Topic       : TOS - The Operating System
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Version     : tos.hyp (December 19, 2008)
Subject     : Programmieren/Atari
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Compiled on : Atari
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View Ref-File7.11  Raster functions                                             TOS

This library contains functions for manipulating rectangular blocks of 
bits in memory. The following routines are available for this purpose:

 ∙ v_get_pixel             Gets pixel status (set or cleared, colour)
 ∙ vq_hilite_color         Gets highlighting colour
 ∙ vq_max_color            Gets maximum colour value for an additive 
                           raster operation
 ∙ vq_min_color            Gets minimum colour value for a subtractive 
                           raster operation
 ∙ vq_weight_color         Gets weighting for the blend function
 ∙ vr_clip_rects_by_dst    Cuts destination rectangle with a clipping 
                           rectangle
 ∙ vr_clip_rects_by_src    Cuts source rectangle with a clipping 
                           rectangle
 ∙ vr_clip_rects32_by_dst  Cuts destination rectangle with a clipping 
                           rectangle (32-bit coordinates)
 ∙ vr_clip_rects32_by_src  Cuts source rectangle with a clipping 
                           rectangle (32-bit coordinates)
 ∙ vr_transfer_bits        Combines two bitmaps
 ∙ vr_trnfm                Transforms raster to device-specific 
                           formats and vice versa
 ∙ vro_cpyfm               Copies ('blits') a screen or memory block 
                           from one location to another (opaque)
 ∙ vrt_cpyfm               Copies ('blits') a screen or memory block 
                           from one location to another (transparent)
 ∙ vs_hilite_color         Sets highlighting colour
 ∙ vs_max_color            Sets maximum colour value for an additive 
                           raster operation
 ∙ vs_min_color            Sets minimum colour value for a subtractive 
                           raster operation
 ∙ vs_weight_color         Sets weighting for the blend function

Note: With these functions it is possible, in particular, to copy or 
move a screen area from one place to another; thanks to this one can 
obtain smooth scrolling in GEM programs, for instance.

See Also: Raster formats   Off-screen bitmaps   VDI workstations