/*
 * @(#)GTKColorType.java	1.6 03/01/23
 *
 * Copyright 2003 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
package com.sun.java.swing.plaf.gtk;

import java.awt.Color;
import javax.swing.plaf.ColorUIResource;

/**
 * @version 1.6, 01/23/03
 * @author Scott Violet
 */
class GTKColorType extends ColorType {
    // GTK allows you to specify the foreground and background in a
    // gtkrc, the rest (dark, mid, light) are calculated from these
    // values.
    public static final ColorType LIGHT = new GTKColorType("Light");
    public static final ColorType DARK = new GTKColorType("Dark");
    public static final ColorType MID = new GTKColorType("Mid");
    public static final ColorType BLACK = new GTKColorType("Black");
    public static final ColorType WHITE = new GTKColorType("White");

    public static final int MAX_COUNT;

    private static final float[] HLS_COLORS = new float[3];
    private static final Object HLS_COLOR_LOCK = new Object();

    static {
        MAX_COUNT = WHITE.getID() + 1;
    }

    private static int hlsToRGB(float h, float l, float s) {
        float m2 = (l <= .5f) ? (l * (1 + s)) : (l + s - l * s);
        float m1 = 2.0f * l - m2;
        float r, g, b;

        if (s == 0.0) {
            if (h == 0.0) {
                r = g = b = l;
            }
            else {
                r = g = b = 0;
            }
        }
        else {
            r = hlsValue(m1, m2, h + 120);
            g = hlsValue(m1, m2, h);
            b = hlsValue(m1, m2, h - 120);
        }
	return (((int)(r * 255)) << 16) | (((int)(g * 255.0)) << 8) |
	       ((int)(b * 255));
    }

    private static float hlsValue(float n1, float n2, float h) {
        if (h > 360) {
            h -= 360;
        }
        else if (h < 0) {
            h += 360;
        }
        if (h < 60) {
            return n1 + (n2 - n1) * h / 60.0f;
        }
        else if (h < 180) {
            return n2;
        }
        else if (h < 240) {
            return n1 + (n2 - n1) * (240.0f - h) / 60.0f;
        }
        return n1;
    }

    /**
     * Converts from RGB color space to HLS colorspace.
     */
    private static float[] rgbToHLS(int rgb, float[] hls) {
	float r = ((rgb & 0xFF0000) >> 16) / 255.0f;
	float g = ((rgb & 0xFF00) >> 8) / 255.0f;
	float b = (rgb & 0xFF) / 255.0f;

	/* calculate lightness */ 
	float max = Math.max(Math.max(r, g), b);
	float min = Math.min(Math.min(r, g), b);
	float l = (max + min) / 2.0f;
	float s = 0;
	float h = 0;

	if (max != min) {
            float delta = max - min;
            s = (l <= .5f) ? (delta / (max + min)) : (delta / (2.0f - max -min));
            if (r == max) {
                h = (g - b) / delta;
            }
            else if (g == max) {
                h = 2.0f + (b - r) / delta;
            }
            else {
                h = 4.0f + (r - g) / delta;
            }
            h *= 60.0f;
            if (h < 0) {
                h += 360.0f;
            }
        }
	if (hls == null) {
	    hls = new float[3];
	}
	hls[0] = h;
	hls[1] = l;
	hls[2] = s;
	return hls;
    }

    /**
     * Creates and returns a new color derived from the passed in color.
     * The transformation is done in the HLS color space using the specified
     * arguments to scale.
     *
     * @param color Color to alter
     * @param hFactory Amount to scale the hue
     * @param lFactor Amount to scale the lightness
     * @param sFactory Amount to sacle saturation
     * @return newly created color
     */
    static Color adjustColor(Color color, float hFactor, float lFactor,
                             float sFactor) {
        float h;
        float l;
        float s;

        synchronized(HLS_COLOR_LOCK) {
            float[] hls = rgbToHLS(color.getRGB(), HLS_COLORS);
            h = hls[0];
            l = hls[1];
            s = hls[2];
        }
        h = Math.min(360, hFactor * h);
        l = Math.min(1, lFactor * l);
        s = Math.min(1, sFactor * s);
        return new ColorUIResource(hlsToRGB(h, l, s));
    }

    protected GTKColorType(String name) {
        super(name);
    }
}