kml@sunset.cis.ufl.edu (Kevin Lahey) (04/26/89)
XPutImage appears to do some strange things when attempting to display monochrome images of the XYBitmap format on a display of depth greater than one. I'm running X11R3 with the Purdue speedups on various Sun3s running SunOS 4.0. I'm using twm, and trying to use the Athena widgets and the toolkit. I create a core widget inside a viewport widget. I set up to get Expose events. When I increase the size of the window or scroll it using the scroll bars, I get the expose event, which is the correct size, and I call XPutImage with the x, y, width and height values from the event. The image gets updated correctly, then a vertical white band is drawn on the image, generally near the edges of the image which have just been re-drawn. This only happens on the color screens; the program works perfectly on screens of depth one. It also works fine when I am refreshing the entire image; for instance, if I iconify the window, then de-iconify it, the image looks fine. It only screws up when it is trying to update only a part of the image. I have a work-around -- namely, I create a pixmap, XPutImage to the pixmap, and then do an XCopyPlane to the window. However, this doesn't strike me as elegant or clever; I should like to be able to use XPutImage to write to either color or monochrome screens. Thanks, Kevin -- Kevin Lahey UUCP: ...gatech!uflorida!beach.cis.ufl.edu!kml University of Florida, CIS Internet: kml@beach.cis.ufl.edu Whenever you find that you are on the side of the majority, it is time to reform. -- Mark Twain
rws@EXPO.LCS.MIT.EDU (04/26/89)
The image gets updated correctly, then a vertical white band is drawn on
the image, generally near the edges of the image which have just been
re-drawn.
You are almost certainly going to have to post a simple complete program to
demonstrate the problem, either to xbugs or xpert. There's seldom any better
way to understand what's going on.kml@MANATEE.CIS.UFL.EDU (Kevin Lahey) (04/27/89)
/*
* A sample program to demonstrate my XPutImage problems. This program is
* written using Xt, but I got the same sort of error when I used XPutImage
* with just strictly X programming; i.e., I don't think it is a
* toolkit problem.
*
* The problem: the program has no trouble displaying on a monochrome screen,
* but on a color screen, I get strange results: the image is displayed
* correctly, completely, but as soon as it is displayed, a vertical white
* band is drawn on the image. This doesn't happen every time, but mostly
* when I change the horizontal dimensions of the window, either with the
* scroll bars or by changing the size of the window from the window manager.
*
* I'm running SunOS 4.0 on Sun3s and X11R3 with Purdue speedups.
* I tried to make this example program minimalistic while still
* retaining the same behavior as my program. With luck, I just missed
* something subtle, and this isn't an X problem, although the program xim
* hinted at this problem in the README and xviewsun contains a workaround,
* but no comments.
*
* I appreciate mailed as well as posted responces:
* Kevin Lahey UUCP: ...gatech!uflorida!beach.cis.ufl.edu!kml
* University of Florida, CIS Internet: kml@beach.cis.ufl.edu
*/
#include <X11/Intrinsic.h>
#include <X11/StringDefs.h>
#include <X11/Shell.h>
#include <X11/Core.h>
#include <X11/Viewport.h>
void event_proc ();
Display *display;
Widget shell,
view,
canvas;
XImage *image;
main (argc, argv)
int argc;
char **argv;
{
int width = 400, height = 500;
XWindowAttributes window_attributes;
XtAppContext app_context;
Arg arg_list [4];
XtSetArg(arg_list [0], XtNwidth, 200);
XtSetArg(arg_list [1], XtNheight, 200);
XtSetArg(arg_list [2], XtNallowVert, True);
XtSetArg(arg_list [3], XtNallowHoriz, True);
XtToolkitInitialize ();
app_context = XtCreateApplicationContext ();
display = XtOpenDisplay (app_context, NULL, "Sample", "xdemo",
NULL, 0, &argc, argv);
shell = XtAppCreateShell ("Sample", "xdemo",
applicationShellWidgetClass,
display, NULL, 0);
view = XtCreateManagedWidget ("view", viewportWidgetClass,
shell, arg_list, 4);
XtSetArg(arg_list [0], XtNwidth, width);
XtSetArg(arg_list [1], XtNheight, height);
canvas = XtCreateManagedWidget ("canvas", widgetClass,
view, arg_list, 2);
XtAddEventHandler (canvas, ExposureMask, False, event_proc, 0);
XtRealizeWidget (shell);
create_image (width, height);
XtAppMainLoop (app_context);
}
/*
* Create a quick and dirty sample image for display.
*/
create_image (width, height)
int width, height;
{
int i,
bytes_wide;
char *data;
data = (char *) malloc (width * height);
for (i = 0; i < width / 8; i++)
data [i] = 204;
for (i = 0; i < width / 8; i++)
data [i + width / 8] = 51;
for (i = 0; i < height / 2; i++)
bcopy (data, data + i * width / 4, width / 4);
image = XCreateImage (display,
XDefaultVisualOfScreen(XtScreen(canvas)),
1, XYBitmap, 0, data, width, height,
8, width / 8);
}
/*
* Handle the exposure event.
*/
void
event_proc (w, client_data, event)
Widget w;
caddr_t client_data;
XExposeEvent *event;
{
if (event->type == Expose) {
printf ("At X = %d Y = %d width = %d height = %d\n",
event->x, event->y, event->width, event->height);
XPutImage (display, XtWindow(w),
XDefaultGCOfScreen (XtScreen(canvas)),
image, event->x, event->y, event->x, event->y,
event->width, event->height);
}
}