Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!wsu-cs!vip
From: vip@wsu-cs.uucp (Virtual Interactive Programming)
Newsgroups: comp.windows.x
Subject: XCopyArea Problem With UWS 2.0
Keywords: XCopyArea
Message-ID: <758@wsu-cs.uucp>
Date: 23 Jun 89 17:53:03 GMT
Organization: Wayne State University, Detroit, MI
Lines: 59


In the process of upgrading from ULTRIX 2.2 to UWS 2.0 running 
DECwindows, we have encountered a problem with the X11 command XCopyArea
when it is used to copy a portion of the root window into a pixmap.

This problem doesn't occur on our microVAX GPX running ULTRIX 2.2.
Any suggestions can be e-mailed to vip@zeus.cs.wayne.edu.
On the next page is a 30-line program which demonstrates the problem.

Thank you for your help. 

/*  --  The following code demonstrates the problem we are having
    --  with XCopyArea with UWS 2.0.  Two carriage returns were added
    --  to separate the executions of XCopyArea.
*/
#include <stdio.h>
#include <X11/Xlib.h>
Display	  *dpy;      
GC	   gc; 
Pixmap     pix;      
Drawable   d;
XGCValues  values;

main()
{
  if ((dpy = XOpenDisplay("")) == 0)
  { printf("Cannot Open Display\n"); exit (1); }

  /*  --  When d is assigned to a window id created by our program,
      --  then this code works.
      --  The problem occurs when d is assigned the RootWindow.
  */
  d = RootWindow(dpy, DefaultScreen(dpy));

  if ((pix = XCreatePixmap (dpy, d, 100, 100, 
       DefaultDepth(dpy,DefaultScreen(dpy))))==0) printf("Can't Create pix\n");
  gc   = DefaultGC(dpy,  DefaultScreen(dpy));

  /* -- This is probably needed to copy from any windows on top of the
     -- Rootwindow(we tried it without it, it also fails)
   */ 
  XSetSubwindowMode( dpy, gc, IncludeInferiors );
  XFlush(dpy);

  /* -- Store screen area to pixmap
   */
  if(XCopyArea(dpy,d,pix,gc,0,0,100,100,0,0) == 0) printf("Root copy error\n");
  else printf("Root window copied to Pixmap.\n");
  XFlush(dpy);
  getchar();

  /* -- Put previously copied area back to the Rootwindow, at the same location
     -- (on our machine it throws garbage on the screen).
   */
  if(XCopyArea(dpy,pix,d,gc,0,0,100,100,0,0)==0) printf("Pix copy error\n");
  else printf("Pixmap copied to Root window.\n");
  XFlush(dpy);
  getchar();
}