gistfile1.txt

        sendStrokes();
        // find bounding box on strokes
        var minx = strokes[0][0].x, miny = strokes[0][0].y, maxx = strokes[0][1].x, maxy = strokes[0][1].y;
        for (var i = 0; i < strokes.length; i++) {
            var stroke = strokes[i];
            for (var j = 0; j < stroke.length; j++) {
                var x = stroke[j].x;
                var y = stroke[j].y;
                if (x < minx) {
                    minx = x;
                }
                if (x > maxx) {
                    maxx = x;
                }
                if (y < miny) {
                    miny = y;
                }
                if (Y > maxy) {
                    maxy = y;
                }
            }
        }
        console.log(minx,miny,maxx,maxy);
        var a = maxx + 30;
        var b = (maxy + miny)/2;
        // draw equal sign
        ctx.beginPath();
        ctx.moveTo(a,b);
        ctx.lineTo(a+20,b);
        ctx.stroke();
        
        ctx.beginPath();
        ctx.moveTo(a,b+10);
        ctx.lineTo(a+20,b+10);
        ctx.stroke();