plugins/org.eclipse.emf.parsley.web.servlets/src/org/eclipse/swt/graphics/Rectangle.java

/*******************************************************************************
 * Copyright (c) 2015 RCP Vision (http://www.rcp-vision.com) 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:
 * Vincenzo Caselli - Initial contribution and API
 * 
 *******************************************************************************/
package org.eclipse.swt.graphics;

import org.eclipse.swt.SWT;
import org.eclipse.swt.internal.SerializableCompatibility;

/**
 * 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
 * @see <a href="http://www.eclipse.org/swt/">Sample code and further
 *      information</a>
 */

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;

	static final long serialVersionUID = 3256439218279428914L;

	/**
	 * 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()
	 */
	@Override
	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 that
	 * 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)
	 */
	@Override
	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
	 */
	@Override
	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);
	}

}