Anyone Know Anything About Color?

[X Abstract X]

Edit: read my second post in this thread for a better description of my question.

[programmerinprogress]

yeah, the general rule is, the lower the RGB values, the darker the colour.

I'm assuming you know how colours in computers work?, you have the 3 main 8-bit components Red, Green and Blue, as each component is 8 bits, it can represent different intensities of the colour from 0 to 255.

255,255,255 is the highest possible value, this gives you white, 0,0, 0 gives you black, 128,128,128 is half way and gives you grey, the basic rules of colours apply the same way as they do in real life, mixing red and blue will give you purple, and red and green will give you yellow.

The system is additive meaning the more colour you put in, the the colour more it changes (gets brighter)

I hope that helped a bit.

[Lord Pingas]

That sure helped me.

Great reference for beginners in programming!

[X Abstract X]

While that is a nice introduction for people who don't know that stuff, that's not really what I'm asking. It's my fault, I'm bad at explaining stuff because I tend to assume people can read my mind =P. I'm looking to know what method will be the most accurate at darkening/lightening colors.

For example, If I wanted to darken a color I have 2 choices.

1. Reduce each color component by an arbitrary value (say 30)
2. Reduce each color component by an arbitrary percentage of it's initial value (say 20%)

Edit: I'm using #2 because it seems to make more sense.

[wearymemory]

I like number 2's.

You can see how the brighter and darker methods of the java.awt.Color class work.
Color.java

Code: Select all

/*
 * @(#)Color.java	1.80 08/05/29
 *
 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package java.awt;

import java.io.*;
import java.lang.*;
import java.awt.image.ColorModel;
import java.awt.geom.AffineTransform;
import java.awt.geom.Rectangle2D;
import java.awt.color.ColorSpace;

/**
 * The <code>Color</code> class is used to 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>
 * @version 	10 Feb 1997
 * @author 	Sami Shaio
 * @author 	Arthur van Hoff
 * @see		ColorSpace
 * @see         AlphaComposite
 */
public class Color implements Paint, java.io.Serializable {
    
    /**
     * The color white.  In the default sRGB space.
     */
    public final static Color white     = new Color(255, 255, 255);

    /**
     * The color white.  In the default sRGB space.
     * @since 1.4
     */
    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);

    /**
     * The color light gray.  In the default sRGB space.
     * @since 1.4
     */
    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);

    /**
     * The color gray.  In the default sRGB space.
     * @since 1.4
     */
    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);

    /**
     * The color dark gray.  In the default sRGB space.
     * @since 1.4
     */
    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);
    
    /**
     * The color black.  In the default sRGB space.
     * @since 1.4
     */
    public final static Color BLACK = black;
    
    /**
     * The color red.  In the default sRGB space.
     */
    public final static Color red       = new Color(255, 0, 0);

    /**
     * The color red.  In the default sRGB space.
     * @since 1.4
     */
    public final static Color RED = red;

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

    /**
     * The color pink.  In the default sRGB space.
     * @since 1.4
     */
    public final static Color PINK = pink;

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

    /**
     * The color orange.  In the default sRGB space.
     * @since 1.4
     */
    public final static Color ORANGE = orange;

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

    /**
     * The color yellow.  In the default sRGB space.
     * @since 1.4
     */
    public final static Color YELLOW = yellow;

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

    /**
     * The color green.  In the default sRGB space.
     * @since 1.4
     */
    public final static Color GREEN = green;

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

    /**
     * The color magenta.  In the default sRGB space.
     * @since 1.4
     */
    public final static Color MAGENTA = magenta;

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

    /**
     * The color cyan.  In the default sRGB space.
     * @since 1.4
     */
    public final static Color CYAN = cyan;

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

    /**
     * The color blue.  In the default sRGB space.
     * @since 1.4
     */
    public final static Color BLUE = blue;

    /**
     * Private data.
     */
    transient private long pData;

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

    /**
     * The color value in the default sRGB <code>ColorSpace</code> as
     * <code>float</code> components (no alpha).
     * If <code>null</code> after object construction, this must be an
     * sRGB color constructed with 8-bit precision, so compute from the
     * <code>int</code> color value. 
     * @serial
     * @see #getRGBColorComponents
     * @see #getRGBComponents
     */
    private float frgbvalue[] = null;

