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Color.java
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/*
* @(#)Color.java 1.34 98/07/01
*
* Copyright 1995-1998 by Sun Microsystems, Inc.,
* 901 San Antonio Road, Palo Alto, California, 94303, U.S.A.
* All rights reserved.
*
* This software is the confidential and proprietary information
* of Sun Microsystems, Inc. ("Confidential Information"). You
* shall not disclose such Confidential Information and shall use
* it only in accordance with the terms of the license agreement
* you entered into with Sun.
*/
package java.awt;
import java.io.*;
import java.lang.*;
/**
* This class encapsulates colors using the RGB format. In RGB
* format, the red, blue, and green components of a color are each
* represented by an integer in the range 0-255. The value 0
* indicates no contribution from this primary color. The value 255
* indicates the maximum intensity of this color component.
* <p>
* Although the <code>Color</code> class is based on the
* three-component RGB model, the class provides a set of convenience
* methods for converting between RGB and HSB colors. For a
* definition of the RGB and HSB color models, see Foley, van Dam,
* Feiner, and Hughes, <cite>Computer Graphics: Principles
* and Practice</cite>.
*
* @version 1.34, 07/01/98
* @author Sami Shaio
* @author Arthur van Hoff
* @since JDK1.0
*/
public class Color implements java.io.Serializable {
/**
* The color white.
*/
public final static Color white = new Color(255, 255, 255);
/**
* The color light gray.
*/
public final static Color lightGray = new Color(192, 192, 192);
/**
* The color gray.
*/
public final static Color gray = new Color(128, 128, 128);
/**
* The color dark gray.
*/
public final static Color darkGray = new Color(64, 64, 64);
/**
* The color black.
*/
public final static Color black = new Color(0, 0, 0);
/**
* The color red.
*/
public final static Color red = new Color(255, 0, 0);
/**
* The color pink.
*/
public final static Color pink = new Color(255, 175, 175);
/**
* The color orange.
*/
public final static Color orange = new Color(255, 200, 0);
/**
* The color yellow.
*/
public final static Color yellow = new Color(255, 255, 0);
/**
* The color green.
*/
public final static Color green = new Color(0, 255, 0);
/**
* The color magenta.
*/
public final static Color magenta = new Color(255, 0, 255);
/**
* The color cyan.
*/
public final static Color cyan = new Color(0, 255, 255);
/**
* The color blue.
*/
public final static Color blue = new Color(0, 0, 255);
/**
* Private data.
*/
transient private int pData;
/**
* The color value.
*/
int value;
/*
* JDK 1.1 serialVersionUID
*/
private static final long serialVersionUID = 118526816881161077L;
/**
* Checks the color integer components supplied for validity.
* Throws an 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) {
boolean rangeError = false;
String badComponentString = "";
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 float components supplied for validity.
* Throws an 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(float r, float g, float b) {
boolean rangeError = false;
String badComponentString = "";
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 a color with the specified red, green, and blue
* components. The three arguments must each be in the range
* 0-255.
* <p>
* The actual color used in rendering depends on finding the best
* match given the color space available for a given output device.
* @param r the red component.
* @param g the green component.
* @param b the blue component.
* @see java.awt.Color#getRed.
* @see java.awt.Color#getGreen.
* @see java.awt.Color#getBlue.
* @see java.awt.Color#getRGB.
* @since JDK1.0
*/
public Color(int r, int g, int b) {
this(((r & 0xFF) << 16) | ((g & 0xFF) << 8) | ((b & 0xFF) << 0));
testColorValueRange(r,g,b);
}
/**
* Creates a color with the specified RGB value, where the red
* component is in bits 16-23 of the argument, the green
* component is in bits 8-15 of the argument, and the blue
* component is in bits 0-7. The value zero indicates no
* contribution from the primary color component.
* <p>
* The actual color used in rendering depends on finding the best
* match given the color space available for a given output device.
* @param rgb an integer giving the red, green, and blue components.
* @see java.awt.image.ColorModel#getRGBdefault
* @see java.awt.Color#getRed.
* @see java.awt.Color#getGreen.
* @see java.awt.Color#getBlue.
* @see java.awt.Color#getRGB.
* @since JDK1.0
*/
public Color(int rgb) {
value = 0xff000000 | rgb;
}
/**
* Creates a color with the specified red, green, and blue values,
* where each of the values is in the range 0.0-1.0. The value
* 0.0 indicates no contribution from the primary color component.
* The value 1.0 indicates the maximum intensity of the primary color
* component.
* <p>
* The actual color used in rendering depends on finding the best
* match given the color space available for a given output device.
* @param r the red component
* @param g the red component
* @param b the red component
* @see java.awt.Color#getRed.
* @see java.awt.Color#getGreen.
* @see java.awt.Color#getBlue.
* @see java.awt.Color#getRGB.
