path: root/java/awt/Color.java

/* Color.java -- Class representing a color in Java
   Copyright (C) 1999 Free Software Foundation, Inc.

This file is part of the non-peer AWT libraries of GNU Classpath.

This library is free software; you can redistribute it and/or modify
it under the terms of the GNU Library General Public License as published 
by the Free Software Foundation, either version 2 of the License, or
(at your option) any later verion.

This library is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Library General Public License for more details.

You should have received a copy of the GNU Library General Public License
along with this library; if not, write to the Free Software Foundation
Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307 USA. */


package java.awt;

/**
  * This class represents a color value in the AWT system.
  *
  * @author Aaron M. Renn (arenn@urbanophile.com)
  */
public class Color implements java.io.Serializable
{

/*
 * Static Variables
 */

/**
  * Constant for the color white
  */
public static final Color white = new Color(255,255,255);

/**
  * Constant for the color light gray
  */
public static final Color lightGray = new Color(192,192,192);

/**
  * Constant for the color gray
  */
public static final Color gray = new Color(128,128,128);

/**
  * Constant for the color dark gray
  */
public static final Color darkGray = new Color(64,64,64);

/**
  * Constant for the color black
  */
public static final Color black = new Color(0,0,0);

/**
  * Constant for the color red
  */
public static final Color red = new Color(255,0,0);

/**
  * Constant for the color pink
  */
public static final Color pink = new Color(255, 175, 175);

/**
  * Constant for the color orange
  */
public static final Color orange = new Color(255, 200, 0);

/**
  * Constant for the color yellow
  */
public static final Color yellow = new Color(255,255,0);

/**
  * Constant for the color green
  */
public static final Color green = new Color(0,255,0);

/**
  * Constant for the color magenta
  */
public static final Color magenta = new Color(255,0,255);

/**
  * Constant for the color cyan
  */
public static final Color cyan = new Color(0,255,255);

/**
  * Constant for the color blue
  */
public static final Color blue = new Color(0,0,255);

// Serialization Constant
private static final long serialVersionUID = 118526816881161077L;

// Masks for individual color components
private static final int redmask = 255 << 16;
private static final int greenmask = 255 << 8;
private static final int bluemask = 255;

/*************************************************************************/

/*
 * Instance Variables
 */

/**
  * @serial The RGB value of the color.
  */
private int value;

/*************************************************************************/

/*
 * Static Methods
 */

/**
  * Converts the specified string to a number and creates a new instance
  * of <code>Color</code> from the value.
  *
  * @param str The numeric color string.
  *
  * @return A new instance of <code>Color</code> for the string.
  *
  * @exception NumberFormatException If the string cannot be parsed.
  */
public static Color
decode(String str) throws NumberFormatException
{
  Integer i = Integer.decode(str);
  return(new Color(i.intValue()));
}

/*************************************************************************/

/**
  * Returns a new instance of <code>Color</code> from the value of
  * the system property named by the specified string.  If the property
  * does not exist, or cannot be parsed, then <code>null</code> will be
  * returned.
  *
  * @param prop The system property to retrieve.
  */
public static Color
getColor(String prop)
{
  return(getColor(prop, null));
}

/*************************************************************************/

/**
  * Returns a new instance of <code>Color</code> from the value of the
  * system property named by the specified string.  If the property does
  * not exist, or cannot be parsed, then the default RGB value will be
  * used to create a return value.
  *
  * @param prop The system property to retrieve.
  * @param defrgb The default RGB value.
  */
public static Color
getColor(String prop, int defrgb)
{
  return(getColor(prop, new Color(defrgb)));
}

/*************************************************************************/

/**
  * Returns a new instance of <code>Color</code> from the value of the
  * system property named by the specified string.  If the property does
  * not exist, or cannot be parsed, then the default color value will be
  * returned
  *
  * @param prop The system property to retrieve.
  * @param defcolor The default color
  */
public static Color
getColor(String prop, Color defcolor)
{
  String val = System.getProperty(prop);
  if (val == null)
    return(defcolor);

  try
    {
      return(decode(val));
    }
  catch(NumberFormatException e)
    {
      return(defcolor);
    }
}

/*************************************************************************/

/**
  * Converts from the HSB (hue, saturation, brightness) color model to
  * the RGB (red, green, blue) color model.
  *
  * @param hue The hue of the HSB value.
  * @param saturation The saturation of the HSB value.
  * @param brightness The brightness of the HSB value.
  *
  * @return The RGB value.
  */
public static int
HSBtoRGB(float hue, float saturation, float brightness)
{
  // FIXME: Implement
  throw new RuntimeException("Not implemented yet");
}

/*************************************************************************/

/**
  * Converts from the RGB (red, green, blue) color model to the HSB
  * (hue, saturation, brightness) color model.
  *
  * @param red The red part of the RGB value.
  * @param green The green part of the RGB value.
  * @param blue The blue part of the RGB value.
  * @param hsbvals An array of three floats used for storing the HSB values,
  * or <code>null</code> if this return mechanism is not used.
  *
  * @return The HSB value.
  */
public static float[]
RGBtoHSB(int red, int green, int blue, float hsbvals[])
{
  // FIXME: Implement
  throw new RuntimeException("Not implemented yet");
}

