color.java

Hecl编程语言是一个高层次的脚本语言的Java实现。其用意是要小

/*
 * Copyright (C) 2005, 2006 data2c GmbH (www.data2c.com)
 *
 * Author: Wolfgang S. Kechel - [e-mail]
 *
 * J2ME version of java.awt.Color. 
 */
//#ifndef j2se

package org.awt;

/**
 * The <code>Color</code> class is used encapsulate colors in the default
 * sRGB color space or colors in arbitrary color spaces identified by a
 * {@link ColorSpace}.  Every color has an implicit alpha value of 1.0 or
 * an explicit one provided in the constructor.  The alpha value
 * defines the transparency of a color and can be represented by
 * a float value in the range 0.0&nbsp;-&nbsp;1.0 or 0&nbsp;-&nbsp;255.
 * An alpha value of 1.0 or 255 means that the color is completely
 * opaque and an alpha value of 0 or 0.0 means that the color is 
 * completely transparent.
 * When constructing a <code>Color</code> with an explicit alpha or
 * getting the color/alpha components of a <code>Color</code>, the color
 * components are never premultiplied by the alpha component.
 * <p>
 * The default color space for the Java 2D(tm) API is sRGB, a proposed
 * standard RGB color space.  For further information on sRGB,
 * see <A href="http://www.w3.org/pub/WWW/Graphics/Color/sRGB.html">
 * http://www.w3.org/pub/WWW/Graphics/Color/sRGB.html
 * </A>.
 * <p>
 */
public class Color implements Transparency /*Paint, java.io.Serializable*/ {
    
    /**
     * The color white.  In the default sRGB space.
     */
    public final static Color white = new Color(255, 255, 255);
    public final static Color WHITE = white;

    /**
     * The color light gray.  In the default sRGB space.
     */
    public final static Color lightGray = new Color(192, 192, 192);
    public final static Color LIGHT_GRAY = lightGray;

    /**
     * The color gray.  In the default sRGB space.
     */
    public final static Color gray = new Color(128, 128, 128);
    public final static Color GRAY = gray;

    /**
     * The color dark gray.  In the default sRGB space.
     */
    public final static Color darkGray = new Color(64, 64, 64);
    public final static Color DARK_GRAY = darkGray;

    /**
     * The color black.  In the default sRGB space.
     */
    public final static Color black = new Color(0, 0, 0);
    public final static Color BLACK = black;
    
    /**
     * The color red.  In the default sRGB space.
     */
    public final static Color red = new Color(255, 0, 0);
    public final static Color RED = red;

    /**
     * The color pink.  In the default sRGB space.
     */
    public final static Color pink = new Color(255, 175, 175);
    public final static Color PINK = pink;

    /**
     * The color orange.  In the default sRGB space.
     */
    public final static Color orange = new Color(255, 200, 0);
    public final static Color ORANGE = orange;

    /**
     * The color yellow.  In the default sRGB space.
     */
    public final static Color yellow = new Color(255, 255, 0);
    public final static Color YELLOW = yellow;

    /**
     * The color green.  In the default sRGB space.
     */
    public final static Color green = new Color(0, 255, 0);
    public final static Color GREEN = green;

    /**
     * The color magenta.  In the default sRGB space.
     */
    public final static Color magenta = new Color(255, 0, 255);
    public final static Color MAGENTA = magenta;

    /**
     * The color cyan.  In the default sRGB space.
     */
    public final static Color cyan = new Color(0, 255, 255);
    public final static Color CYAN = cyan;

    /**
     * The color blue.  In the default sRGB space.
     */
    public final static Color blue = new Color(0, 0, 255);
    public final static Color BLUE = blue;

    /**
     * The color value.
     * @serial
     * @see #getRGB
     */
    int value;

    /**
     * Checks the color integer components supplied for validity.
     * Throws an {@link IllegalArgumentException} if the value is out of
     * range.
     * @param r the Red component
     * @param g the Green component
     * @param b the Blue component
     **/
    private static void testColorValueRange(int r, int g, int b, int a) {
        boolean rangeError = false;
	String badComponentString = "";
	
	if ( a < 0 || a > 255) {
	    rangeError = true;
	    badComponentString = badComponentString + " Alpha";
	}
        if ( r < 0 || r > 255) {
	    rangeError = true;
	    badComponentString = badComponentString + " Red";
	}
	if ( g < 0 || g > 255) {
	    rangeError = true;
	    badComponentString = badComponentString + " Green";
	}
	if ( b < 0 || b > 255) {
	    rangeError = true;
	    badComponentString = badComponentString + " Blue";
	}
	if ( rangeError == true ) {
	throw new IllegalArgumentException("Color parameter outside of expected range:"
					   + badComponentString);
	}
    }


