Conference bulova::decw_jan-89_to_nov-90

/*
           <<< STAR::BULOVA$DISK:[NOTES$LIBRARY]DECWINDOWS.NOTE;1 >>>
                -< DECwindows Standard Programming Environment >-
================================================================================
Note 667.10                           CYCLE                             10 of 10
ENT::BURLEIGH "A simple desultory phillipic"        151 lines  29-JUL-1988 10:31
                        -< uwm-style input focus hack >-
--------------------------------------------------------------------------------

        The following heresy provides pointer-location-driven
        input focus. Seems to work for me, but hasn't been
        exhaustively tested. Compile and run as a detached
        process.

        Use at your own risk ;-]

        Dave
*/

/*

  autofocus.c: Crude hack to do uwm-style focus management.
               Author: (chooses to remain anonymous)

*/
#include <stdio.h>
#include <decw$include/Xlib.h>
#include <decw$include/Xutil.h>

#define forever           while(1)

static Window GetWMRoot();
static XWMHints *GetWMHints();  /* Recursive */
static int IgnoreDeadWindow();

main(argc,argv)
   unsigned int argc;
   char *argv[];
{
   Display *display;
   Window wmroot,current,*children,*child;
   XWMHints *wmhints;
   int nchildren,i;

   /* Open the default display */

   if (!(display = XOpenDisplay(NULL))) {
      fprintf(stderr,"Can't open display\n");
      exit(0);
   }

   /* Find the window manager's pseudo-root window & its children */

   wmroot = GetWMRoot(display,&children,&nchildren);
   XSelectInput(display,wmroot,SubstructureNotifyMask);

   /* Find out which children have set window manager hints */

   for (i = 0, child = children; i < nchildren; ++i, ++child) {
      if (wmhints = GetWMHints(display,*child,&current)) {
         XSelectInput(display,current,EnterWindowMask);
         XFree(wmhints);
      }
   }

   /* Ignore error when we try to set focus on a window which has died
      since we received the EnterWindow event */

   XSetErrorHandler(IgnoreDeadWindow);

   forever {
      XEvent event;
      XMapEvent *map = (XMapEvent *)&event;
      XEnterWindowEvent *enter = (XEnterWindowEvent *)&event;

      XNextEvent(display,&event);
      switch (event.type) {
         case MapNotify: if (wmhints = GetWMHints(display,
                                                  map->window,
                                                  &current)) {
                            XSelectInput(display,current,EnterWindowMask);
                            XFree(wmhints);
                         }
                         break;

         case EnterNotify: XSetInputFocus(display,enter->window,
                                          RevertToPointerRoot,CurrentTime);
      }
   }
}

static XWMHints *GetWMHints(display,window,app_window) /* Recursive */
   Display *display;
   Window window,*app_window;
{
   XWMHints *wmhints;

   if (wmhints = XGetWMHints(display,window)) {
      *app_window = window;
      return wmhints;
   }
   else {
      Window root,parent,*children,*child,current = window;
      int i,nchildren;

      XQueryTree(display,current,&root,&parent,&children,&nchildren);
      for (i = 0, child = children; i < nchildren; ++i, ++child) {
         if (wmhints = GetWMHints(display,*child,app_window))
            return wmhints;
      }
      return NULL;
   }
}

static Window GetWMRoot(display,children,nchildren)
   Display *display;
   Window **children;
   int *nchildren;
{
   Window window,root,parent,*child;
   XWMHints *wmhints;
   int x,y,width,height,bw,depth;
   register int i;

   window = RootWindow(display,DefaultScreen(display));
   XQueryTree(display,window,&root,&parent,children,nchildren);

   /* Find first full-screen child of root */

   for (i = 0, child = *children; i < *nchildren; ++i, ++child) {
      XGetGeometry(display,*child,&root,&x,&y,&width,&height,&bw,&depth);
      if (width == DisplayWidth(display,DefaultScreen(display)) &&
          height == DisplayHeight(display,DefaultScreen(display))) break;
   };

   /* Find first full-screen child of first full-screen child of root */

   window = *child;
   XQueryTree(display,window,&root,&parent,children,nchildren);
   for (i = 0, child = *children; i < *nchildren; ++i, ++child) {
      XGetGeometry(display,*child,&root,&x,&y,&width,&height,&bw,&depth);
      if (width == DisplayWidth(display,DefaultScreen(display)) &&
          height == DisplayHeight(display,DefaultScreen(display))) break;
   };

   /* Found window manager's pseudo-root; return it & its children */

   window = *child;
   XQueryTree(display,window,&root,&parent,children,nchildren);
   return window;
}

static int IgnoreDeadWindow(display,error)
   Display *display;
   XErrorEvent *error;
{
   if (error->request_code == 42)  /* Life, the Universe, & Everything */
      return;
   else XSetErrorHandler(NULL);
}

    An alternative would be to use MOTIF, which does this in a little
    more supported manner.  See the SUBWAY::MOTIF conference for kit
    locations and licensing requirements.

             Dave

Thanks for the help. I'll try them.

Tim...