王咏刚，2005年4月
在这种使用了HSB色环的调色版组件中，最重要的基本函数是HSB和RGB色彩空间的相互转换。网上好像有很多人在找类似的代码，实际上，Java API中的Color类就包含这样的函数，而Java SDK又提供了源代码，我们可以直接把Java代码改为Flash用的JavaScript代码。下面是我的修改结果：
public static function hsb2rgb(hue:Number, saturation:Number, brightness:Number):Number {
var r, g, b, h, f, p, q, t;
var rgbvals = new Array(3);
hue /= 360; saturation /= 100; brightness /= 100;
if (saturation == 0) {
r = g = b = Math.floor(brightness * 255.0 + 0.5);
} else {
h = (hue - Math.floor(hue)) * 6.0;
f = h - Math.floor(h);
p = brightness * (1.0 - saturation);
q = brightness * (1.0 - saturation * f);
t = brightness * (1.0 - (saturation * (1.0 - f)));
switch (Math.floor(h)) {
case 0:
r = Math.floor(brightness * 255.0 + 0.5);
g = Math.floor(t * 255.0 + 0.5);
b = Math.floor(p * 255.0 + 0.5);
break;
case 1:
r = Math.floor(q * 255.0 + 0.5);
g = Math.floor(brightness * 255.0 + 0.5);
b = Math.floor(p * 255.0 + 0.5);
break;
case 2:
r = Math.floor(p * 255.0 + 0.5);
g = Math.floor(brightness * 255.0 + 0.5);
b = Math.floor(t * 255.0 + 0.5);
break;
case 3:
r = Math.floor(p * 255.0 + 0.5);
g = Math.floor(q * 255.0 + 0.5);
b = Math.floor(brightness * 255.0 + 0.5);
break;
case 4:
r = Math.floor(t * 255.0 + 0.5);
g = Math.floor(p * 255.0 + 0.5);
b = Math.floor(brightness * 255.0 + 0.5);
break;
case 5:
r = Math.floor(brightness * 255.0 + 0.5);
g = Math.floor(p * 255.0 + 0.5);
b = Math.floor(q * 255.0 + 0.5);
break;
}
}
rgbvals[0] = r;
rgbvals[1] = g;
rgbvals[2] = b;
return rgbvals;
}
public static function hsb2rgbValue(hue:Number, saturation:Number, brightness:Number):Number {
var rgbvals = hsb2rgb(hue, saturation, brightness);
return (rgbvals[0] << 16) | (rgbvals[1] << 8) | (rgbvals[2] << 0);
}
public static function rgb2hsb(r:Number, g:Number, b:Number):Array {
var hue, saturation, brightness;
var hsbvals = new Array(3);
var cmax = (r > g) ? r : g;
if (b > cmax) cmax = b;
var cmin = (r < g) ? r : g;
if (b < cmin) cmin = b;
brightness = cmax / 255.0;
if (cmax != 0)
saturation = (cmax - cmin) / cmax;
else
saturation = 0;
if (saturation == 0)
hue = 0;
else {
var redc = (cmax - r) / (cmax - cmin);
var greenc = (cmax - g) / (cmax - cmin);
var bluec = (cmax - b) / (cmax - cmin);
if (r == cmax)
hue = bluec - greenc;
else if (g == cmax)
hue = 2.0 + redc - bluec;
else
hue = 4.0 + greenc - redc;
hue = hue / 6.0;
if (hue < 0)
hue = hue + 1.0;
}
hsbvals[0] = Math.floor(hue * 360 + 0.5);
hsbvals[1] = Math.floor(saturation * 100 + 0.5);
hsbvals[2] = Math.floor(brightness * 100 + 0.5);
return hsbvals;
}
public static function rgbValue2hsb(rgb:Number):Array {
var r = rgb >> 16;
var g = (rgb - (r << 16)) >> 8;
var b = rgb - (r << 16) - (g << 8);
return rgb2hsb(r, g, b);
}
……未完待续……