A method allows changing an image raster direction from an application raster direction to a screen raster direction, in-flight while pixel values of an image are transferred successively from an application output memory to a display unit. A single buffer memory array is implemented between the application output memory and the display unit. Two writing orders for cells of the buffer memory array are used in turn, each being combined with a different reading order for the cells. The method can be hardware-implemented, and is adapted for burst-handling of the pixel values.