A small tool for packing multiple images into one

At the time I couldn't find an easy online tool for creating spritesheets, so I created one myself. The controls are custom, and the images are rendered into a canvas. It also supports exporting the image with a json spritesheet file, so the sprites can be accessed in whatever tool/engine desired (the format matched the one by the great TexturePacker).

I also started on a polygon extraction, so sprites can be packed tigher, and rendered with less alpha overdraw. It worked for basic examples, but sadly I never got it to a state I was happy with.