* @since JDK1.0
*/
public Color(float r, float g, float b) {
this( (int) (r * 255), (int) (g * 255), (int) (b * 255));
testColorValueRange(r,g,b);
}
/**
* Gets the red component of this color. The result is
* an integer in the range 0 to 255.
* @return the red component of this color.
* @see java.awt.Color#getRGB
* @since JDK1.0
*/
public int getRed() {
return (getRGB() >> 16) & 0xFF;
}
/**
* Gets the green component of this color. The result is
* an integer in the range 0 to 255.
* @return the green component of this color.
* @see java.awt.Color#getRGB
* @since JDK1.0
*/
public int getGreen() {
return (getRGB() >> 8) & 0xFF;
}
/**
* Gets the blue component of this color. The result is
* an integer in the range 0 to 255.
* @return the blue component of this color.
* @see java.awt.Color#getRGB
* @since JDK1.0
*/
public int getBlue() {
return (getRGB() >> 0) & 0xFF;
}
/**
* Gets the RGB value representing the color in the default RGB ColorModel.
* The red, green, and blue components of the color are each scaled to be
* a value between 0 (abscence of the color) and 255 (complete saturation).
* Bits 24-31 of the returned integer are 0xff, bits 16-23 are the red
* value, bit 8-15 are the green value, and bits 0-7 are the blue value.
* @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 brighter version of this color.
* <p>
* This method applies an arbitrary scale factor to each of the three RGB
* components of the color to create a brighter version of the same
* color. Although <code>brighter</code> and <code>darker</code> are
* inverse operations, the results of a series of invocations of
* these two methods may be inconsistent because of rounding errors.
* @return a new <code>Color</code> object,
* a brighter version of this color.
* @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 darker version of this color.
* <p>
* This method applies an arbitrary scale factor to each of the three RGB
* components of the color to create a darker version of the same
* color. Although <code>brighter</code> and <code>darker</code> are
* inverse operations, the results of a series of invocations of
* these two methods may be inconsistent because of rounding errors.
* @return a new <code>Color</code> object,
* a darker version of this color.
* @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 color.
* @return a hash code value for this object.
* @since JDK1.0
*/
public int hashCode() {
return value;
}
/**
* Determines whether another object is equal to this color.
* <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, and blue values as this object.
* @param obj the object to compare with.
* @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).value == this.value;
}
/**
* Creates a string that represents this color and indicates the
* values of its RGB components.
* @return a representation of this color as a
* <code>String</code> object.
* @since JDK1.0
*/
public String toString() {
return getClass().getName() + "[r=" + getRed() + ",g=" + getGreen() + ",b=" + getBlue() + "]";
}
/**
* Converts a string to an integer and returns the
* specified color. This method handles string formats that
* are used to represent octal and hexidecimal numbers.
* @param nm a string that represents
* a color as a 24-bit integer.
* @return the new color
* @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 color.
* <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 color value of the 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 color.
* <p>
* If the specified property is not found, or cannot be parsed as
* an integer, then the color specified by the second argument is
* returned instead.
* @param nm the name of the color property
* @param v the default color value.
* @return the color value of the 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, 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 color.
* <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 color.
* @param nm the name of the color property.
* @param v the default color value, as an integer.
* @return the color value of the 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, 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 RGB model.
* <p>
* The integer that is returned by <code>HSBtoRGB</code> encodes the
* value of a color in bits 0&endash;23 of an integer value, the same
* format used by the method <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)
* @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);
} else {
double h = (hue - Math.floor(hue)) * 6.0;
double f = h - java.lang.Math.floor(h);
double p = brightness * (1.0 - saturation);
double q = brightness * (1.0 - saturation * f);
double t = brightness * (1.0 - (saturation * (1.0 - f)));
switch ((int) h) {
case 0:
r = (int) (brightness * 255);
g = (int) (t * 255);
b = (int) (p * 255);
break;
case 1:
r = (int) (q * 255);
g = (int) (brightness * 255);
b = (int) (p * 255);
break;
case 2:
r = (int) (p * 255);
g = (int) (brightness * 255);
b = (int) (t * 255);
break;
case 3:
r = (int) (p * 255);
g = (int) (q * 255);
b = (int) (brightness * 255);
break;
case 4:
r = (int) (t * 255);
g = (int) (p * 255);
b = (int) (brightness * 255);
break;
case 5:
r = (int) (brightness * 255);
g = (int) (p * 255);
b = (int) (q * 255);
break;
}
}
return 0xff000000 | (r << 16) | (g << 8) | (b << 0);
}
/**
* Converts the components of a color, as specified by the RGB
* model, to an equivalent set of values for hue, saturation, and
* brightness, 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 to be 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)
* @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 values supplied
* for the HSB color model.
* <p>
* Each of the three components should be a floating-point
* value between zero and one (a number in the range
* <code>0.0</code> ≤ <code>h</code>, <code>s</code>,
* <code>b</code> ≤ <code>1.0). </code>
* @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));
}
}