Soft Paint Bucket Fill: Colour Equality

Question

I\'m making a small app where children can fill preset illustrations with colours. I\'ve succesfully implemented an MS-paint style paint bucket using the flood fill argorith

Answer 1

Made something that works:

                c = b.getPixel(xx,yy);
                if (c == to) continue;
                if (c != from) d = 
                    Math.pow(f1 - (c & 0xFF), 2) +
                    Math.pow(f2 - (c >> 8 & 0xFF), 2) +
                    Math.pow(f3 - (c >> 16 & 0xFF), 2)
                if (c == from || d < tres) {

Answer 2

well, i guess the most natural approach is to calculate the difference between to colors. to achieve a sensible value, one should calculate the difference per channel. haven't tested it, but the following should work:

const perChanThreshold:uint = 5;
const overallThreshold:uint = perChanThreshold * perChanThreshold * 3;
function match(source:uint, target:uint):Boolean {
    var diff:uint = 0, chanDiff:uint;
    for (var i:int = 0; i < 3; i++) {
        chanDiff = (source >> (i * 8)) & 0xFF;
        diff += chanDiff * chanDiff;
    }
    return diff <= overallThreshold;
}