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OS_Word 21_1
Programmer's Reference Manuals
» Part 15 – SWI Calls
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» OS_Word 21
» OS_Word 21,1
OS_Word 21,1
(SWI &07)
| Entry | |
|---|---|
| R0 | 21 (&15) |
| R1 | Pointer to 9-byte block |
| Exit | |
|---|---|
| R0 | Preserved |
| R1 | Preserved |
Use
The purpose of this call is to define the mouse coordinate bounding box, relative to the graphics origin.
Notes
This OS_Word defines the mouse coordinate bounding box, relative to the graphics origin. It is ignored if (left > right) or (top > bottom).
left = bottom = &8000, right = top = &7FFF gives an infinite box.
If outside the box, the current mouse position is homed to the nearest point inside. When read all buffered coordinates are similarly moved within the box. The box is set to the size of the screen on mode changes.