/*******************************************************************************
* 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
*******************************************************************************/
package org.eclipse.swt.graphics;
import org.eclipse.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 RGB.
*
* Application code must explicitly invoke the Color.dispose()
* method to release the operating system resources managed by each instance
* when those instances are no longer required.
*
*
* @see RGB
* @see Device#getSystemColor
* @see Color and RGB snippets
* @see SWT Example: PaintExample
* @see Sample code and further information
*/
public final class Color extends Resource {
/**
* the handle to the OS color resource
* (Warning: This field is platform dependent)
*
* IMPORTANT: This field is not 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.
*
*
* @noreference This field is not intended to be referenced by clients.
*/
public float /*double*/ [] handle;
Color(Device device) {
super(device);
}
/**
* 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.
*
* You must dispose the color when it is no longer required.
*
*
* @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
* - ERROR_NULL_ARGUMENT - if device is null and there is no current device
* - ERROR_INVALID_ARGUMENT - if the red, green or blue argument is not between 0 and 255
*
*
* @see #dispose
*/
public Color(Device device, int red, int green, int blue) {
super(device);
init(red, green, blue);
init();
}
/**
* Constructs a new instance of this class given a device and an
* RGB 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.
*
* You must dispose the color when it is no longer required.
*
*
* @param device the device on which to allocate the color
* @param rgb the RGB values of the desired color
*
* @exception IllegalArgumentException
* - ERROR_NULL_ARGUMENT - if device is null and there is no current device
* - ERROR_NULL_ARGUMENT - if the rgb argument is null
* - ERROR_INVALID_ARGUMENT - if the red, green or blue components of the argument are not between 0 and 255
*
*
* @see #dispose
*/
public Color(Device device, RGB rgb) {
super(device);
if (rgb == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
init(rgb.red, rgb.green, rgb.blue);
init();
}
void destroy() {
handle = null;
}
/**
* 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 Color)) return false;
Color color = (Color)object;
float /*double*/ [] rgbColor = color.handle;
if (handle == rgbColor) return true;
return device == color.device &&
(int)(handle[0] * 255) == (int)(rgbColor[0] * 255) &&
(int)(handle[1] * 255) == (int)(rgbColor[1] * 255) &&
(int)(handle[2] * 255) == (int)(rgbColor[2] * 255);
}
/**
* Returns the amount of blue in the color, from 0 to 255.
*
* @return the blue component of the color
*
* @exception SWTException
* - ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed
*
*/
public int getBlue() {
if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
return (int)(handle[2] * 255);
}
/**
* Returns the amount of green in the color, from 0 to 255.
*
* @return the green component of the color
*
* @exception SWTException
* - ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed
*
*/
public int getGreen() {
if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
return (int)(handle[1] * 255);
}
/**
* Returns the amount of red in the color, from 0 to 255.
*
* @return the red component of the color
*
* @exception SWTException
* - ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed
*
*/
public int getRed() {
if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
return (int)(handle[0] * 255);
}
/**
* 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
*/
public int hashCode() {
if (isDisposed()) return 0;
return (int)(handle[0] * 255) ^ (int)(handle[1] * 255) ^ (int)(handle[2] * 255);
}
/**
* Returns an RGB representing the receiver.
*
* @return the RGB for the color
*
* @exception SWTException
* - ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed
*
*/
public RGB getRGB () {
if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
return new RGB(getRed(), getGreen(), getBlue());
}
/**
* Invokes platform specific functionality to allocate a new color.
*
* IMPORTANT: This method is not part of the public
* API for Color. 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 called from
* application code.
*
*
* @param device the device on which to allocate the color
* @param handle the handle for the color
*
* @noreference This method is not intended to be referenced by clients.
*/
public static Color cocoa_new(Device device, float /*double*/ [] rgbColor) {
Color color = new Color(device);
color.handle = rgbColor;
return color;
}
void init(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);
}
float /*double*/ [] rgbColor = new float /*double*/ [4];
rgbColor[0] = red / 255f;
rgbColor[1] = green / 255f;
rgbColor[2] = blue / 255f;
rgbColor[3] = 1;
handle = rgbColor;
}
/**
* Returns true if the color has been disposed,
* and false otherwise.
*
* This method gets the dispose state for the color.
* When a color has been disposed, it is an error to
* invoke any other method (except {@link #dispose()}) using the color.
*
* @return true when the color is disposed and false otherwise
*/
public boolean isDisposed() {
return handle == null;
}
/**
* 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() + "}";
}
}