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 QuickSCREEN Details Example Contents Index |
| ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ |
| PEN Statements Details |
| |
| Syntax |
| PEN ON |
| PEN OFF |
| PEN STOP |
| |
| The PEN ON statement enables lightpen-event trapping by using an ON PEN |
| statement. The pen is initially off. A lightpen event occurs whenever the |
| lightpen is activated by pressing the tip to the screen or pressing the |
| touch ring. A PEN ON statement must be executed before any read-pen function |
| calls. If a read-pen function is called when the pen is off, an error |
| message results that reads "Illegal function call." |
| |
| The PEN OFF statement disables lightpen event trapping. The PEN STOP |
| statement suspends lightpen event trapping; a pen event is remembered |
| and trapped as soon as event trapping is enabled. |
| |
| To speed program execution, the pen should be turned off by using a PEN OFF |
| statement when pen trapping is not needed. |
| |
| Note: The lightpen requires an IBM Color Graphics Adapter. |
