bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/graphics/RGBA.java

/*******************************************************************************
 * Copyright (c) 2015 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
 *******************************************************************************/
package org.eclipse.swt.graphics;

import org.eclipse.swt.*;
import org.eclipse.swt.internal.*;

/**
 * Instances of this class are descriptions of colors in
 * terms of the primary additive color model (red, green, blue
 * and alpha). A color may be described in terms of the relative
 * intensities of these three primary colors. The brightness
 * of each color is specified by a value in the range 0 to 255,
 * where 0 indicates no color (blackness) and 255 indicates
 * maximum intensity and for alpha 0 indicates transparent and
 * 255 indicates opaque.
 * <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 Color
 * @see <a href="http://www.eclipse.org/swt/snippets/#color">Color and RGB snippets</a>
 * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
 * @since 3.104
 */
public final class RGBA implements SerializableCompatibility {
	/**
	 * the RGB component of the RGBA
	 */
	public RGB rgb;
	
	/**
	 * the alpha component of the RGBA
	 */
	public int alpha;
	
	static final long serialVersionUID = 1049467103126495855L;
	
/**
 * Constructs an instance of this class with the given
 * red, green, blue and alpha values.
 *
 * @param red the red component of the new instance
 * @param green the green component of the new instance
 * @param blue the blue component of the new instance
 * @param alpha the alpha component of the new instance
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the red, green, blue or alpha argument is not between 0 and 255</li>
 * </ul>
 */
public RGBA(int red, int green, int blue, int alpha) {
	if ((alpha > 255) || (alpha < 0)) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
	this.rgb = new RGB (red, green, blue);
	this.alpha = alpha;
}

/**
* Constructs an instance of this class with the given
* hue, saturation, and brightness.
*
* @param hue the hue value for the HSBA color (from 0 to 360)
* @param saturation the saturation value for the HSBA color (from 0 to 1)
* @param brightness the brightness value for the HSBA color (from 0 to 1)
* @param alpha the alpha value for the HSBA color (from 0 to 255)
*
* @exception IllegalArgumentException <ul>
*    <li>ERROR_INVALID_ARGUMENT - if the hue is not between 0 and 360 or
*    the saturation or brightness is not between 0 and 1 or if the alpha
*    is not between 0 and 255</li>
* </ul>
* 
*/
public RGBA(float hue, float saturation, float brightness, float alpha) {
	if ((alpha > 255) || (alpha < 0)) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
	rgb = new RGB(hue, saturation, brightness);
	this.alpha = (int)(alpha + 0.5);
}

/**
 * Returns the hue, saturation, and brightness of the color.
 * 
 * @return color space values in float format:<ul>
 *             <li>hue (from 0 to 360)</li>
 *             <li>saturation (from 0 to 1)</li>
 *             <li>brightness (from 0 to 1)</li>
 *             <li>alpha (from 0 to 255)</li>
 *             </ul>
 * @see #RGBA(float, float, float, float)
 */
public float[] getHSBA() {	
	float[] hsb = rgb.getHSB();
	return new float[] {hsb[0], hsb[1], hsb[2], alpha};
}	

/**
 * 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 RGB)) return false;
	RGBA rgba = (RGBA)object;
	return (rgba.rgb.red == this.rgb.red) && (rgba.rgb.green == this.rgb.green) && (rgba.rgb.blue == this.rgb.blue)
			&& (rgba.alpha == this.alpha);
}

/**
 * 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 (alpha << 32) | (rgb.blue << 16) | (rgb.green << 8) | rgb.red;
}

/**
 * Returns a string containing a concise, human-readable
 * description of the receiver.
 *
 * @return a string representation of the <code>RGBA</code>
 */
@Override
public String toString() {
	return "RGBA {" + rgb.red + ", " + rgb.green + ", " + rgb.blue + ", " + alpha + "}"; //$NON-NLS-1$//$NON-NLS-2$ //$NON-NLS-3$ //$NON-NLS-4$
}

}