| 摘要 |
PURPOSE: To display even a hatch pattern naturally and perform reducing operation fast by providing a pixel information change detecting means, a sampling position determining means, and a sampling means. CONSTITUTION: An X-directional DDA computer 5 calculates X-directional residues for every clock according to algorithm and outputs the sign Esx of the residues, and a Y-directional DDA computer 6 calculates Y-directional residues for every line by a DDA method and outputs the sign Esy of the residues. For reduction, pixels are copied from a source image to a destination image only when Esx and Esy are both 0. For the purpose, a destination image memory controller 4 writes a Pdata signal as pixel data of the source image in a destination image memory 2 when Esx and Esy are both 0, and updates the address of the memory 2. Consequently, an image generated by reducing the image in the source image memory 1 is stored in the memory 2. |
