Function CheckOverflow

src/viewport.cpp:3061–3067

* Check for overflowing the map. * @param test the variable to test for overflowing * @param other the other variable to update to keep the line * @param max the maximum value for the \c test variable * @param mult the constant to multiply the difference by for \c other */

 * @param mult  the constant to multiply the difference by for \c other
 */
static void CheckOverflow(int &test, int &other, int max, int mult)
{
	if (test <= max) return;

	other += mult * (test - max);
	test = max;
}

/** while dragging */
static void CalcRaildirsDrawstyle(int x, int y, int method)