rect = canvas.getBoundingClientRect();
		const sx = e.clientX - canvas_rect.left;
		const sy = e.clientY - canvas_rect.top;
		if(mousedown_sx == mousemove_sx && mousedown_sy == mousemove_sy) {
			const functions = s2x_x2s_s2y_y2s_from_UI();
			const s2x = functions[0];
			const s2y = functions[2];
			document.getElementById("center_x").value = s2x(sx).toFixed(5);
			document.getElementById("center_y").value = s2y(sy).toFixed(5);
			draw_canvas();
		}
	}, false);

	canvas.addEventListener('pointermove', func