ns = s2x_x2s_s2y_y2s();
		const s2x = functions[0];
		const s2y = functions[2];
		const xy = [s2x(sx), s2y(sy)];
		if(e.buttons == 1) {
			points[points_i] = xy;
		}
		draw_canvas();
	}, false);

	i_canvas.addEventListener('pointerdown', function(e) {
		const canvas_rect = i_canvas.getBoundingClientRect();
		const sx = e.clientX - canvas_rect.left;
		const sy = e.clientY - canvas_rect.top;
		const functions = s2x_x2s_s2y_y2s();
		const s2x = functions[0];
		const s2y = functions[2];
		const xy = [s2x(sx), s