    /**
     * The color value in the native <code>ColorSpace</code> as
     * <code>float</code> components (no alpha).
     * If <code>null</code> after object construction, this must be an
     * sRGB color constructed with 8-bit precision, so compute from the
     * <code>int</code> color value. 
     * @serial
     * @see #getRGBColorComponents
     * @see #getRGBComponents  
     */
    private float fvalue[] = null;

    /**
     * The alpha value as a <code>float</code> component.
     * If <code>frgbvalue</code> is <code>null</code>, this is not valid
     * data, so compute from the <code>int</code> color value.
     * @serial
     * @see #getRGBComponents
     * @see #getComponents
     */
    private float falpha = 0.0f;

    /**
     * The <code>ColorSpace</code>.  If <code>null</code>, then it's
     * default is sRGB.
     * @serial
     * @see #getColor
     * @see #getColorSpace
     * @see #getColorComponents
     */
    private ColorSpace cs = null;

    /*
     * JDK 1.1 serialVersionUID 
     */
     private static final long serialVersionUID = 118526816881161077L;

    /**
     * Initialize JNI field and method IDs
     */
    private static native void initIDs();

    static {
        /** 4112352 - Calling getDefaultToolkit()
         ** here can cause this class to be accessed before it is fully
         ** initialized. DON'T DO IT!!!
         **
         ** Toolkit.getDefaultToolkit();
         **/

        /* ensure that the necessary native libraries are loaded */
	Toolkit.loadLibraries();
        if (!GraphicsEnvironment.isHeadless()) {
            initIDs();
        }
    }

    /**
     * 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);
	}
    }

    /**
     * Checks the color <code>float</code> components supplied for
     * validity.
     * Throws an <code>IllegalArgumentException</code> 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(float r, float g, float b, float a) {
        boolean rangeError = false;
	String badComponentString = "";
	if ( a < 0.0 || a > 1.0) {
	    rangeError = true;
	    badComponentString = badComponentString + " Alpha";
	}
	if ( r < 0.0 || r > 1.0) {
	    rangeError = true;
	    badComponentString = badComponentString + " Red";
	}
	if ( g < 0.0 || g > 1.0) {
	    rangeError = true;
	    badComponentString = badComponentString + " Green";
	}
	if ( b < 0.0 || b > 1.0) {
	    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.
     *
     * @throws IllegalArgumentException if <code>r</code>, <code>g</code>
     *        or <code>b</code> are outside of the range
     *        0 to 255, inclusive
     * @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).
     *
     * @throws IllegalArgumentException if <code>r</code>, <code>g</code>,
     *        <code>b</code> or <code>a</code> are outside of the range
     *        0 to 255, inclusive
     * @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;
        }
    }

    /**
     * Creates an opaque sRGB color with the specified red, green, and blue
     * values in the range (0.0 - 1.0).  Alpha is defaulted to 1.0.  The
     * actual color used in rendering depends on finding the best
     * match given the color space available for a particular output
     * device.
     *
     * @throws IllegalArgumentException if <code>r</code>, <code>g</code>
     *        or <code>b</code> are outside of the range
     *        0.0 to 1.0, inclusive
     * @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(float r, float g, float b) {
        this( (int) (r*255+0.5), (int) (g*255+0.5), (int) (b*255+0.5));
        testColorValueRange(r,g,b,1.0f);
        frgbvalue = new float[3];
        frgbvalue[0] = r;
        frgbvalue[1] = g;
        frgbvalue[2] = b;
        falpha = 1.0f;
        fvalue = frgbvalue;
    }

    /**
     * Creates an sRGB color with the specified red, green, blue, and
     * alpha values in the range (0.0 - 1.0).  The actual color
     * used in rendering depends on finding the best match given the
     * color space available for a particular output device.
     * @throws IllegalArgumentException if <code>r</code>, <code>g</code>
     *        <code>b</code> or <code>a</code> are outside of the range
     *        0.0 to 1.0, inclusive
     * @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(float r, float g, float b, float a) {
        this((int)(r*255+0.5), (int)(g*255+0.5), (int)(b*255+0.5), (int)(a*255+0.5));
        frgbvalue = new float[3];
        frgbvalue[0] = r;
        frgbvalue[1] = g;
        frgbvalue[2] = b;
        falpha = a;
        fvalue = frgbvalue;
    }

