Path: utzoo!attcan!uunet!husc6!bloom-beacon!gatech!ncsuvx!mcnc!duke!romeo!ndd
From: ndd@romeo.cs.duke.edu (Ned D. Danieley)
Newsgroups: comp.windows.x
Subject: what's wrong with this program? (X11)
Keywords: X11
Message-ID: <12080@duke.cs.duke.edu>
Date: 22 Jul 88 15:21:11 GMT
Sender: news@duke.cs.duke.edu
Lines: 92

The following program behaves strangely when run on a Sun 3/280
under SunOs 3.5, X11R2, and twm. It is supposed to print the text
'hi there' and draw a line. It always draws the line, but sometimes
does not draw the text.  It seems to always work correctly without
twm running. I realize that I'm not doing anything with events, but
my application needs to be able to put up text and graphics before
worrying about events.

Another interesting problem with this program is that if I move the
call to XMapWindow down below the XLoadQueryFont, I don't get the text
or the line.

Any help with this problem would be appreciated; I've got a bunch of
X10 code to convert, so I need to understand this.

Ned Danieley (ndd@sunbar.mc.duke.edu)
Basic Arrhythmia Laboratory
Box 3140, Duke University Medical Center
Durham, NC  27710
(919) 684-6807 or 684-6942

--------------------------------------------------------------------
#include <stdio.h>
#include "X11/Intrinsic.h"

#define	BORDER		4

Window pw, rootw;

char *disp = NULL;
Display *dpy;

main(argc, argv)
int argc;
char *argv[];
{
register int i;
int screen, width, height;
Widget makemenu();
XFontStruct *font;
GC gc;
XGCValues gcv;
unsigned long black_pixel;		/* pixel value for black */
unsigned long white_pixel;		/* pixel value for white */


	if ((dpy = XOpenDisplay(disp)) == NULL) {
                fprintf(stderr, "%s: Can't open display '%s'\n", argv[0],
                        DisplayString(dpy));
                exit(1);
		}

/* create parent window */
	rootw = DefaultRootWindow(dpy);
	screen = DefaultScreen(dpy);
	width = DisplayWidth(dpy, screen);
	height = DisplayHeight(dpy, screen);
	white_pixel = WhitePixel(dpy, screen);
	black_pixel = BlackPixel(dpy, screen);

        pw = XCreateSimpleWindow(dpy, rootw, 0, 0,
		width / 4, height / 4,
		BORDER, white_pixel, black_pixel);

	XMapWindow(dpy, pw);
	if (!(font = XLoadQueryFont(dpy, "vg-25"))) {
		fprintf(stderr, "couldn't open %s\n", "vg-25");
		exit(1);
		}

/* put XMapWindow here and nothing is draw in the window */

	gcv.foreground = white_pixel;
	gcv.background = black_pixel;
	gcv.font = font->fid;
	gc = XCreateGC(dpy, pw, GCForeground | GCBackground | GCFont, &gcv);

        XDrawString(dpy, pw, gc, 100, 100, "hi there ", 9);

	for (i = 0; i < 100; i++) {
		XDrawPoint(dpy, pw, gc, 100 + i, 100 + i);
		XDrawPoint(dpy, pw, gc, 101 + i, 100 + i);
		}

	XFlush(dpy);

	for ( ;; ) {
		XEvent ev;

		if (XPending(dpy)) XNextEvent(dpy, &ev);
		}
}