org.eclipse.swt.graphics.RGBA.java Source code

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Here is the source code for org.eclipse.swt.graphics.RGBA.java

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/*******************************************************************************
 * Copyright (c) 2015, 2016 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.graphics;

import java.io.*;

import org.eclipse.swt.*;

/**
 * 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 Serializable {
    /**
     * the RGB component of the RGBA
     */
    public final 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 RGBA))
            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 << 24) | (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 + "}"; //$NON-NLS-1$//$NON-NLS-2$ //$NON-NLS-3$ //$NON-NLS-4$
    }

}