Conference bulova::decw_jan-89_to_nov-90

/*
 * This example demonstrates problems with exposure event handling.  You can
 * specify two command line options: 'n', for no Xlib, which suppresses the
 * use of Xlib event handling routines to process the expose events, and
 * 'w', for window widget, which will create the work area as a window widget
 * rather than a dialog box widget.
 */

#include <decw$include:decwdwtwidgetprog.h>

void YesNoCancel();
void ExposureHandler();
void ButtonHandler();
void SetFlags();

static DwtCallback yesNoCancelCallback[] = {
   {YesNoCancel, NULL},
   {NULL, NULL}
};

static Widget top2;
static Display *display;

static int noXlib, useWindow;

main(argc, argv)
int argc;
char *argv[];
{
   Widget top1, wind1, wind2;
   Arg args[10];
   int i;


   if (argc > 1) SetFlags(argv[1]);
   if (argc > 2) SetFlags(argv[2]);

   top1 = XtInitialize("test1", "test", NULL, 0, &argc, argv);

   i = 0;
   XtSetArg(args[i], DwtNx, 200);                                    ++i;
   XtSetArg(args[i], DwtNy, 200);                                    ++i;
   XtSetValues(top1, args, i);

   i = 0;
   XtSetArg(args[i], DwtNwidth, 500);                                ++i;
   XtSetArg(args[i], DwtNheight, 400);                               ++i;

   if (useWindow) {
      wind1 = DwtWindowCreate(top1, "workarea", args, i);
   } else {
      wind1 = DwtDialogBoxCreate(top1, "workarea", args, i);
   }

   XtManageChild(wind1);
   XtAddEventHandler(wind1, ExposureMask, FALSE, ExposureHandler, NULL);

   display = XtDisplay(top1);

   i = 0;
   XtSetArg(args[i], DwtNx, 275);                                    ++i;
   XtSetArg(args[i], DwtNy, 250);                                    ++i;      
   top2 = XtAppCreateShell("test2", "test", applicationShellWidgetClass,
                           display, args, i);

   i = 0;
   XtSetArg(args[i], DwtNwidth, 500);                                ++i;
   XtSetArg(args[i], DwtNheight, 400);                               ++i;

   if (useWindow) {
      wind2 = DwtWindowCreate(top2, "workarea", args, i);
   } else {
      wind2 = DwtDialogBoxCreate(top2, "workarea", args, i);
   }

   XtManageChild(wind2);
   XtAddEventHandler(wind2, ExposureMask, FALSE, ExposureHandler, NULL);
   XtAddEventHandler(wind2, ButtonPressMask, FALSE, ButtonHandler, NULL);

   XtRealizeWidget(top1);

   XtRealizeWidget(top2);

   XtMainLoop();
}

void
ExposureHandler(windowWidget, data, event)
Widget windowWidget;
caddr_t data;
XExposeEvent *event;
{
   Window window = XtWindow(windowWidget);
   XEvent nextEvent;

   printf("------------------------\n");
   printf("(%d, %d), %d X %d, count = %d\n", event->x, event->y,
                                             event->width, event->height, 
                                             event->count);
   if (!noXlib) {
      XFlush(display);
      while (XCheckTypedWindowEvent(display, window, Expose, &nextEvent)) {
         printf("(%d, %d), %d X %d, count = %d\n", nextEvent.xexpose.x,
                                                   nextEvent.xexpose.y,
                                                   nextEvent.xexpose.width,
                                                   nextEvent.xexpose.height,
                                                   nextEvent.xexpose.count);
      }
   }
}

void
ButtonHandler(window, data, event)
Widget window;
caddr_t data;
XExposeEvent *event;
{
   Widget caution;
   DwtCompString label;

   label = DwtLatin1String("Save work before quitting?");
   caution = DwtCautionBox(top2, "yesnocancel",
                           TRUE, 0, 0, DwtModal,
                           label, NULL,
                           NULL, NULL,
                           DwtYesButton, yesNoCancelCallback, NULL);
   
   XtManageChild(caution);
   XtFree(label);
}

void
YesNoCancel(cautionBox, tag, data)
Widget cautionBox;
Opaque tag;
DwtAnyCallbackStruct *data;
{
   XtDestroyWidget(cautionBox);
}

void
SetFlags(opt)
char *opt;
{
   noXlib |= (*opt == 'n');
   useWindow |= (*opt == 'w');
}

    
    Why do you say the regions overlap?  Can you give a specific example?
    
    						monty

If I have three windows as shown below:


	____________________________________________________________
	|___________________________________________________________|
	|							    |
     _____________________________________________________________________
    |_____________________________________________________________________|
    |									  |
    |									  |
    |			______________________________			  |
    |			|_____________________________|			  |
    |			|			      |			  |
    |			|			      |			  |
    |			|			      |			  |
		.
		.
		.

The top window is my window.  The second window is the FileView Window and 
the third is the Work In Progress window.  If the FileView window is iconified,
both the Fileview and WIP window will be get iconified.  There will be a 
series of expose events generated for the regions exposed by the FileView
window and for the WIP window.  However I've noticed that the regions I get
back overlap.  If you run the progrm in note .1 and use the FileView and WIP
window as described, you should get the same result. 


-Pratish Shah

	I have another problem with expose events using the same program
	in note .1.

	When this program is run, two windows are created.  Press MB1 in
	window test2.  Then bring window test1 to the front by pressing
	on the title bar.  Then bring window test2 to the front.  Now
	press any one of the options in the dialog box.  The exposed region
	is much larger then the size of the box.  

	However if you just press the mouse button on window test2 and then
	pick any of the options in the dialog box, the reported exposed
	area is correct.

	Is this a bug or something?

	Thanks in advance,
	-Pratish Shah

    
    I tried it and it looks like a bug (though one that may be fixed in a
    future release).  Go ahead and QAR it and include the source to
    expose.c.  Thanks.
    
    						monty