    /**
     * Creates a color in the specified <code>ColorSpace</code>
     * with the color components specified in the <code>float</code>
     * array and the specified alpha.  The number of components is
     * determined by the type of the <code>ColorSpace</code>.  For 
     * example, RGB requires 3 components, but CMYK requires 4 
     * components.
     * @param cspace the <code>ColorSpace</code> to be used to
     *			interpret the components
     * @param components an arbitrary number of color components
     *                      that is compatible with the <code>ColorSpace</code>
     * @param alpha alpha value
     * @throws IllegalArgumentException if any of the values in the 
     *         <code>components</code> array or <code>alpha</code> is 
     *         outside of the range 0.0 to 1.0
     * @see #getComponents
     * @see #getColorComponents
     */
    public Color(ColorSpace cspace, float components[], float alpha) {
        boolean rangeError = false;
        String badComponentString = "";
        int n = cspace.getNumComponents();
        fvalue = new float[n];
        for (int i = 0; i < n; i++) {
            if (components[i] < 0.0 || components[i] > 1.0) {
                rangeError = true;
                badComponentString = badComponentString + "Component " + i
                                     + " ";
            } else {
                fvalue[i] = components[i];
            }
        }
        if (alpha < 0.0 || alpha > 1.0) {
            rangeError = true;
            badComponentString = badComponentString + "Alpha";
        } else {
            falpha = alpha;
        }
        if (rangeError) {
            throw new IllegalArgumentException(
                "Color parameter outside of expected range: " +
                badComponentString);
        }
        frgbvalue = cspace.toRGB(fvalue);
	cs = cspace;
        value = ((((int)(falpha*255)) & 0xFF) << 24) |
                ((((int)(frgbvalue[0]*255)) & 0xFF) << 16) |
                ((((int)(frgbvalue[1]*255)) & 0xFF) << 8)  |
                ((((int)(frgbvalue[2]*255)) & 0xFF) << 0);
    }

    /**
     * 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;

    /**
     * Creates a new <code>Color</code> that is a brighter version of this
     * <code>Color</code>.
     * <p>
     * This method applies an arbitrary scale factor to each of the three RGB 
     * components of this <code>Color</code> to create a brighter version
     * of this <code>Color</code>. Although <code>brighter</code> and
     * <code>darker</code> are inverse operations, the results of a
     * series of invocations of these two methods might be inconsistent
     * because of rounding errors. 
     * @return     a new <code>Color</code> object that is  
     *                 a brighter version of this <code>Color</code>.
     * @see        java.awt.Color#darker
     * @since      JDK1.0
     */
    public Color brighter() {
        int r = getRed();
        int g = getGreen();
        int b = getBlue();

        /* From 2D group:
         * 1. black.brighter() should return grey
         * 2. applying brighter to blue will always return blue, brighter
         * 3. non pure color (non zero rgb) will eventually return white
         */
        int i = (int)(1.0/(1.0-FACTOR));
        if ( r == 0 && g == 0 && b == 0) {
           return new Color(i, i, i);
        }
        if ( r > 0 && r < i ) r = i;
        if ( g > 0 && g < i ) g = i;
        if ( b > 0 && b < i ) b = i;

        return new Color(Math.min((int)(r/FACTOR), 255),
                         Math.min((int)(g/FACTOR), 255),
                         Math.min((int)(b/FACTOR), 255));
    }

    /**
     * Creates a new <code>Color</code> that is a darker version of this
     * <code>Color</code>.
     * <p>
     * This method applies an arbitrary scale factor to each of the three RGB 
     * components of this <code>Color</code> to create a darker version of
     * this <code>Color</code>.  Although <code>brighter</code> and
     * <code>darker</code> are inverse operations, the results of a series 
     * of invocations of these two methods might be inconsistent because
     * of rounding errors. 
     * @return  a new <code>Color</code> object that is 
     *                    a darker version of this <code>Color</code>.
     * @see        java.awt.Color#brighter
     * @since      JDK1.0
     */
    public Color darker() {
	return new Color(Math.max((int)(getRed()  *FACTOR), 0), 
			 Math.max((int)(getGreen()*FACTOR), 0),
			 Math.max((int)(getBlue() *FACTOR), 0));
    }

    /**
     * Computes the hash code for this <code>Color</code>.
     * @return     a hash code value for this object.
     * @since      JDK1.0
     */
    public int hashCode() {
	return value;
    }

