import java.awt.Color;

/**

* The HSLColor class provides methods to manipulate HSL (Hue, Saturation

* Luminance) values to create a corresponding Color object using the RGB

* ColorSpace.

*

* The HUE is the color, the Saturation is the purity of the color (with

* respect to grey) and Luminance is the brightness of the color (with respect

* to black and white)

*

* The Hue is specified as an angel between 0 - 360 degrees where red is 0,

* green is 120 and blue is 240. In between you have the colors of the rainbow.

* Saturation is specified as a percentage between 0 - 100 where 100 is fully

* saturated and 0 approaches gray. Luminance is specified as a percentage

* between 0 - 100 where 0 is black and 100 is white.

*

* In particular the HSL color space makes it easier change the Tone or Shade

* of a color by adjusting the luminance value.

*/

public class HSLColor

{

private Color rgb;

private float[] hsl;

private float alpha;

/**

* Create a HSLColor object using an RGB Color object.

*

* @param rgb the RGB Color object

*/

public HSLColor(Color rgb)

{

this.rgb = rgb;

hsl = fromRGB( rgb );

alpha = rgb.getAlpha() / 255.0f;

}

/**

* Create a HSLColor object using individual HSL values and a default

* alpha value of 1.0.

*

* @param h is the Hue value in degrees between 0 - 360

* @param s is the Saturation percentage between 0 - 100

* @param l is the Lumanance percentage between 0 - 100

*/

public HSLColor(float h, float s, float l)

{

this(h, s, l, 1.0f);

}

/**

* Create a HSLColor object using individual HSL values.

*

* @param h the Hue value in degrees between 0 - 360

* @param s the Saturation percentage between 0 - 100

* @param l the Lumanance percentage between 0 - 100

* @param alpha the alpha value between 0 - 1

*/

public HSLColor(float h, float s, float l, float alpha)

{

hsl = new float[] {h, s, l};

this.alpha = alpha;

rgb = toRGB(hsl, alpha);

}

/**

* Create a HSLColor object using an an array containing the

* individual HSL values and with a default alpha value of 1.

*

* @param hsl array containing HSL values

*/

public HSLColor(float[] hsl)

{

this(hsl, 1.0f);

}

/**

* Create a HSLColor object using an an array containing the

* individual HSL values.

*

* @param hsl array containing HSL values

* @param alpha the alpha value between 0 - 1

*/

public HSLColor(float[] hsl, float alpha)

{

this.hsl = hsl;

this.alpha = alpha;

rgb = toRGB(hsl, alpha);

}

/**

* Create a RGB Color object based on this HSLColor with a different

* Hue value. The degrees specified is an absolute value.

*

* @param degrees - the Hue value between 0 - 360

* @return the RGB Color object

*/

public Color adjustHue(float degrees)

{

return toRGB(degrees, hsl[1], hsl[2], alpha);

}

/**

* Create a RGB Color object based on this HSLColor with a different

* Luminance value. The percent specified is an absolute value.

*

* @param percent - the Luminance value between 0 - 100

* @return the RGB Color object

*/

public Color adjustLuminance(float percent)

{

return toRGB(hsl[0], hsl[1], percent, alpha);

}

/**

* Create a RGB Color object based on this HSLColor with a different

* Saturation value. The percent specified is an absolute value.

*

* @param percent - the Saturation value between 0 - 100

* @return the RGB Color object

*/

public Color adjustSaturation(float percent)

{

return toRGB(hsl[0], percent, hsl[2], alpha);

}

/**

* Create a RGB Color object based on this HSLColor with a different

* Shade. Changing the shade will return a darker color. The percent

* specified is a relative value.

*

* @param percent - the value between 0 - 100

* @return the RGB Color object

*/

public Color adjustShade(float percent)

{

float multiplier = (100.0f - percent) / 100.0f;

float l = Math.max(0.0f, hsl[2] * multiplier);

return toRGB(hsl[0], hsl[1], l, alpha);

}

/**

* Create a RGB Color object based on this HSLColor with a different

* Tone. Changing the tone will return a lighter color. The percent

* specified is a relative value.

*

* @param percent - the value between 0 - 100

* @return the RGB Color object

*/

public Color adjustTone(float percent)

{

float multiplier = (100.0f + percent) / 100.0f;

float l = Math.min(100.0f, hsl[2] * multiplier);

return toRGB(hsl[0], hsl[1], l, alpha);

}

/**

* Get the Alpha value.

*

* @return the Alpha value.

*/

public float getAlpha()

{

return alpha;

}

/**

* Create a RGB Color object that is the complementary color of this

* HSLColor. This is a convenience method. The complementary color is

* determined by adding 180 degrees to the Hue value.

* @return the RGB Color object

*/

public Color getComplementary()

{

float hue = (hsl[0] + 180.0f) % 360.0f;

return toRGB(hue, hsl[1], hsl[2]);

}

/**

* Get the Hue value.

*

* @return the Hue value.

*/

public float getHue()

{

return hsl[0];

}

/**

* Get the HSL values.

*

* @return the HSL values.

*/

public float[] getHSL()

{

return hsl;

}

/**

* Get the Luminance value.

*

* @return the Luminance value.

