tr@thumper.UUCP (03/28/87)
[]
I am cross-posting this to comp.sys.ibm.pc, mod.graphics and
comp.graphics.
I am having a problem with the HALO graphics function package.
My system includes:
IBM PC/AT
JRAM card with 2 MB memory; 512 KB is devoted to DOS
Talltree's JRAM and JLASER device driver software,
version 3.8
Canon LBP8 laser printer
IBM EGA card with 256 KB memory
Lattice C compiler version 3.1 using large memory model
IBM DOS version 3.20 (the disk says version 3.21)
Version 2.26b of the file HALOIBME.DEV
Version 2.26 of the rest of Halo for Lattice C version 3.
The problem is that I try to use two separate video pages of EGA
memory and the package does not seem to support this, regardless
of what the manual and the tech support person claim. Calls to
display page 1 result in displaying the same old page. These
pages are said to be numbered from 1 to 2 by the tech support
person, not 0 to 1. I have tried using what the she said but the
enclosed program uses 0 and 1. Calls to inqscreen and inqpage
sometimes result in numbers such as 300. They don't seem to be
reproducible. Yes, I know enough to pass addresses of values to
Halo functions, not the values. Halo functions work this way.
I want to be able to display something on the inactive page, then
swap that page into the active screen memory. This would make
for fast screen updates. Many commercial programs have succeeded
in doing this. Is the Halo package at fault or is it my code or
configuration?
The code below displays two boxes on the screen at the same time!
They should instead swap between keystrokes.
#include <stdio.h>
main()
{
int color, x1, y1, x2, y2;
int pri_scr = 0, alt_scr = 1, pri_dis = 0, alt_dis = 1;
int c, i;
tr_initgr(); /* This just calls the initgraphics routine. */
x1 = 10, y1 = 10, x2 = 100, y2 = 100;
color = 2;
setscreen(&pri_scr);
display(&pri_dis);
setcolor(&color);
bar(&x1, &y1, &x2, &y2);
setscreen(&alt_scr);
color = 4;
x1 = 100, y1 = 100, x2 = 300, y2 = 300;
setcolor(&color);
bar(&x1, &y1, &x2, &y2);
display(&alt_dis);
for (i = 0; i < 8; i++) {
c = getch();
display(&pri_dis);
c = getch();
display(&alt_dis);
}
tr_closegraphics(); /* This just calls the closegraphics routine. */
}
Tom Reingold
INTERNET: tr@bellcore.com
--------
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--
Tom Reingold
Internet: tr@bellcore.com
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--
Tom Reingold
Internet: tr@bellcore.com
Uucp: ..!allegra!ulysses!faline!flash!tr