[6487] in Athena Bugs
rt 7.2A: Xibm (apa16)
daemon@ATHENA.MIT.EDU (daemon@ATHENA.MIT.EDU)
Wed Nov 28 22:31:51 1990
Date: Wed, 28 Nov 90 22:31:32 -0500
From: "Jonathan I. Kamens" <jik@pit-manager.MIT.EDU>
To: bugs@ATHENA.MIT.EDU
System name: pit-manager
Type and version: RTPC-ROMPC 7.2A
Display type: apa16
megapel
What were you trying to do?
Use the XDrawImageString with a GC with the same background
and foreground color, drawing to a window on an APA16 monitor.
The problem below should display a line of black-on-white
text, and then an empty space, and then a line of
white-on-black text, and then a black bar.
What's wrong:
The APA16 device-dependent code barfs on a GC with the same
background and foreground colors. If I run the program
included below, the second line displayed is white-on-black
text instead of blank space, and the fourth line displayed is
black-on-white text instead of a black bar. The background
component of the GC is being misinterpreted, apparently.
What should have happened:
The program should have behaved as described in the "What were
you trying to do?" rather than as it actually behaved.
Please describe any relevant documentation references:
Note that if I run the server with -nohdwr, this problem does
not manifest itself. Note, further, that it does not manifest
itself on the megapel display, the VAXstation 3100 standard
display, or the DECstation 3100 standard display.
jik
*************************
#include <X11/Xlib.h>
#include <X11/Xos.h>
main()
{
Display *display;
GC testGC;
XGCValues GCvalues;
Window window;
int screen;
unsigned long black, white;
display = XOpenDisplay(0);
screen = DefaultScreen(display);
black = BlackPixel(display, screen);
white = WhitePixel(display, screen);
window = XCreateSimpleWindow(display, RootWindow(display, screen),
0, 0, (unsigned) 100, (unsigned) 250,
(unsigned) 1, black, white);
XSetWindowBackground(display, window, white);
XMapWindow(display, window);
XFlush(display);
sleep(5);
GCvalues.foreground = black;
GCvalues.background = white;
GCvalues.font = XLoadFont(display, "fixed");
testGC = XCreateGC(display, window,
GCForeground|GCBackground|GCFont,
&GCvalues);
XDrawImageString(display, window, testGC, 0, 50,
"black on white", strlen("black on white"));
XSetForeground(display, testGC, white);
XDrawImageString(display, window, testGC, 0, 100,
"white on white", strlen("white on white"));
XSetBackground(display, testGC, black);
XDrawImageString(display, window, testGC, 0, 150,
"white on black", strlen("white on black"));
XSetForeground(display, testGC, black);
XDrawImageString(display, window, testGC, 0, 200,
"black on black", strlen("black on black"));
XFlush(display);
sleep(30);
exit(0);
}
