Class ColorUtil


  • public final class ColorUtil
    extends java.lang.Object
    A collection of utility methods for working with Colors.
    Author:
    joshua.marinacci@sun.com, Karl George Schaefer
    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static java.awt.Color blend​(java.awt.Color origin, java.awt.Color over)
      Blends two colors to create a new color.
      static java.awt.Color computeForeground​(java.awt.Color bg)
      Computes an appropriate foreground color (either white or black) for the given background color.
      static java.awt.Paint getCheckerPaint()
      Creates a new Paint that is a checkered effect using the colors gray and Color.WHITE.
      static java.awt.Paint getCheckerPaint​(java.awt.Color c1, java.awt.Color c2, int size)
      Creates a new Paint that is a checkered effect using the specified colors.
      static java.awt.Color interpolate​(java.awt.Color b, java.awt.Color a, float t)  
      static java.awt.Color removeAlpha​(java.awt.Color color)
      Returns a new color equal to the old one, except that there is no alpha (transparency) channel.
      static java.awt.Color setAlpha​(java.awt.Color color, int alpha)
      Returns a new color equal to the old one, except alpha (transparency) channel is set to the new value.
      static java.awt.Color setBrightness​(java.awt.Color color, float brightness)
      Returns a new color equal to the old one, except the brightness is set to the new value.
      static java.awt.Color setSaturation​(java.awt.Color color, float saturation)
      Returns a new color equal to the old one, except the saturation is set to the new value.
      static void tileStretchPaint​(java.awt.Graphics g, javax.swing.JComponent comp, java.awt.image.BufferedImage img, java.awt.Insets ins)
      Draws an image on top of a component by doing a 3x3 grid stretch of the image using the specified insets.
      static java.lang.String toHexString​(java.awt.Color color)
      Creates a String that represents the supplied color as a hex-value RGB triplet, including the "#".
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Method Detail

      • removeAlpha

        public static java.awt.Color removeAlpha​(java.awt.Color color)
        Returns a new color equal to the old one, except that there is no alpha (transparency) channel.

        This method is a convenience and has the same effect as setAlpha(color, 255).

        Parameters:
        color - the color to remove the alpha (transparency) from
        Returns:
        a new non-transparent Color
        Throws:
        java.lang.NullPointerException - if color is null
      • setAlpha

        public static java.awt.Color setAlpha​(java.awt.Color color,
                                              int alpha)
        Returns a new color equal to the old one, except alpha (transparency) channel is set to the new value.
        Parameters:
        color - the color to modify
        alpha - the new alpha (transparency) level. Must be an int between 0 and 255
        Returns:
        a new alpha-applied Color
        Throws:
        java.lang.IllegalArgumentException - if alpha is not between 0 and 255 inclusive
        java.lang.NullPointerException - if color is null
      • setSaturation

        public static java.awt.Color setSaturation​(java.awt.Color color,
                                                   float saturation)
        Returns a new color equal to the old one, except the saturation is set to the new value. The new color will have the same alpha (transparency) as the original color.

        The color is modified using HSB calculations. The saturation must be a float between 0 and 1. If 0 the resulting color will be gray. If 1 the resulting color will be the most saturated possible form of the passed in color.

        Parameters:
        color - the color to modify
        saturation - the saturation to use in the new color
        Returns:
        a new saturation-applied Color
        Throws:
        java.lang.IllegalArgumentException - if saturation is not between 0 and 1 inclusive
        java.lang.NullPointerException - if color is null
      • setBrightness

        public static java.awt.Color setBrightness​(java.awt.Color color,
                                                   float brightness)
        Returns a new color equal to the old one, except the brightness is set to the new value. The new color will have the same alpha (transparency) as the original color.

        The color is modified using HSB calculations. The brightness must be a float between 0 and 1. If 0 the resulting color will be black. If 1 the resulting color will be the brightest possible form of the passed in color.

        Parameters:
        color - the color to modify
        brightness - the brightness to use in the new color
        Returns:
        a new brightness-applied Color
        Throws:
        java.lang.IllegalArgumentException - if brightness is not between 0 and 1 inclusive
        java.lang.NullPointerException - if color is null
      • toHexString

        public static java.lang.String toHexString​(java.awt.Color color)
        Creates a String that represents the supplied color as a hex-value RGB triplet, including the "#". The return value is suitable for use in HTML. The alpha (transparency) channel is neither include nor used in producing the string.
        Parameters:
        color - the color to convert
        Returns:
        the hex String
      • computeForeground

        public static java.awt.Color computeForeground​(java.awt.Color bg)
        Computes an appropriate foreground color (either white or black) for the given background color.
        Parameters:
        bg - the background color
        Returns:
        Color.WHITE or Color.BLACK
        Throws:
        java.lang.NullPointerException - if bg is null
      • blend

        public static java.awt.Color blend​(java.awt.Color origin,
                                           java.awt.Color over)
        Blends two colors to create a new color. The origin color is the base for the new color and regardless of its alpha component, it is treated as fully opaque (alpha 255).
        Parameters:
        origin - the base of the new color
        over - the alpha-enabled color to add to the origin color
        Returns:
        a new color comprised of the origin and over colors
      • interpolate

        public static java.awt.Color interpolate​(java.awt.Color b,
                                                 java.awt.Color a,
                                                 float t)
      • getCheckerPaint

        public static java.awt.Paint getCheckerPaint()
        Creates a new Paint that is a checkered effect using the colors gray and Color.WHITE.
        Returns:
        a the checkered paint
      • getCheckerPaint

        public static java.awt.Paint getCheckerPaint​(java.awt.Color c1,
                                                     java.awt.Color c2,
                                                     int size)
        Creates a new Paint that is a checkered effect using the specified colors.

        While this method supports transparent colors, this implementation performs painting operations using the second color after it performs operations using the first color. This means that to create a checkered paint with a fully-transparent color, you MUST specify that color first.

        Parameters:
        c1 - the first color
        c2 - the second color
        size - the size of the paint
        Returns:
        a new Paint checkering the supplied colors
      • tileStretchPaint

        public static void tileStretchPaint​(java.awt.Graphics g,
                                            javax.swing.JComponent comp,
                                            java.awt.image.BufferedImage img,
                                            java.awt.Insets ins)
        Draws an image on top of a component by doing a 3x3 grid stretch of the image using the specified insets.

        TODO this is image related; move to GraphicsUtilities