ado@elsie.UUCP (Arthur David Olson) (11/29/89)
Elsie is our Sun 3/280 running SunOS 4.0.3. If I log in to elsie from the
console of our SGI IRIS 4D/70G and try to drop pixels into an X window,
things go awry--in particular, only the low-order four bits of the pixels
being written seem to make it to the window.
I've attached a typescript showing the problem (the incorrect results are
marked with ">>>>"s).
If you can tell me what I'm doing wrong, I'd appreciate hearing from you by
electronic mail.
--
Arthur David Olson ado@alw.nih.gov ADO is a trademark of Ampex.
Script started on Thu Nov 16 14:16:02 1989
elsie$ cat try.c
#include <stdio.h>
#include <X11/Xlib.h>
#define WIDTH 20
#define HEIGHT 1
Display * display;
int screen_number;
Visual * visual;
Window root_window;
Window window;
GC default_gc;
XImage * ximage;
char data[WIDTH][HEIGHT];
main()
{
int x, y;
display = XOpenDisplay((char *) NULL);
if (display == 0)
abort();
root_window = DefaultRootWindow(display);
screen_number = XDefaultScreen(display);
visual = DefaultVisual(display, screen_number);
default_gc = DefaultGC(display, screen_number);
window = XCreateSimpleWindow(display, root_window, 300, 300,
WIDTH, HEIGHT, 2, 0, 1);
XMapWindow(display, window);
XSync(display, 0);
(void) printf("Tap RETURN when the window is in place.\n");
(void) getchar();
ximage = XCreateImage(display, visual, 8, ZPixmap,
0, (char *) data, WIDTH, HEIGHT, 8, 0);
if (ximage == 0)
abort();
for (x = 0; x < WIDTH; ++x)
for (y = 0; y < HEIGHT; ++y)
XPutPixel(ximage, x, y, x);
XPutImage(display, window, default_gc, ximage,
0, 0, 0, 0, WIDTH, HEIGHT);
ximage = XGetImage(display, window, 0, 0,
WIDTH, HEIGHT, (unsigned long) ~0, ZPixmap);
for (x = 0; x < WIDTH; ++x)
for (y = 0; y < HEIGHT; ++y)
(void) printf("data[%d][%d]\t%d\n", x, y,
XGetPixel(ximage, x, y));
return 0;
}
elsie$ cc -g try.c -lX11 -o try
elsie$ try
Tap RETURN when the window is in place.
data[0][0] 0
data[1][0] 1
data[2][0] 2
data[3][0] 3
data[4][0] 4
data[5][0] 5
data[6][0] 6
data[7][0] 7
data[8][0] 8
data[9][0] 9
data[10][0] 10
data[11][0] 11
data[12][0] 12
data[13][0] 13
data[14][0] 14
data[15][0] 15
>>>> data[16][0] 0
>>>> data[17][0] 1
>>>> data[18][0] 2
>>>> data[19][0] 3
elsie$ exit
script done on Thu Nov 16 14:16:47 1989