// Paint Colour Mixer
// copyright Stephen Chapman, 13th April 2006
// you may copy this code but please keep the copyright notice as well
var baseC = '256,256,256'; var redC = '-2,-8,-8'; var blueC = '-8,-8,-2'; var yellowC = '0,0,-8'; var orangeC = '1,1,0'; var greenC = '-4,0,-3'; var purpleC = '1,0,1'; var blackC = '-3,-4,-1'; var redV = blueV = yellowV = 0;
function limit(val) {if (val > 32) val = 32; if (val < 0) val = 0; return val;}
function change(r,y,b) {redV = limit(redV + r);  yellowV = limit(yellowV + y);  blueV = limit(blueV + b); var shade = new mathArray(baseC);var tot = redV + blueV + yellowV; if (tot > 0) {var redA = new mathArray(redC);redA.multiply(redV*redV/tot);shade.add(redA);var blueA = new mathArray(blueC);blueA.multiply(blueV*blueV/tot);shade.add(blueA);var yellowA = new mathArray(yellowC);yellowA.multiply(yellowV*yellowV/tot);shade.add(yellowA);var orangeA = new mathArray(orangeC);orangeA.multiply((redV * yellowV) /32);shade.add(orangeA);var greenA = new mathArray(greenC);greenA.multiply((blueV * yellowV) /32);shade.add(greenA);var purpleA = new mathArray(purpleC);purpleA.multiply((blueV * redV) /32);shade.add(purpleA);var blackA = new mathArray(blackC);blackA.multiply((blueV * redV * yellowV) /1024);shade.add(blackA);}shade.max(255);shade.min(0);shade.intg();document.getElementById('patch').style.backgroundColor = 'rgb(' + shade.value[0] + ',' + shade.value[1] + ',' + shade.value[2] + ')';}