the point and <code>false</code> otherwise * * @exception IllegalArgumentException <ul> *    <li>ERROR_NULL_ARGUMENT - if the argument is null</li> * </ul> */public boolean contains (Point pt) {	if (pt == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);	return contains(pt.x, pt.y);}/** * Compares the argument to the receiver, and returns true * if they represent the <em>same</em> object using a class * specific comparison. * * @param object the object to compare with this object * @return <code>true</code> if the object is the same as this object and <code>false</code> otherwise * * @see #hashCode() */public boolean equals (Object object) {	if (object == this) return true;	if (!(object instanceof Rectangle)) return false;	Rectangle r = (Rectangle)object;	return (r.x == this.x) && (r.y == this.y) && (r.width == this.width) && (r.height == this.height);}/** * Returns an integer hash code for the receiver. Any two  * objects which return <code>true</code> when passed to  * <code>equals</code> must return the same value for this * method. * * @return the receiver's hash * * @see #equals(Object) */public int hashCode () {	return x ^ y ^ width ^ height;}/** * Destructively replaces the x, y, width and height values * in the receiver with ones which represent the intersection of the * rectangles specified by the receiver and the given rectangle. * * @param rect the rectangle to intersect with the receiver * * @exception IllegalArgumentException <ul> *    <li>ERROR_NULL_ARGUMENT - if the argument is null</li> * </ul> *  * since 3.0 */public void intersect (Rectangle rect) {	if (rect == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);	if (this == rect) return;	int left = x > rect.x ? x : rect.x;	int top = y > rect.y ? y : rect.y;	int lhs = x + width;	int rhs = rect.x + rect.width;	int right = lhs < rhs ? lhs : rhs;	lhs = y + height;	rhs = rect.y + rect.height;	int bottom = lhs < rhs ? lhs : rhs;	x = right < left ? 0 : left;	y = bottom < top ? 0 : top;	width = right < left ? 0 : right - left;	height = bottom < top ? 0 : bottom - top;}/** * Returns a new rectangle which represents the intersection * of the receiver and the given rectangle.  * <p> * The intersection of two rectangles is the rectangle that * covers the area which is contained within both rectangles. * </p> * * @param rect the rectangle to intersect with the receiver * @return the intersection of the receiver and the argument * * @exception IllegalArgumentException <ul> *    <li>ERROR_NULL_ARGUMENT - if the argument is null</li> * </ul> */public Rectangle intersection (Rectangle rect) {	if (rect == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);	if (this == rect) return new Rectangle (x, y, width, height);	int left = x > rect.x ? x : rect.x;	int top = y > rect.y ? y : rect.y;	int lhs = x + width;	int rhs = rect.x + rect.width;	int right = lhs < rhs ? lhs : rhs;	lhs = y + height;	rhs = rect.y + rect.height;	int bottom = lhs < rhs ? lhs : rhs;	return new Rectangle (		right < left ? 0 : left,		bottom < top ? 0 : top,		right < left ? 0 : right - left,		bottom < top ? 0 : bottom - top);}/** * Returns <code>true</code> if the rectangle described by the * arguments intersects with the receiver and <code>false</code> * otherwise. * <p> * Two rectangles intersect if the area of the rectangle * representing their intersection is not empty. * </p> * * @param x the x coordinate of the origin of the rectangle * @param y the y coordinate of the origin of the rectangle * @param width the width of the rectangle * @param height the height of the rectangle * @return <code>true</code> if the rectangle intersects with the receiver, and <code>false</code> otherwise * * @exception IllegalArgumentException <ul> *    <li>ERROR_NULL_ARGUMENT - if the argument is null</li> * </ul> * * @see #intersection(Rectangle) * @see #isEmpty() *  * @since 3.0 */public boolean intersects (int x, int y, int width, int height) {	return (x < this.x + this.width) && (y < this.y + this.height) &&		(x + width > this.x) && (y + height > this.y);}/** * Returns <code>true</code> if the given rectangle intersects * with the receiver and <code>false</code> otherwise. * <p> * Two rectangles intersect if the area of the rectangle * representing their intersection is not empty. * </p> * * @param rect the rectangle to test for intersection * @return <code>true</code> if the rectangle intersects with the receiver, and <code>false</code> otherwise * * @exception IllegalArgumentException <ul> *    <li>ERROR_NULL_ARGUMENT - if the argument is null</li> * </ul> * * @see #intersection(Rectangle) * @see #isEmpty() */public boolean intersects (Rectangle rect) {	if (rect == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);	return rect == this || intersects (rect.x, rect.y, rect.width, rect.height);}		/** * Returns <code>true</code> if the receiver does not cover any * area in the (x, y) coordinate plane, and <code>false</code> if * the receiver does cover some area in the plane. * <p> * A rectangle is considered to <em>cover area</em> in the  * (x, y) coordinate plane if both its width and height are  * non-zero. * </p> * * @return <code>true</code> if the receiver is empty, and <code>false</code> otherwise */public boolean isEmpty () {	return (width <= 0) || (height <= 0);}/** * Returns a string containing a concise, human-readable * description of the receiver. * * @return a string representation of the rectangle */public String toString () {	return "Rectangle {" + x + ", " + y + ", " + width + ", " + height + "}"; //$NON-NLS-1$//$NON-NLS-2$ //$NON-NLS-3$ //$NON-NLS-4$ //$NON-NLS-5$}/** * Returns a new rectangle which represents the union of * the receiver and the given rectangle. * <p> * The union of two rectangles is the smallest single rectangle * that completely covers both of the areas covered by the two * given rectangles. * </p> * * @param rect the rectangle to perform union with * @return the union of the receiver and the argument * * @exception IllegalArgumentException <ul> *    <li>ERROR_NULL_ARGUMENT - if the argument is null</li> * </ul> * * @see #add(Rectangle) */public Rectangle union (Rectangle rect) {	if (rect == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);	int left = x < rect.x ? x : rect.x;	int top = y < rect.y ? y : rect.y;	int lhs = x + width;	int rhs = rect.x + rect.width;	int right = lhs > rhs ? lhs : rhs;	lhs = y + height;	rhs = rect.y + rect.height;	int bottom = lhs > rhs ? lhs : rhs;	return new Rectangle (left, top, right - left, bottom - top);}}