Creating a path from the edge of an image

Question

I have a binary image (e.g., .png) with background transparency. Let\'s say it looks like a blob with an irregular, but solid shape (no holes and it\'s all in one piece).

Answer 1

This is pure JS solution without depending on any 3rd party library.

function getOutline(ctx,pointX,pointY,w,h){
    var imageData = ctx.getImageData(pointX, pointY, w, h);
    var data = imageData.data;
    var outline=[];
    for(var x=0;x

Demo