frameworks/projects/framework/src/mx/utils/HSBColor.as

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////////////////////////////////////////////////////////////////////////////////

package mx.utils
{
/**
 * This class holds information for a color represented in HSB (Hue, Saturation, 
 * and Brightness) space. The main use of the class is simply as storage for
 * these values, but there are also some utility functions for converting
 * from and to RGB representations of colors.
 *  
 *  @langversion 3.0
 *  @playerversion Flash 10
 *  @playerversion AIR 1.5
 *  @productversion Flex 4
 */
public final class HSBColor
{
    /**
     *  Constructs an HSBColor with optional parameters.
     *
     *  @param hue The hue.
     *
     *  @param saturation The saturation.
     *
     *  @param brightness The brightness.
     *  
     *  @langversion 3.0
     *  @playerversion Flash 10
     *  @playerversion AIR 1.5
     *  @productversion Flex 4
     */
    public function HSBColor(hue:Number = NaN, saturation:Number = NaN, 
        brightness:Number = NaN)
    {
        this.hue = hue;
        this.saturation = saturation;
        this.brightness = brightness;
    }
    
    private var _hue:Number;
    /**
     * The hue value for the HSB color. This represents an angle, in 
     * degrees, around the HSB cone. The supplied value will be modulated
     * by 360 so that the stored value of hue will be in the range [0,360).
     *  
     *  @langversion 3.0
     *  @playerversion Flash 10
     *  @playerversion AIR 1.5
     *  @productversion Flex 4
     */
    public function get hue():Number
    {
        return _hue;
    }
    public function set hue(value:Number):void
    {
        _hue = value % 360;
    }
    
    private var _saturation:Number;
    /**
     * The saturation parameter for this HSB color. This is a value between
     * 0 (black) and 1 (full saturation), which represents the distance
     * from the center in the HSB cone.
     *  
     *  @langversion 3.0
     *  @playerversion Flash 10
     *  @playerversion AIR 1.5
     *  @productversion Flex 4
     */
    public function get saturation():Number
    {
        return _saturation;
    }
    public function set saturation(value:Number):void
    {
        _saturation = value;
    }
    
    private var _brightness:Number;
    /**
     * The brightness parameter for this HSB color. This is a value between
     * 0 (black) and 1 (full brightness), which represents the distance
     * from the apex of the HSB cone.
     *  
     *  @langversion 3.0
     *  @playerversion Flash 10
     *  @playerversion AIR 1.5
     *  @productversion Flex 4
     */
    public function get brightness():Number
    {
        return _brightness;
    }
    public function set brightness(value:Number):void
    {
        _brightness = value;
    }
    
    /**
     *  Converts an HSB color specified by the parameters to a
     *  uint RGB color.
     *
     *  @param hue The hue.
     *
     *  @param saturation The saturation.
     *
     *  @param brightness The brightness.
     *
     *  @return An RGB color.
     *  
     *  @langversion 3.0
     *  @playerversion Flash 10
     *  @playerversion AIR 1.5
     *  @productversion Flex 4
     */
    public static function convertHSBtoRGB(hue:Number, saturation:Number, 
        brightness:Number):uint
    {
        // Conversion taken from Foley, van Dam, et al
        var r:Number, g:Number, b:Number;
        if (saturation == 0)
        {
            r = g = b = brightness;
        }
        else
        {
            var h:Number = (hue % 360) / 60;
            var i:int = int(h);
            var f:Number = h - i;
            var p:Number = brightness * (1 - saturation);
            var q:Number = brightness * (1 - (saturation * f));
            var t:Number = brightness * (1 - (saturation * (1 - f)));
            switch (i) {
                case 0:
                    r = brightness;
                    g = t;
                    b = p;
                    break; 
                case 1:
                    r = q;                    
                    g = brightness;
                    b = p;
                    break; 
                case 2:
                    r = p;
                    g = brightness;
                    b = t; 
                    break;
                case 3:
                    r = p;
                    g = q;
                    b = brightness;
                    break; 
                case 4:
                    r = t;
                    g = p;
                    b = brightness; 
                    break;
                case 5: 
                    r = brightness;
                    g = p;
                    b = q;
                    break;
            }
        }
        r *= 255;
        g *= 255;
        b *= 255;
        return (r << 16 | g << 8 | b);
    }
    
    /**
     *  Converts a color from RGB format into an HSBColor.
     *
     *  @param rgb The RGB color.
     *
     *  @return The HSBColor object representing the RGB color. 
     *  
     *  @langversion 3.0
     *  @playerversion Flash 10
     *  @playerversion AIR 1.5
     *  @productversion Flex 4
     */
    static public function convertRGBtoHSB(rgb:uint):HSBColor
    {
        // Conversion taken from Foley, van Dam, et al
        var hue:Number, saturation:Number, brightness:Number;
        var r:Number = ((rgb >> 16) & 0xff) / 255;
        var g:Number = ((rgb >> 8) & 0xff) / 255;
        var b:Number = (rgb & 0xff) / 255;
        var max:Number = Math.max(r, Math.max(g, b));
        var min:Number = Math.min(r, Math.min(g, b));
        var delta:Number = max - min;
        brightness = max;
        if (max != 0)
            saturation = delta / max;
        else
            saturation = 0;
        if (saturation == 0)
            hue = NaN;
        else
        {
            if (r == max)
                hue = (g - b) / delta;
            else if (g == max)
                hue = 2 + (b - r) / delta
            else if (b == max)
                hue = 4 + (r - g) / delta;
            hue = hue * 60;
            if (hue < 0)
                hue += 360;
        }
        return new HSBColor(hue, saturation, brightness);
    }
}
}