/*******************************************************************************

 * Copyright (c) 2000, 2007 IBM Corporation and others.

 * Portion Copyright (c) 2008 Nokia Corporation and/or its subsidiary(-ies).

 * 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

 *     Nokia Corporation - Qt implementation

 *******************************************************************************/

package org.eclipse.swt.graphics;

import org.eclipse.swt.SWT;

/**

 * Instances of this class manage the operating system resources that

 * implement SWT's RGB color model. To create a color you can either

 * specify the individual color components as integers in the range 

 * 0 to 255 or provide an instance of an <code>RGB</code>. 

 * <p>

 * Application code must explicitly invoke the <code>Color.dispose()</code> 

 * method to release the operating system resources managed by each instance

 * when those instances are no longer required.

 * </p>

 *

 * @see RGB

 * @see Device#getSystemColor

 */

public final class Color extends Object {

/**

 * the handle to the OS color resource 

 * (Warning: This field is platform dependent)

 * <p>

 * <b>IMPORTANT:</b> This field is <em>not</em> part of the SWT

 * public API. It is marked public only so that it can be shared

 * within the packages provided by SWT. It is not available on all

 * platforms and should never be accessed from application code.

 * </p>

 */

public int handle;

/**

 * the device where this resource was created

 */

Device device;

/**

 * Prevents uninitialized instances from being created outside the package.

 */

Color() {

}

/**	 

 * Constructs a new instance of this class given a device and the

 * desired red, green and blue values expressed as ints in the range

 * 0 to 255 (where 0 is black and 255 is full brightness). On limited

 * color devices, the color instance created by this call may not have

 * the same RGB values as the ones specified by the arguments. The

 * RGB values on the returned instance will be the color values of 

 * the operating system color.

 * <p>

 * You must dispose the color when it is no longer required. 

 * </p>

 *

 * @param device the device on which to allocate the color

 * @param red the amount of red in the color

 * @param green the amount of green in the color

 * @param blue the amount of blue in the color

 *

 * @exception IllegalArgumentException <ul>

 *    <li>ERROR_NULL_ARGUMENT - if device is null and there is no current device</li>

 *    <li>ERROR_INVALID_ARGUMENT - if the red, green or blue argument is not between 0 and 255</li>

 * </ul>

 *

 * @see #dispose

 */

public Color(Device device, int red, int green, int blue) {

    init(device, red, green, blue);

}

/**	 

 * Constructs a new instance of this class given a device and an

 * <code>RGB</code> describing the desired red, green and blue values.

 * On limited color devices, the color instance created by this call

 * may not have the same RGB values as the ones specified by the

 * argument. The RGB values on the returned instance will be the color

 * values of the operating system color.

 * <p>

 * You must dispose the color when it is no longer required. 

 * </p>

 *

 * @param device the device on which to allocate the color

 * @param rgb the RGB values of the desired color

 *

 * @exception IllegalArgumentException <ul>

 *    <li>ERROR_NULL_ARGUMENT - if device is null and there is no current device</li>

 *    <li>ERROR_NULL_ARGUMENT - if the rgb argument is null</li>

 *    <li>ERROR_INVALID_ARGUMENT - if the red, green or blue components of the argument are not between 0 and 255</li>

 * </ul>

 *

 * @see #dispose

 */

public Color(Device device, RGB rgb) {

    if (rgb == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);

    init(device, rgb.red, rgb.green, rgb.blue);

}

/**

 * Disposes of the operating system resources associated with

 * this resource. Applications must dispose of all resources

 * which they allocate.

 */

public void dispose() {

    if (device == null) return;

    if (device.isDisposed()) return;    

    device = null;

    handle = -1;

}

/**

 * 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 Color)) return false;

    Color color = (Color)object;

    if (isDisposed() || color.isDisposed()) return false;

    return device == color.device && (handle & 0xFFFFFF) == (color.handle & 0xFFFFFF);

}

/**

 * Returns the amount of blue in the color, from 0 to 255.

 *

 * @return the blue component of the color

 *

 * @exception SWTException <ul>

 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>

 * </ul>

 */

public int getBlue() {

    if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);

    return (handle & 0xFF0000) >> 16;

}

/**

 * Returns the amount of green in the color, from 0 to 255.

 *

 * @return the green component of the color

 *

 * @exception SWTException <ul>

 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>

 * </ul>

 */

public int getGreen() {

    if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);

    return (handle & 0xFF00) >> 8 ;

}

/**

 * Returns the amount of red in the color, from 0 to 255.

 *

 * @return the red component of the color

 *

 * @exception SWTException <ul>

 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>

 * </ul>

 */

public int getRed() {

    if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);

    return handle & 0xFF;

}

/**

 * Returns an <code>RGB</code> representing the receiver.

 *

 * @return the RGB for the color

 *

 * @exception SWTException <ul>

 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>

 * </ul>

 */

public RGB getRGB () {

    if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);

    return new RGB(handle & 0xFF, (handle & 0xFF00) >> 8, (handle & 0xFF0000) >> 16);

}

/**

 * 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

 */

public int hashCode() {

    if (isDisposed()) return 0;

    return handle;

}

/*

 * Invokes platform specific functionality to allocate a new color.

 */

void init(Device device, int red, int green, int blue) {

    if (device == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);

    this.device = device;

    if ((red > 255)   || (red < 0)   ||

        (green > 255) || (green < 0) ||

        (blue > 255)  || (blue < 0)) {

            SWT.error(SWT.ERROR_INVALID_ARGUMENT);		

    }

    handle = (red & 0xFF) | ((green & 0xFF) << 8) | ((blue & 0xFF) << 16);

    // Keep this after dealing with all exceptions!

}

/**

 * Returns <code>true</code> if the color has been disposed,

 * and <code>false</code> otherwise.

 * <p>

 * This method gets the dispose state for the color.

 * When a color has been disposed, it is an error to

 * invoke any other method using the color.

 *

 * @return <code>true</code> when the color is disposed and <code>false</code> otherwise

 */

public boolean isDisposed() {

    return handle == -1;

}

/**

 * Returns a string containing a concise, human-readable

 * description of the receiver.

 *

 * @return a string representation of the receiver

 */

public String toString () {

    if (isDisposed()) return "Color {*DISPOSED*}";

    return "Color {" + getRed() + ", " + getGreen() + ", " + getBlue() + "}";

}

/*

 * Invokes platform specific functionality to allocate a new color.

 */

static Color qt_new(Device device, int handle) {

    Color color = new Color();

    color.device = device;

    color.handle = handle; // Rgb value

    return color;

}

}