A method includes displaying a background image on a display screen. The method further includes receiving, from an input device, a signal indicative of a free hand line being drawn over the background image. The signal includes coordinates of points of the free hand line with respect to the display screen. The free hand line is independent of content represented in the background image. The method further includes storing the signal in a storage device. The method further includes generating a smooth stiff line based on the stored signal. The method further includes displaying the smooth stiff line over the background image.