| 摘要 |
PURPOSE:To process pictures at a high speed by converting the picture data of the 1st picture element density read out of the 1st memory via a system bus into the picture data of the 2nd picture element density and at the same time delivering the picture data to the 2nd memory without passing through the system bus. CONSTITUTION:The picutre data of high density is read out of a picture memory 34 via a system bus 30 and supplied to a density converting circuit 130 via a DMA controller 120 for each data equivalent to one line. The picture density is converted by performing an OR operation for each data on adjacent two picture elements. Then the controller 120 gives a request to a display controller 140 to write data to a display buffer memory 150. Therefore the picuture data equivalent to one line and stored in the circuit 130 after conversion of density is read out and stored to a display buffer memory 150. This picture data is read out every block and transferred to a shift register 160. Then this data is parallel- serial converted and delivered to a CRT display 38 in the form of the serial picture element data. |
