quick-tile.js

var minX = 0, maxX = 0;
        var minY = 0, maxY = 0;
        if(scroll.x > 0) {
            maxX = scroll.x % paisley.width;
            minX = maxX > 0 ? -paisley.width + maxX : (maxX < 0 ? -paisley.width + maxX : 0);
        } else if(scroll.x < 0) {
            minX = scroll.x % paisley.width;
            minX = minX == 0 ? 0 : minX;
            maxX = minX + canvas.width;
            maxX = maxX >= canvas.width ? minX : maxX;
        }
        if(scroll.y > 0) {
            maxY = scroll.y % paisley.height;
            minY = maxY > 0 ? -paisley.height + maxY : (maxY < 0 ? -paisley.height + maxY : 0);
        } else if(scroll.y < 0) {
            minY = scroll.y % paisley.height;
            minY = minY == 0 ? 0 : minY;
            maxY = minY + canvas.height;
            maxY = maxY >= canvas.height ? minY : maxY;
        }
        while(minX <= maxX) {
            var y = minY;
            while(y <= maxY) {
                ctx.drawImage(paisley, minX, y);
                y += paisley.height;
            }
            minX += paisley.width;
        }