    /**
     * Determines whether another object is equal to this 
     * <code>Color</code>.
     * <p>
     * The result is <code>true</code> if and only if the argument is not 
     * <code>null</code> and is a <code>Color</code> object that has the same 
     * red, green, blue, and alpha values as this object. 
     * @param       obj   the object to test for equality with this
     *				<code>Color</code>
     * @return      <code>true</code> if the objects are the same; 
     *                             <code>false</code> otherwise.
     * @since   JDK1.0
     */
    public boolean equals(Object obj) {
        return obj instanceof Color && ((Color)obj).getRGB() == this.getRGB();
    }

    /**
     * Returns a string representation of this <code>Color</code>. This
     * method is intended to be used only for debugging purposes.  The 
     * content and format of the returned string might vary between 
     * implementations. The returned string might be empty but cannot 
     * be <code>null</code>.
     * 
     * @return  a string representation of this <code>Color</code>.
     */
    public String toString() {
        return getClass().getName() + "[r=" + getRed() + ",g=" + getGreen() + ",b=" + getBlue() + "]";
    }

    /**
     * Converts a <code>String</code> to an integer and returns the 
     * specified opaque <code>Color</code>. This method handles string
     * formats that are used to represent octal and hexidecimal numbers.
     * @param      nm a <code>String</code> that represents 
     *                            an opaque color as a 24-bit integer
     * @return     the new <code>Color</code> object.
     * @see        java.lang.Integer#decode
     * @exception  NumberFormatException  if the specified string cannot
     *                      be interpreted as a decimal, 
     *                      octal, or hexidecimal integer.
     * @since      JDK1.1
     */
    public static Color decode(String nm) throws NumberFormatException {
	Integer intval = Integer.decode(nm);
	int i = intval.intValue();
	return new Color((i >> 16) & 0xFF, (i >> 8) & 0xFF, i & 0xFF);
    }

    /**
     * Finds a color in the system properties. 
     * <p>
     * The argument is treated as the name of a system property to 
     * be obtained. The string value of this property is then interpreted 
     * as an integer which is then converted to a <code>Color</code>
     * object. 
     * <p>
     * If the specified property is not found or could not be parsed as 
     * an integer then <code>null</code> is returned. 
     * @param    nm the name of the color property
     * @return   the <code>Color</code> converted from the system 
     * 		property.
     * @see      java.lang.System#getProperty(java.lang.String)
     * @see      java.lang.Integer#getInteger(java.lang.String)
     * @see      java.awt.Color#Color(int)
     * @since    JDK1.0
     */
    public static Color getColor(String nm) {
	return getColor(nm, null);
    }

    /**
     * Finds a color in the system properties. 
     * <p>
     * The first argument is treated as the name of a system property to 
     * be obtained. The string value of this property is then interpreted 
     * as an integer which is then converted to a <code>Color</code>
     * object. 
     * <p>
     * If the specified property is not found or cannot be parsed as 
     * an integer then the <code>Color</code> specified by the second
     * argument is returned instead. 
     * @param    nm the name of the color property
     * @param    v    the default <code>Color</code>
     * @return   the <code>Color</code> converted from the system
     *		property, or the specified <code>Color</code>.
     * @see      java.lang.System#getProperty(java.lang.String)
     * @see      java.lang.Integer#getInteger(java.lang.String)
     * @see      java.awt.Color#Color(int)
     * @since    JDK1.0
     */
    public static Color getColor(String nm, Color v) {
	Integer intval = Integer.getInteger(nm);
	if (intval == null) {
	    return v;
	}
	int i = intval.intValue();
	return new Color((i >> 16) & 0xFF, (i >> 8) & 0xFF, i & 0xFF);
    }

    /**
     * Finds a color in the system properties. 
     * <p>
     * The first argument is treated as the name of a system property to 
     * be obtained. The string value of this property is then interpreted 
     * as an integer which is then converted to a <code>Color</code>
     * object. 
     * <p>
     * If the specified property is not found or could not be parsed as 
     * an integer then the integer value <code>v</code> is used instead, 
     * and is converted to a <code>Color</code> object.
     * @param    nm  the name of the color property
     * @param    v   the default color value, as an integer
     * @return   the <code>Color</code> converted from the system
     *		property or the <code>Color</code> converted from
     *		the specified integer.
     * @see      java.lang.System#getProperty(java.lang.String)
     * @see      java.lang.Integer#getInteger(java.lang.String)
     * @see      java.awt.Color#Color(int)
     * @since    JDK1.0
     */
    public static Color getColor(String nm, int v) {
	Integer intval = Integer.getInteger(nm);
	int i = (intval != null) ? intval.intValue() : v;
	return new Color((i >> 16) & 0xFF, (i >> 8) & 0xFF, (i >> 0) & 0xFF);
    }

