NAME¶
vga_bitblt - copy pixmap on screen using an accelerator
SYNOPSIS¶
#include <vga.h>
void vga_bitblt(int srcaddr, int destaddr, int
w, int h, int pitch);
DESCRIPTION¶
Bitblit (copy rectangular area in video memory), addresses are offsets into
video memory (up to 2M). The
pitch is the logical width of the screen.
Height
h is in Pixels, Width
w is in
BYTES!
This is an old style function to access the accelerator of an SVGA card. Before
calling it you should check for availability of the function in the mode you
use with
vga_getmodeinfo(3).
For new applications you might be better of trying to use
vga_accel(3)
instead.
The old
vga_bitblt(3),
vga_blitwait(3),
vga_fillblt(3),
vga_hlinelistblt(3), and
vga_imageblt(3) interface was
originally designed for the Cirrus chipsets. Then Mach32 added support too but
has problems to resemble the unintuitive Cirrus interface. Then these new
ideas were reinjected and
vga_accel(3) was designed. Now Cirrus and
Chips & Technologies chipset give limited
vga_accel(3) support but
no longer this old style support. Mach32 is left to use the unintuitive Cirrus
interface. At some future point the functions might be added for Mach32 too
(which should be rather simple), so new applications should use the newer and
probably more efficient interface.
It would be fatal if the accelerator would be used while the console is switched
away. You should use
vga_lockvc(3) and
vga_unlockvc(3) to avoid
this, although good implementations of the accelerator functions (like Mach32)
will already ensure that.
The
testaccel(6) demo utilizes the old style accelerator functions.
SEE ALSO¶
svgalib(7),
vgagl(7),
libvga.config(5),
testaccel(6),
vga_accel(3),
vga_blitwait(3),
vga_fillblt(3),
vga_hlinelistblt(3),
vga_imageblt(3),
vga_getmodeinfo(3),
vga_lockvc(3),
vga_unlockvc(3)
AUTHOR¶
This manual page was edited by Michael Weller
<eowmob@exp-math.uni-essen.de>. The exact source of the referenced
function as well as of the original documentation is unknown.
It is very likely that both are at least to some extent are due to Harm
Hanemaayer <H.Hanemaayer@inter.nl.net>.
Occasionally this might be wrong. I hereby asked to be excused by the original
author and will happily accept any additions or corrections to this first
version of the svgalib manual.
