| 摘要 |
<p>PURPOSE:To display a picture element specifying symbol on the CRT of a display device by displaying the symbol on the CRT based on new picture element specifying symbol display position data in the display device. CONSTITUTION:Display position shift quantities DELTAX and DELTAY from a track ball 3 are added by an arithmetic processing part 2-4 to the last display position data X and Y held in a display position X holding register 2-5 and a display position Y holding register 2-6 to obtain new display position data X+DELTAX and Y+DELTAY. Those display position data X+DELTAY and Y+DELTAY are held in the display position X holding register 2-5 and display position Y holding register 2-6 and used for display position control over a picture element specifying symbol. When the arithmetic result is not within a display position permissible range, the arithmetic processing part 2-4 corrects the arithmetic result within the range and it is held in the registers 2-5 and 2-6.</p> |
