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From: aim@corp.sun.COM (Amy)
Newsgroups: comp.windows.x
Subject: Re:  X window
Message-ID: <9011081937.AA17604@slotown.Corp.Sun.COM>
Date: 8 Nov 90 19:37:14 GMT
Sender: daemon@athena.mit.edu (Mr Background)
Organization: The Internet
Lines: 114


>>From xpert-mailer@expo.lcs.mit.edu Wed Nov  7 19:46:33 1990
>>Organization: New York State Office of General Services, Albany, NY.
>>Subject: X window
>>Sender: xpert-request@expo.lcs.mit.edu
>>To: xpert@expo.lcs.mit.edu
>>
>>
>>Hi,
>>  I've been working on OPEN LOOK GUI & TOOLKITS in trying to display a tif file
>>, bitmap file actually, to be a child widget on the scrolledwindow widget. The
>>displaying of image failed for unknown reason in which I suspect if the 
>>scrolledwindow widget does have the functionality to accommodate image. In 
>>addition to that, I also used one of the Xlib functions, XPutImage, to be an
>>alternative. XPutImage failed to display the image either and caused core dump.
>>If anyone does have the experience of dealing image displaying with OPEN LOOK
>>GUI & TOOLKITS, I'll appreciate that precious information. Thank you.
`
I'm not sure exactly how you are trying to accomplish the above, but,
the ScrolledWindow widget in the OpenLook Intrinsics Toolkit is designed to
provide scrolling capabilities for a WIDGET created as its child.  What
you are looking for is scrolling canvas functionality - the way you get that
is to create a ScrolledWindow and create a Stub widget as it's child.  The Stub
which allows you to attach your own expose handler using the resource XtNexpose -
and it's in this procedure that you want to do any drawing (hence, this is where
you'd load your image).  Below is a simple program whichs sets this up for you.

Hope this helps.
Regards,
Amy Moore
aim@sun.com

#include <X11/Intrinsic.h>
#include <X11/StringDefs.h>
#include <Xol/OpenLook.h>
#include <Xol/Stub.h>
#include <Xol/ScrolledWi.h>

/******************************************************************
 * CreateDrawableCanvas: function to create a widget which can
 * be used for rendering xlib graphics.
 * This function returns the handle to the created Stub widget.
 *****************************************************************/
 Widget
CreateDrawableCanvas(name,parent, width, height)
char *name;
Widget parent;
int width, height;
{
	Widget canvas;
	Arg arg[4];
	int n = 0;

	XtSetArg(arg[n], XtNwidth, 	(Dimension) width);	n++;
	XtSetArg(arg[n], XtNheight, 	(Dimension) height);	n++;

	canvas = XtCreateManagedWidget(name, stubWidgetClass, 
						parent, arg, n);

	return(canvas);
}
/*************************************************************************
 * exposeHandler: routine called on Exposure events on the Canvas(Stub).
 ************************************************************************/
void exposeHandler(w, xevent, region)
Widget w;
XEvent *xevent;
Region region;
{
	Display *display;
	GC gc;
	XGCValues gc_values;
	Window paint_win;
	
	display = XtDisplay(w);
	paint_win = XtWindow(w);

 	/*************************************************
 	* All xlib drawing routines would go here....
 	*************************************************/
}
/**********************************************************************/


main(argc, argv)
int argc;
char **argv;
{
	Widget toplevel, scrollwin, canvas;
	Arg arg[10];
	int n = 0;

	toplevel = OlInitialize(argv[0], "Canvas Test", NULL,
						0, &argc, argv);

	XtSetArg(arg[n], XtNviewHeight,	150);	n++;
	XtSetArg(arg[n], XtNviewWidth,	150);	n++;
	scrollwin = XtCreateManagedWidget("scroller", 
				scrolledWindowWidgetClass,
				toplevel,
				arg,
				n);

	/* Create canvas (Stub) and set its expose Method */
	canvas = CreateDrawableCanvas("canvas", scrollwin, 300, 300);
	XtSetArg(arg[0], XtNexpose, 	(void)exposeHandler);
	XtSetValues(canvas, arg, 1);


	XtRealizeWidget(toplevel);
	XtMainLoop();

}
/*******************************END EXAMPLE*************************/