.TH vga_imageblt 3 "27 July 1997" "Svgalib (>= 1.2.11)" "Svgalib User Manual"
.SH NAME
vga_imageblt \- copy a rectangular pixmap from system memory to video memory
.SH SYNOPSIS

.B "#include <vga.h>"

.BI "void vga_imageblt(void *" srcaddr ", int " destaddr ", int " w ", int " h ", int " pitch );

.SH DESCRIPTION
Write a rectangular pixmap from system memory to video memory.
.I destaddr
is an offset
into video memory (up to 2M). The
.I pitch
is the logical width of the screen. Height
.I h
is in Pixels, Width
.I w
is in
.BR BYTES !

It  fills the given box
with the data in memory area
.IR *srcaddr .
The memory  buffer must  contain the pixels in the same representation
as used in the vga memory, starting at the top left
corner, from left to right, and then, line by line,
from up  to  down,  without  any  gaps  and  interline
spaces.

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
.BR vga_getmodeinfo (3).

For new applications you might be better of trying to use
.BR vga_accel (3)
instead.

The old
.BR vga_bitblt (3),
.BR vga_blitwait (3),
.BR vga_fillblt (3),
.BR vga_hlinelistblt "(3), and "
.BR 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
.BR vga_accel (3)
was designed. Now Cirrus and Chips & Technologies chipset give limited 
.BR 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
.BR vga_lockvc (3)
and
.BR vga_unlockvc (3)
to avoid this, although good implementations of the accelerator functions (like Mach32)
will already ensure that.

The
.BR testaccel (6)
demo utilizes the old style accelerator functions.

.SH SEE ALSO

.BR svgalib (7),
.BR vgagl (7),
.BR libvga.config (5),
.BR testaccel (6),
.BR vga_accel (3),
.BR vga_bitblt (3),
.BR vga_blitwait (3),
.BR vga_fillblt (3),
.BR vga_hlinelistblt (3),
.BR vga_getmodeinfo (3),
.BR vga_lockvc (3),
.BR vga_unlockvc (3)

.SH 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.