DrawFile_Render (changes)
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DrawFile
» SWI Calls
» DrawFile_Render
DrawFile_Render
(SWI &45540)
| Entry | |
|---|---|
| R0 | Flags |
| R1 | Pointer to drawfile block? |
| R2 | Length of block |
| R3 | Transformation matrix, or 0 to use identity |
| R4 | Pointer to clipping rectangle in OS units, or 0 for none |
| R5 | Flatness with which to render lines (if bit 2 of R0 set) |
| Exit | |
|---|---|
| R0 | Preserved |
| R1 | Preserved |
| R2 | Preserved |
| R3 | Preserved |
| R4 | Preserved |
| R5 | Preserved |
Flags
| Bit | Meaning if set |
|---|---|
| 0 | Render bounding boxes (as dotted red rectangles) |
| 1 | Do not render the objects themselves |
| 2 | Use R5 as flatness |
Use
The purpose of this call is to render a Draw DrawFile file to the screen.
Notes
This SWI renders a draw DrawFile file at a given screen position where that position is defined as screen position 0, 0 with the x- and y-translations as specified in the transformation matrix. Hence, to render a non-rotated 1:1 draw file at (x, y) (screen coordinates in OS units) the transformation matrix is :
| (1 << 16 | 0) |
| (0 | 1 << 16) |
| (256 * x | 256 * y) |
The clipping rectangle is typically a redraw rectangle returned by the Wimp on a redraw window request. If R4 = 0, then the whole draw file is rendered. If non-zero, only objects which intersect the clipping rectangle are rendered.
See also
Draw File Format?DrawFile format- DrawFile_BBox
- DrawFile_DeclareFonts
- Transformation matrix
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