| 摘要 |
PURPOSE:To rotate and plot a graphic at a high speed by shifting data on a horizontal display memory by a two-dimensional picture shifter and transferring this data to a vertical display memory. CONSTITUTION:When a 90 deg. rotation command and rotation center coordinates are outputted from a CPU 1, the address of the boundary including rotation center coordinates is given to a first horizontal display memory and a vertical display memory 7. Address conversion and calculation of the extent of shift are performed by a first address conversion part 5, and data is shifted and is written in the vertical display memory 7. Thereafter, data in the vertical display memory 7 is outputted by a display memory switching part 8, and the graphic rotated by 90 deg. is displayed on a CRT 9. Thus, the picture is quickly rotated at 90 deg. and is displayed on the CRT. |
