timdown

var trimCanvas = (function() {
    function rowBlank(imageData, width, y) {
        for (var x = 0; x < width; ++x) {
            if (imageData.data[y * width * 4 + x * 4 + 3] !== 0) return false;
        }
        return true;
    }

    function columnBlank(imageData, width, x, top, bottom) {
        for (var y = top; y < bottom; ++y) {