/*************************************************************************/

/**
  * Returns a new instance of <code>Color</code> based on the specified
  * HSB values.
  *
  * @param hue The hue of the HSB value.
  * @param saturation The saturation of the HSB value.
  * @param brightness The brightness of the HSB value.
  *
  * @return The new <code>Color</code> object.
  */
public static Color
getHSBColor(float hue, float saturation, float brightness)
{
  return(new Color(HSBtoRGB(hue, saturation, brightness)));
}

/*************************************************************************/

/*
 * Constructors
 */

/**
  * Initializes a new instance of <code>Color</code> using the specified
  * red, green, and blue values, which must be given as integers in the
  * range of 0-255.
  *
  * @param red The red component of the RGB value.
  * @param green The green component of the RGB value.
  * @param blue The blue component of the RGB value.
  *
  * @exception IllegalArgumentException If the values are out of range.
  */
public
Color(int red, int green, int blue)
{
  if ((red < 0) || (red > 255) || (green < 0) || (green > 255) ||
      (blue < 0) || (blue > 255))
    throw new IllegalArgumentException("Bad RGB values");

  value = blue + (green << 8) + (red << 16);
}

/*************************************************************************/

/**
  * Initializes a new instance of <code>Color</code> using the specified
  * RGB value.  The blue value is in bits 0-7, green in bits 8-15, and 
  * red in bits 16-23.  The other bits are ignored.
  *
  * @param value The RGB value
  */
public
Color(int value)
{
  this.value = value;
}

/*************************************************************************/

/**
  * Initializes a new instance of <code>Color</code> using the specified
  * RGB values.  These must be in the range of 0.0-1.0.
  *
  * @param red The red component of the RGB value.
  * @param green The green component of the RGB value.
  * @param blue The blue component of the RGB value.
  *
  * @exception IllegalArgumentException If the values are out of range.
  */
public
Color(float red, float green, float blue)
{
  if ((red < 0.0) || (red > 1.0) || (green < 0.0) || (green > 1.0) ||
      (blue < 0.0) || (blue > 1.0))
    throw new IllegalArgumentException("Bad RGB values");

  int redval = (int)(255 * red);
  int greenval = (int)(255 * green);
  int blueval = (int)(255 * blue);

  value = blueval + (greenval << 8) + (redval << 16);
}

/*************************************************************************/

/*
 * Instance Methods
 */

/**
  * Returns the red value for this color.
  *
  * @return The red value for this color.
  */
public int
getRed()
{
  int redval = (value & redmask) >> 16;

  return(redval);
}

/*************************************************************************/

/**
  * Returns the green value for this color.
  *
  * @return The green value for this color.
  */
public int
getGreen()
{
  int greenval = (value & greenmask) >> 8;

  return(greenval);
}

/*************************************************************************/

/**
  * Returns the blue value for this color.
  *
  * @return The blue value for this color.
  */
public int
getBlue()
{
  int blueval = (value & bluemask);

  return(blueval);
}

/*************************************************************************/

/**
  * Returns the RGB value for this color.  The blue value will be in bits
  * 0-7, green in 8-15, and red in 6-23.  The upper bits should be ignored.
  *
  * @return The RGB value for this color.
  */
public int
getRGB()
{
  return(value);
}

/*************************************************************************/

/**
  * Returns a brighter version of this color.  This is done by increasing
  * the RGB values by an arbitrary scale factor.  Note that this method
  * and the <code>darker()</code> method are not necessarily inverses.
  *
  * @return A brighter version of this color.
  */
public Color
brighter()
{
  int red = getRed();
  int green = getGreen();
  int blue = getBlue();

  red += 10;
  green += 10;
  blue += 10;

  if (red > 255)
    red = 255;
  if (green > 255)
    green = 255;
  if (blue > 255)
    blue = 255;

  return(new Color(red, green, blue));
}

/*************************************************************************/

/**
  * Returns a darker version of this color.  This is done by decreasing
  * the RGB values by an arbitrary scale factor.  Note that this method
  * and the <code>brighter()</code> method are not necessarily inverses.
  *
  * @return A darker version of this color.
  */
public Color
darker()
{
  int red = getRed();
  int green = getGreen();
  int blue = getBlue();

  red -= 10;
  green -= 10;
  blue -= 10;

  if (red < 0)
    red = 0;
  if (green < 0)
    green = 0;
  if (blue < 0)
    blue = 0;

  return(new Color(red, green, blue));
}

/*************************************************************************/

/**
  * Returns a hash value for this color.
  *
  * @return A hash value for this color.
  */
public int
hashCode()
{
  return(value);
}

/*************************************************************************/

/**
  * Tests this object for equality against the specified object.  This will
  * be true if and only if the specified object is an instance of
  * <code>Color</code> and has the same red, green, and blue values as
  * this object.
  *
  * @return <code>true</code> if the specified object is equal to this one,
  * <code>false</code> otherwise.
  */
public boolean
equals(Object obj)
{
  if (obj == null)
    return(false);

  if (!(obj instanceof Color))
    return(false);

  Color c = (Color)obj;

  if (c.getRed() != getRed())
    return(false);
  if (c.getGreen() != getGreen())
    return(false);
  if (c.getBlue() != getBlue())
    return(false);

  return(true);
}

/*************************************************************************/

/**
  * Returns a string representation of this object.
  * 
  * @return A string representation of this object.
  */
public String
toString()
{
  return(getClass().getName() + "(red=" + getRed() + ",green=" + getGreen() +
         ",blue=" + getBlue() + ")");
}

} // class Color