    /**
     * Creates an opaque sRGB color with the specified red, green, 
     * and blue values in the range (0 - 255).  
     * The actual color used in rendering depends
     * on finding the best match given the color space 
     * available for a given output device.  
     * Alpha is defaulted to 255.
     * @param r the red component
     * @param g the green component
     * @param b the blue component
     * @see #getRed
     * @see #getGreen
     * @see #getBlue
     * @see #getRGB
     */
    public Color(int r, int g, int b) {
        this(r, g, b, 255);
    }

    /**
     * Creates an sRGB color with the specified red, green, blue, and alpha
     * values in the range (0 - 255).
     * @param r the red component
     * @param g the green component
     * @param b the blue component
     * @param a the alpha component
     * @see #getRed
     * @see #getGreen
     * @see #getBlue
     * @see #getAlpha
     * @see #getRGB
     */
    public Color(int r, int g, int b, int a) {
        value = ((a & 0xFF) << 24) |
                ((r & 0xFF) << 16) |
                ((g & 0xFF) << 8)  |
                ((b & 0xFF) << 0);
	testColorValueRange(r,g,b,a);
    }

    /**
     * Creates an opaque sRGB color with the specified combined RGB value
     * consisting of the red component in bits 16-23, the green component
     * in bits 8-15, and the blue component in bits 0-7.  The actual color
     * used in rendering depends on finding the best match given the
     * color space available for a particular output device.  Alpha is
     * defaulted to 255.
     * @param rgb the combined RGB components
     * @see java.awt.image.ColorModel#getRGBdefault
     * @see #getRed
     * @see #getGreen
     * @see #getBlue
     * @see #getRGB
     */
    public Color(int rgb) {
        value = 0xff000000 | rgb;
    }

    /**
     * Creates an sRGB color with the specified combined RGBA value consisting
     * of the alpha component in bits 24-31, the red component in bits 16-23,
     * the green component in bits 8-15, and the blue component in bits 0-7.
     * If the <code>hasalpha</code> argument is <code>false</code>, alpha
     * is defaulted to 255.
     * @param rgba the combined RGBA components
     * @param hasalpha <code>true</code> if the alpha bits are valid;
     * <code>false</code> otherwise
     * @see java.awt.image.ColorModel#getRGBdefault
     * @see #getRed
     * @see #getGreen
     * @see #getBlue
     * @see #getAlpha
     * @see #getRGB
     */
    public Color(int rgba, boolean hasalpha) {
        if (hasalpha) {
            value = rgba;
        } else {
            value = 0xff000000 | rgba;
        }
    }


    /**
     * Returns the red component in the range 0-255 in the default sRGB
     * space.
     * @return the red component.
     * @see #getRGB
     */
    public int getRed() {
	return (getRGB() >> 16) & 0xFF;
    }

    /**
     * Returns the green component in the range 0-255 in the default sRGB
     * space.
     * @return the green component.
     * @see #getRGB
     */
    public int getGreen() {
	return (getRGB() >> 8) & 0xFF;
    }

    /**
     * Returns the blue component in the range 0-255 in the default sRGB
     * space.
     * @return the blue component.
     * @see #getRGB
     */
    public int getBlue() {
	return (getRGB() >> 0) & 0xFF;
    }

    /**
     * Returns the alpha component in the range 0-255.
     * @return the alpha component.
     * @see #getRGB
     */
    public int getAlpha() {
        return (getRGB() >> 24) & 0xff;
    }

    /**
     * Returns the RGB value representing the color in the default sRGB
     * {@link ColorModel}.
     * (Bits 24-31 are alpha, 16-23 are red, 8-15 are green, 0-7 are
     * blue).
     * @return the RGB value of the color in the default sRGB
     *         <code>ColorModel</code>.
     * @see java.awt.image.ColorModel#getRGBdefault
     * @see #getRed
     * @see #getGreen
     * @see #getBlue
     * @since JDK1.0
     */
    public int getRGB() {
	return value;
    }

    private static final double FACTOR = 0.7;