    /**
     * Converts the components of a color, as specified by the HSB 
     * model, to an equivalent set of values for the default RGB model. 
     * <p>
     * The <code>saturation</code> and <code>brightness</code> components
     * should be floating-point values between zero and one
     * (numbers in the range 0.0-1.0).  The <code>hue</code> component
     * can be any floating-point number.  The floor of this number is
     * subtracted from it to create a fraction between 0 and 1.  This
     * fractional number is then multiplied by 360 to produce the hue
     * angle in the HSB color model.
     * <p>
     * The integer that is returned by <code>HSBtoRGB</code> encodes the 
     * value of a color in bits 0-23 of an integer value that is the same 
     * format used by the method {@link #getRGB() <code>getRGB</code>}.
     * This integer can be supplied as an argument to the
     * <code>Color</code> constructor that takes a single integer argument. 
     * @param     hue   the hue component of the color
     * @param     saturation   the saturation of the color
     * @param     brightness   the brightness of the color
     * @return    the RGB value of the color with the indicated hue, 
     *                            saturation, and brightness.
     * @see       java.awt.Color#getRGB()
     * @see       java.awt.Color#Color(int)
     * @see       java.awt.image.ColorModel#getRGBdefault()
     * @since     JDK1.0
     */
    public static int HSBtoRGB(float hue, float saturation, float brightness) {
	int r = 0, g = 0, b = 0;
    	if (saturation == 0) {
	    r = g = b = (int) (brightness * 255.0f + 0.5f);
	} else {
	    float h = (hue - (float)Math.floor(hue)) * 6.0f;
	    float f = h - (float)java.lang.Math.floor(h);
	    float p = brightness * (1.0f - saturation);
	    float q = brightness * (1.0f - saturation * f);
	    float t = brightness * (1.0f - (saturation * (1.0f - f)));
	    switch ((int) h) {
	    case 0:
		r = (int) (brightness * 255.0f + 0.5f);
		g = (int) (t * 255.0f + 0.5f);
		b = (int) (p * 255.0f + 0.5f);
		break;
	    case 1:
		r = (int) (q * 255.0f + 0.5f);
		g = (int) (brightness * 255.0f + 0.5f);
		b = (int) (p * 255.0f + 0.5f);
		break;
	    case 2:
		r = (int) (p * 255.0f + 0.5f);
		g = (int) (brightness * 255.0f + 0.5f);
		b = (int) (t * 255.0f + 0.5f);
		break;
	    case 3:
		r = (int) (p * 255.0f + 0.5f);
		g = (int) (q * 255.0f + 0.5f);
		b = (int) (brightness * 255.0f + 0.5f);
		break;
	    case 4:
		r = (int) (t * 255.0f + 0.5f);
		g = (int) (p * 255.0f + 0.5f);
		b = (int) (brightness * 255.0f + 0.5f);
		break;
	    case 5:
		r = (int) (brightness * 255.0f + 0.5f);
		g = (int) (p * 255.0f + 0.5f);
		b = (int) (q * 255.0f + 0.5f);
		break;
	    }
	}
	return 0xff000000 | (r << 16) | (g << 8) | (b << 0);
    }

    /**
     * Converts the components of a color, as specified by the default RGB 
     * model, to an equivalent set of values for hue, saturation, and 
     * brightness that are the three components of the HSB model. 
     * <p>
     * If the <code>hsbvals</code> argument is <code>null</code>, then a 
     * new array is allocated to return the result. Otherwise, the method 
     * returns the array <code>hsbvals</code>, with the values put into 
     * that array. 
     * @param     r   the red component of the color
     * @param     g   the green component of the color
     * @param     b   the blue component of the color
     * @param     hsbvals  the array used to return the 
     *                     three HSB values, or <code>null</code>
     * @return    an array of three elements containing the hue, saturation, 
     *                     and brightness (in that order), of the color with 
     *                     the indicated red, green, and blue components.
     * @see       java.awt.Color#getRGB()
     * @see       java.awt.Color#Color(int)
     * @see       java.awt.image.ColorModel#getRGBdefault()
     * @since     JDK1.0
     */
    public static float[] RGBtoHSB(int r, int g, int b, float[] hsbvals) {
	float hue, saturation, brightness;
	if (hsbvals == null) {
	    hsbvals = new float[3];
	}
    	int cmax = (r > g) ? r : g;
	if (b > cmax) cmax = b;
	int cmin = (r < g) ? r : g;
	if (b < cmin) cmin = b;

