Canvas - floodfill leaves white pixels at edges

Question

I am creating a drawing app. I have succeeded to do everything. When I paint the image with a dark color, some white pixels appear at the edges. I tried to change the value

Answer 1

Your check for the outline is simply too strict, marking light gray pixels as ones you cannot color in. I simply tweaked your threshholds:

function matchOutlineColor (r,g,b,a,e) {
  return a >= 150;
}

Notice my much higher numbers for the white value and alpha. You could maybe tweak this further but this looks good to me. Here are some before and after photos:

Before (zoomed in 200%)

After (zoomed in 200%)