| 摘要 |
A visual (or video) display unit of the raster scan type has a symbol memory, where the dot patterns of the available symbols are stored, and a refresh memory, where information is stored which identifies the symbols present on the image in question and their positions on the image. An auxiliary memory constitutes a simplified reproduction of the refresh memory, for example with 1 bit for each word in the refresh memory. For each symbol on the image in question, the auxiliary memory defines, on the one hand, the element in the image which is written first during generation of the image, and on the other hand a definition element. In the place in the refresh memory, which corresponds to the position of the definition element in the image, there is stored a code which identifies the symbol. |