	brightness = ((float) cmax) / 255.0f;
	if (cmax != 0)
	    saturation = ((float) (cmax - cmin)) / ((float) cmax);
	else
	    saturation = 0;
	if (saturation == 0)
	    hue = 0;
	else {
	    float redc = ((float) (cmax - r)) / ((float) (cmax - cmin));
	    float greenc = ((float) (cmax - g)) / ((float) (cmax - cmin));
	    float bluec = ((float) (cmax - b)) / ((float) (cmax - cmin));
	    if (r == cmax)
		hue = bluec - greenc;
	    else if (g == cmax)
	        hue = 2.0f + redc - bluec;
            else
		hue = 4.0f + greenc - redc;
	    hue = hue / 6.0f;
	    if (hue < 0)
		hue = hue + 1.0f;
	}
	hsbvals[0] = hue;
	hsbvals[1] = saturation;
	hsbvals[2] = brightness;
	return hsbvals;
    }

    /**
     * Creates a <code>Color</code> object based on the specified values 
     * for the HSB color model. 
     * <p>
     * The <code>s</code> and <code>b</code> components should be
     * floating-point values between zero and one 
     * (numbers in the range 0.0-1.0).  The <code>h</code> component 
     * can be any floating-point number.  The floor of this number is 
     * subtracted from it to create a fraction between 0 and 1.  This 
     * fractional number is then multiplied by 360 to produce the hue
     * angle in the HSB color model.
     * @param  h   the hue component
     * @param  s   the saturation of the color
     * @param  b   the brightness of the color
     * @return  a <code>Color</code> object with the specified hue, 
     *                                 saturation, and brightness.
     * @since   JDK1.0
     */
    public static Color getHSBColor(float h, float s, float b) {
	return new Color(HSBtoRGB(h, s, b));
    }

    /**
     * Returns a <code>float</code> array containing the color and alpha
     * components of the <code>Color</code>, as represented in the default
     * sRGB color space.
     * If <code>compArray</code> is <code>null</code>, an array of length
     * 4 is created for the return value.  Otherwise, 
     * <code>compArray</code> must have length 4 or greater,
     * and it is filled in with the components and returned.
     * @param compArray an array that this method fills with 
     *			color and alpha components and returns
     * @return the RGBA components in a <code>float</code> array.
     */
    public float[] getRGBComponents(float[] compArray) {
        float[] f;
        if (compArray == null) {
            f = new float[4];
        } else {
            f = compArray;
        }
        if (frgbvalue == null) {
            f[0] = ((float)getRed())/255f;
            f[1] = ((float)getGreen())/255f;
            f[2] = ((float)getBlue())/255f;
            f[3] = ((float)getAlpha())/255f;
        } else {
            f[0] = frgbvalue[0];
            f[1] = frgbvalue[1];
            f[2] = frgbvalue[2];
            f[3] = falpha;
        }
        return f;
    }

    /**
     * Returns a <code>float</code> array containing only the color
     * components of the <code>Color</code>, in the default sRGB color
     * space.  If <code>compArray</code> is <code>null</code>, an array of
     * length 3 is created for the return value.  Otherwise,
     * <code>compArray</code> must have length 3 or greater, and it is
     * filled in with the components and returned.
     * @param compArray an array that this method fills with color 
     *		components and returns
     * @return the RGB components in a <code>float</code> array.
     */
    public float[] getRGBColorComponents(float[] compArray) {
        float[] f;
        if (compArray == null) {
            f = new float[3];
        } else {
            f = compArray;
        }
        if (frgbvalue == null) {
            f[0] = ((float)getRed())/255f;
            f[1] = ((float)getGreen())/255f;
            f[2] = ((float)getBlue())/255f;
        } else {
            f[0] = frgbvalue[0];
            f[1] = frgbvalue[1];
            f[2] = frgbvalue[2];
        }
        return f;
    }

