Here is a simple Javascript class to calculate the percent of a gradient between two colors given the percent (as a float 0-1) and two colors. Uses functions from php.js.
Color = function() {
};
Color.hexdec = function(hex_string) {
hex_string = (hex_string + '').replace(/[^a-f0-9]/gi, '');
return parseInt(hex_string, 16);
}
Color.dechex = function(number) {
if (number < 0) {
number = 0xFFFFFFFF + number + 1;
}
return parseInt(number, 10).toString(16);
}
Color.pad = function(number, length) {
var str = '' + number;
while (str.length < length) {
str = '0' + str;
}
return str;
}
Color.calcgrad = function(val, color1, color2) {
if(!color1.match(/^#[0-9a-f]{6}/) || !color2.match(/^#[0-9a-f]{6}/)) return 'match err!';
if (val > 1) {
val = 1;
}
if (val < 0) {
val = 0;
}
val = parseFloat(val);
c1 = [Color.hexdec(color1.substr(1,2)), Color.hexdec(color1.substr(3,2)), Color.hexdec(color1.substr(5,2))];
c2 = [Color.hexdec(color2.substr(1,2)), Color.hexdec(color2.substr(3,2)), Color.hexdec(color2.substr(5,2))];
if (val < .5) {
delta = [(c2[0] - c1[0]), (c2[1] - c1[1]), (c1[2] - c2[2])];
arrColor = [c1[0] +1 * 2), c1[1] -2 * 2), c1[2] -3 * 2)];
}
return '#'+Color.pad(Color.dechex(arrColor[0]),2)+Color.pad(Color.dechex(arrColor[1]),2)+Color.pad(Color.dechex(arrColor[2]),2);
}
