/*******************************************************************************
 * Copyright (c) 2000, 2008 IBM Corporation 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
 *     
 * Port to the D programming language:
 *     Jacob Carlborg <doob@me.com>
 *******************************************************************************/
module dwt.graphics.Rectangle;


import dwt.DWT;
import dwt.internal.SerializableCompatibility;

import tango.text.convert.Format;

import dwt.dwthelper.utils;
import dwt.graphics.Point;

/**
 * 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 : 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 const 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 this (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 is null) DWT.error(DWT.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 bool 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 bool contains (Point pt) {
    if (pt is null) DWT.error(DWT.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 int opEquals (Object object) {
    if (object is this) return true;
    if (!( null !is cast(Rectangle)object )) return false;
    Rectangle r = cast(Rectangle)object;
    return (r.x is this.x) && (r.y is this.y) && (r.width is this.width) && (r.height is this.height);
}

alias opEquals equals;

/**
 * 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)
 */
public hash_t toHash () {
    return x ^ y ^ width ^ height;
}

alias toHash hashCode;

/**
 * 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 is null) DWT.error(DWT.ERROR_NULL_ARGUMENT);
    if (this is 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 is null) DWT.error(DWT.ERROR_NULL_ARGUMENT);
    if (this is 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 bool 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 bool intersects (Rectangle rect) {
    if (rect is null) DWT.error(DWT.ERROR_NULL_ARGUMENT);
    return rect is 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 bool 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 Format( "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 unionn (Rectangle rect) {
    if (rect is null) DWT.error(DWT.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);
}

}