    /**
     * Returns a <code>float</code> array containing the color and alpha
     * components of the <code>Color</code>, in the
     * <code>ColorSpace</code> of the <code>Color</code>.
     * If <code>compArray</code> is <code>null</code>, an array with
     * length equal to the number of components in the associated
     * <code>ColorSpace</code> plus one is created for
     * the return value.  Otherwise, <code>compArray</code> must have at
     * least this length and it is filled in with the components and
     * returned.
     * @param compArray an array that this method fills with the color and
     *		alpha components of this <code>Color</code> in its
     *		<code>ColorSpace</code> and returns
     * @return the color and alpha components in a <code>float</code> 
     * 		array.
     */
    public float[] getComponents(float[] compArray) {
        if (fvalue == null)
            return getRGBComponents(compArray);
        float[] f;
        int n = fvalue.length;
        if (compArray == null) {
            f = new float[n + 1];
        } else {
            f = compArray;
        }
        for (int i = 0; i < n; i++) {
            f[i] = fvalue[i];
        }
        f[n] = falpha;
        return f;
    }

    /**
     * Returns a <code>float</code> array containing only the color
     * components of the <code>Color</code>, in the
     * <code>ColorSpace</code> of the <code>Color</code>.
     * If <code>compArray</code> is <code>null</code>, an array with
     * length equal to the number of components in the associated
     * <code>ColorSpace</code> is created for
     * the return value.  Otherwise, <code>compArray</code> must have at
     * least this length and it is filled in with the components and
     * returned.
     * @param compArray an array that this method fills with the color
     *		components of this <code>Color</code> in its
     *		<code>ColorSpace</code> and returns
     * @return the color components in a <code>float</code> array.
     */
    public float[] getColorComponents(float[] compArray) {
        if (fvalue == null)
            return getRGBColorComponents(compArray);
        float[] f;
        int n = fvalue.length;
        if (compArray == null) {
            f = new float[n];
        } else {
            f = compArray;
        }
        for (int i = 0; i < n; i++) {
            f[i] = fvalue[i];
        }
        return f;
    }

    /**
     * Returns a <code>float</code> array containing the color and alpha
     * components of the <code>Color</code>, in the 
     * <code>ColorSpace</code> specified by the <code>cspace</code> 
     * parameter.  If <code>compArray</code> is <code>null</code>, an
     * array with length equal to the number of components in 
     * <code>cspace</code> plus one is created for the return value.
     * Otherwise, <code>compArray</code> must have at least this
     * length, and it is filled in with the components and returned.
     * @param cspace a specified <code>ColorSpace</code>
     * @param compArray an array that this method fills with the
     *		color and alpha components of this <code>Color</code> in
     *		the specified <code>ColorSpace</code> and returns
     * @return the color and alpha components in a <code>float</code> 
     * 		array.
     */
    public float[] getComponents(ColorSpace cspace, float[] compArray) {
        if (cs == null) {
            cs = ColorSpace.getInstance(ColorSpace.CS_sRGB);
        }
        float f[];
        if (fvalue == null) {
            f = new float[3];
            f[0] = ((float)getRed())/255f;
            f[1] = ((float)getGreen())/255f;
            f[2] = ((float)getBlue())/255f;
        } else {
            f = fvalue;
        }
        float tmp[] = cs.toCIEXYZ(f);
        float tmpout[] = cspace.fromCIEXYZ(tmp);
        if (compArray == null) {
            compArray = new float[tmpout.length + 1];
        }
        for (int i = 0 ; i < tmpout.length ; i++) {
            compArray[i] = tmpout[i];
        }
        if (fvalue == null) {
            compArray[tmpout.length] = ((float)getAlpha())/255f;
        } else {
            compArray[tmpout.length] = falpha;
        }
        return compArray;
    }

