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SWT is an open source widget toolkit for Java designed to provide efficient, portable access to the user-interface facilities of the operating systems on which it is implemented.
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/*******************************************************************************
* Copyright (c) 2000, 2013 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 and
* blue). 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.
*
* 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.
*
*
* Application code does not need to explicitly release the
* resources managed by each instance when those instances are no longer
* required, and thus no dispose() method is provided.
*
*
* @see Color
* @see Color and RGB snippets
* @see Sample code and further information
*/
public final class RGB implements SerializableCompatibility {
/**
* the red component of the RGB
*/
public int red;
/**
* the green component of the RGB
*/
public int green;
/**
* the blue component of the RGB
*/
public int blue;
static final long serialVersionUID = 3258415023461249074L;
/**
* Constructs an instance of this class with the given
* red, green and blue 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
*
* @exception IllegalArgumentException
* - ERROR_INVALID_ARGUMENT - if the red, green or blue argument is not between 0 and 255
*
*/
public RGB(int red, int green, int blue) {
if ((red > 255) || (red < 0) ||
(green > 255) || (green < 0) ||
(blue > 255) || (blue < 0))
SWT.error(SWT.ERROR_INVALID_ARGUMENT);
this.red = red;
this.green = green;
this.blue = blue;
}
/**
* Constructs an instance of this class with the given
* hue, saturation, and brightness.
*
* @param hue the hue value for the HSB color (from 0 to 360)
* @param saturation the saturation value for the HSB color (from 0 to 1)
* @param brightness the brightness value for the HSB color (from 0 to 1)
*
* @exception IllegalArgumentException
* - ERROR_INVALID_ARGUMENT - if the hue is not between 0 and 360 or
* the saturation or brightness is not between 0 and 1
*
*
* @since 3.2
*/
public RGB(float hue, float saturation, float brightness) {
if (hue < 0 || hue > 360 || saturation < 0 || saturation > 1 ||
brightness < 0 || brightness > 1) {
SWT.error(SWT.ERROR_INVALID_ARGUMENT);
}
float r, g, b;
if (saturation == 0) {
r = g = b = brightness;
} else {
if (hue == 360) hue = 0;
hue /= 60;
int i = (int)hue;
float f = hue - i;
float p = brightness * (1 - saturation);
float q = brightness * (1 - saturation * f);
float t = brightness * (1 - saturation * (1 - f));
switch(i) {
case 0:
r = brightness;
g = t;
b = p;
break;
case 1:
r = q;
g = brightness;
b = p;
break;
case 2:
r = p;
g = brightness;
b = t;
break;
case 3:
r = p;
g = q;
b = brightness;
break;
case 4:
r = t;
g = p;
b = brightness;
break;
case 5:
default:
r = brightness;
g = p;
b = q;
break;
}
}
red = (int)(r * 255 + 0.5);
green = (int)(g * 255 + 0.5);
blue = (int)(b * 255 + 0.5);
}
/**
* Returns the hue, saturation, and brightness of the color.
*
* @return color space values in float format:
* - hue (from 0 to 360)
* - saturation (from 0 to 1)
* - brightness (from 0 to 1)
*
* @see #RGB(float, float, float)
*
* @since 3.2
*/
public float[] getHSB() {
float r = red / 255f;
float g = green / 255f;
float b = blue / 255f;
float max = Math.max(Math.max(r, g), b);
float min = Math.min(Math.min(r, g), b);
float delta = max - min;
float hue = 0;
float brightness = max;
float saturation = max == 0 ? 0 : (max - min) / max;
if (delta != 0) {
if (r == max) {
hue = (g - b) / delta;
} else {
if (g == max) {
hue = 2 + (b - r) / delta;
} else {
hue = 4 + (r - g) / delta;
}
}
hue *= 60;
if (hue < 0) hue += 360;
}
return new float[] {hue, saturation, brightness};
}
/**
* Compares the argument to the receiver, and returns true
* if they represent the same object using a class
* specific comparison.
*
* @param object the object to compare with this object
* @return true if the object is the same as this object and false otherwise
*
* @see #hashCode()
*/
public boolean equals(Object object) {
if (object == this) return true;
if (!(object instanceof RGB)) return false;
RGB rgb = (RGB)object;
return (rgb.red == this.red) && (rgb.green == this.green) && (rgb.blue == this.blue);
}
/**
* Returns an integer hash code for the receiver. Any two
* objects that return true when passed to
* equals must return the same value for this
* method.
*
* @return the receiver's hash
*
* @see #equals(Object)
*/
public int hashCode() {
return (blue << 16) | (green << 8) | red;
}
/**
* Returns a string containing a concise, human-readable
* description of the receiver.
*
* @return a string representation of the RGB
*/
public String toString() {
return "RGB {" + red + ", " + green + ", " + blue + "}"; //$NON-NLS-1$//$NON-NLS-2$ //$NON-NLS-3$ //$NON-NLS-4$
}
}