Mail Archives: djgpp/1994/04/05/13:30:25
I am trying, unsuccessfully, to use the graphics library that comes
with djgpp. I expected the following trivial program to draw a single red
line. The go32 environment variable is undefined. I expected that I
would use the default VGA driver for now. It is compiled and run with:
gcc graph.c -lgr
go32 a.out
#include <graphics.h>
void main () {
/* Trivial Test Program To Draw One Red Line */
int red;
GrSetMode(GR_default_graphics,800,600);
red = GrAllocColor(255,0,0);
GrLine(60,60,200,400,red);
/* Try to restore text mode before exiting */
GrSetMode(GR_80_25_text,80,25);
}
My dos screen has a black background with white text. The only
time I get any output from this program, is if I run it after
running my elvis editor which leaves a blue background. My program then
turns the screen area that still has a blue background to white but
does not draw a line. Thereafter, elvis comes up with a white background
and its white text is invisible until I issue a mode con lines=25
command.
Using libgrx instead of libgr produces no graphic output at all.
In case its relevant I am running DOS 6.2 on a 486DX2. I'm a
Fortran programmer just learning C so maybe I missing some thing obvious.
Any help will be appreciated.
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