    /**
     * Returns a <code>float</code> array containing only the color
     * components of the <code>Color</code> in the 
     * <code>ColorSpace</code> specified by the <code>cspace</code> 
     * parameter. If <code>compArray</code> is <code>null</code>, an array
     * with length equal to the number of components in 
     * <code>cspace</code> is created for the return value.  Otherwise,
     * <code>compArray</code> must have at least this length, and it is
     * filled in with the components and returned.
     * @param cspace a specified <code>ColorSpace</code>
     * @param compArray an array that this method fills with the color
     *		components of this <code>Color</code> in the specified
     * 		<code>ColorSpace</code>
     * @return the color components in a <code>float</code> array.
     */
    public float[] getColorComponents(ColorSpace cspace, float[] compArray) {
        if (cs == null) {
            cs = ColorSpace.getInstance(ColorSpace.CS_sRGB);
        }
        float f[];
        if (fvalue == null) {
            f = new float[3];
            f[0] = ((float)getRed())/255f;
            f[1] = ((float)getGreen())/255f;
            f[2] = ((float)getBlue())/255f;
        } else {
            f = fvalue;
        }
        float tmp[] = cs.toCIEXYZ(f);
        float tmpout[] = cspace.fromCIEXYZ(tmp);
        if (compArray == null) {
            return tmpout;
        }
        for (int i = 0 ; i < tmpout.length ; i++) {
            compArray[i] = tmpout[i];
        }
        return compArray;
    }

    /**
     * Returns the <code>ColorSpace</code> of this <code>Color</code>.
     * @return this <code>Color</code> object's <code>ColorSpace</code>.
     */
    public ColorSpace getColorSpace() {
        if (cs == null) {
            cs = ColorSpace.getInstance(ColorSpace.CS_sRGB);
        }
        return cs;
    }

    // REMIND: this should really be a Ref!
    /**
     * The paint context used to generate a solid color pattern.
     * @see createContext()
     */
    transient private PaintContext theContext;

    /**
     * Creates and returns a {@link PaintContext} used to generate a solid
     * color pattern.  This enables a <code>Color</code> object to be used
     * as an argument to any method requiring an object implementing the
     * {@link Paint} interface.
     * The same <code>PaintContext</code> is returned, regardless of
     * whether or not <code>r</code>, <code>r2d</code>,
     * <code>xform</code>, or <code>hints</code> are <code>null</code>.
     * @param cm the specified <code>ColorModel</code>
     * @param r the specified {@link Rectangle}
     * @param r2d the specified {@link Rectangle2D}
     * @param xform the specified {@link AffineTransform}
     * @param hints the specified {@link RenderingHints}
     * @return a <code>PaintContext</code> that is used to generate a
     *		solid color pattern.
     * @see Paint
     * @see PaintContext
     * @see Graphics2D#setPaint
     */
    public synchronized PaintContext createContext(ColorModel cm, Rectangle r,
						   Rectangle2D r2d,
						   AffineTransform xform,
                                                   RenderingHints hints) {
	PaintContext pc = theContext;
	if (pc == null || ((ColorPaintContext)pc).color != getRGB()) {
	    pc = new ColorPaintContext(getRGB(), cm);
	    theContext = pc;
	}
	return pc;
    }

    /**
     * Returns the transparency mode for this <code>Color</code>.  This is
     * required to implement the <code>Paint</code> interface.
     * @return this <code>Color</code> object's transparency mode.
     * @see Paint
     * @see Transparency
     * @see #createContext
     */
    public int getTransparency() {
        int alpha = getAlpha();
        if (alpha == 0xff) {
            return Transparency.OPAQUE;
        }
        else if (alpha == 0) {
            return Transparency.BITMASK;
        }
        else {
            return Transparency.TRANSLUCENT;
        }
    }

}

[Live-Dimension]

I'm looking to know what method will be the most accurate at darkening/lightening colors.

Color theory mate. Look it up. You don't just make a color have more black. Yes, this does darken them, but no its not accurate. Color changes as they get lighter/go darker.

[wearymemory]

I'm looking to know what method will be the most accurate at darkening/lightening colors.

Color theory mate. Look it up. You don't just make a color have more black. Yes, this does darken them, but no its not accurate. Color changes as they get lighter/go darker.

Theoretically, when using a scale factor like the one used in the code above, the rules are:
1. A brighter black should be gray.
2. A brighter blue will always be blue, brighter ([r=0,g=0,b=255] being the brightest blue). The same can be said for yellow, red, green, etc.
3. Non pure color (non zero rgb), brightened, will eventually return white.
Darkness is the inverse (excluding rule 2: brightening a color that has been darkened to black, will only result in a brighter black).
The system can be inconsistent due to rounding errors.