*/

public float getLuminance()

{

return hsl[2];

}

/**

* Get the RGB Color object represented by this HDLColor.

*

* @return the RGB Color object.

*/

public Color getRGB()

{

return rgb;

}

/**

* Get the Saturation value.

*

* @return the Saturation value.

*/

public float getSaturation()

{

return hsl[1];

}

public String toString()

{

String toString =

"HSLColor[h=" + hsl[0] +

",s=" + hsl[1] +

",l=" + hsl[2] +

",alpha=" + alpha + "]";

return toString;

}

/**

* Convert a RGB Color to it corresponding HSL values.

*

* @return an array containing the 3 HSL values.

*/

public static float[] fromRGB(Color color)

{

// Get RGB values in the range 0 - 1

float[] rgb = color.getRGBColorComponents( null );

float r = rgb[0];

float g = rgb[1];

float b = rgb[2];

// Minimum and Maximum RGB values are used in the HSL calculations

float min = Math.min(r, Math.min(g, b));

float max = Math.max(r, Math.max(g, b));

// Calculate the Hue

float h = 0;

if (max == min)

h = 0;

else if (max == r)

h = ((60 * (g - b) / (max - min)) + 360) % 360;

else if (max == g)

h = (60 * (b - r) / (max - min)) + 120;

else if (max == b)

h = (60 * (r - g) / (max - min)) + 240;

// Calculate the Luminance

float l = (max + min) / 2;

// Calculate the Saturation

float s = 0;

if (max == min)

s = 0;

else if (l <= .5f)

s = (max - min) / (max + min);

else

s = (max - min) / (2 - max - min);

return new float[] {h, s * 100, l * 100};

}

/**

* Convert HSL values to a RGB Color with a default alpha value of 1.

* H (Hue) is specified as degrees in the range 0 - 360.

* S (Saturation) is specified as a percentage in the range 1 - 100.

* L (Lumanance) is specified as a percentage in the range 1 - 100.

*

* @param hsl an array containing the 3 HSL values

*

* @returns the RGB Color object

*/

public static Color toRGB(float[] hsl)

{

return toRGB(hsl, 1.0f);

}

/**

* Convert HSL values to a RGB Color.

* H (Hue) is specified as degrees in the range 0 - 360.

* S (Saturation) is specified as a percentage in the range 1 - 100.

* L (Lumanance) is specified as a percentage in the range 1 - 100.

*

* @param hsl an array containing the 3 HSL values

* @param alpha the alpha value between 0 - 1

*

* @returns the RGB Color object

*/

public static Color toRGB(float[] hsl, float alpha)

{

return toRGB(hsl[0], hsl[1], hsl[2], alpha);

}

/**

* Convert HSL values to a RGB Color with a default alpha value of 1.

*

* @param h Hue is specified as degrees in the range 0 - 360.

* @param s Saturation is specified as a percentage in the range 1 - 100.

* @param l Lumanance is specified as a percentage in the range 1 - 100.

*

* @returns the RGB Color object

*/

public static Color toRGB(float h, float s, float l)

{

return toRGB(h, s, l, 1.0f);

}

/**

* Convert HSL values to a RGB Color.

*

* @param h Hue is specified as degrees in the range 0 - 360.

* @param s Saturation is specified as a percentage in the range 1 - 100.

* @param l Lumanance is specified as a percentage in the range 1 - 100.

* @param alpha the alpha value between 0 - 1

*

* @returns the RGB Color object

*/

public static Color toRGB(float h, float s, float l, float alpha)

{

if (s <0.0f || s > 100.0f)

{

String message = "Color parameter outside of expected range - Saturation";

throw new IllegalArgumentException( message );

}

if (l <0.0f || l > 100.0f)

{

String message = "Color parameter outside of expected range - Luminance";

throw new IllegalArgumentException( message );

}

if (alpha <0.0f || alpha > 1.0f)

{

String message = "Color parameter outside of expected range - Alpha";

throw new IllegalArgumentException( message );

}

// Formula needs all values between 0 - 1.

h = h % 360.0f;

h /= 360f;

s /= 100f;

l /= 100f;

float q = 0;

if (l < 0.5)

q = l * (1 + s);

else

q = (l + s) - (s * l);

float p = 2 * l - q;

float r = Math.max(0, HueToRGB(p, q, h + (1.0f / 3.0f)));

float g = Math.max(0, HueToRGB(p, q, h));

float b = Math.max(0, HueToRGB(p, q, h - (1.0f / 3.0f)));

r = Math.min(r, 1.0f);

g = Math.min(g, 1.0f);

b = Math.min(b, 1.0f);

return new Color(r, g, b, alpha);

// return new Color((int)(r*255+0.5), (int)(g*255+0.5), (int)(b*255+0.5), (int)(alpha*255+0.5));

}

private static float HueToRGB(float p, float q, float h)

{

if (h < 0) h += 1;

if (h > 1 ) h -= 1;

if (6 * h < 1)

{

return p + ((q - p) * 6 * h);

}

if (2 * h < 1 )

{

return q;

}

if (3 * h < 2)

{

return p + ( (q - p) * 6 * ((2.0f / 3.0f) - h) );

}

return p;

}

}