Unit 'layers' Package
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SwapBitsRastPortClipRect

Swap bits between common bitmap and obscured ClipRect

Declaration

Source position: layers.pas line 115

procedure SwapBitsRastPortClipRect(

  rp: PRastPort;

  cr: PClipRect

);

Arguments

rp

  

pointer to rastport

cr

  

pointer to cliprect to swap bits with

Description

Support routine useful for those that need to do some operations not done by the layer library. Allows programmer to swap the contents of a small BitMap with a subsection of the display. This is accomplished without using extra memory. The bits in the display RastPort are exchanged with the bits in the ClipRect's BitMap.

Note: the ClipRect structures which the layer library allocates are actually a little bigger than those described in the graphics/clip.h include file. So be warned that it is not a good idea to have instances of cliprects in your code.

Attention

Because the blit operation started by this function is done asynchronously, it is imperative that a WaitBlit() be performed before releasing or using the processor to modify any of the associated structures.


Documentation generated on: 2021-07-30