[comp.windows.open-look] XVIEW SCROLLBAR question

jane@Unify.Com (06/21/91)

Anybody out there likes to tell me what happen with the XVIEW SCROLLBAR
problem that I am running into ?
 
The question is after I created a scrollbar and installed a callback routine
in the scrollbar(with attribute SCROLLBAR_NORMALIZE_PROC). Inside of the 
callback routine, I use xv_get(scrollbar_name, SCROLLBAR_VIEW_START) to 
get the value of SCROLLBAR_VIEW_START(in the mean time, I scroll the 
scrollbar), then I expect the SCROLLBAR_VIEW_START should not be 0
(because I am scrolling the bar), but I always get 0. Again, My 
question is why I can't get SCROLLBAR_VIEW_START value correctly? 
Is there any tricks involved in addition to the way I did ?
Is this a xview bug? are there any workaround ? 
(My scrolled object is a pixmap not a text file) 

	scrollbar = (Scrollbar)xv_create(canvas, SCROLLBAR,
		     SCROLLBAR_DIRECTION, SCROLLBAR_VERTICAL,
		     SCROLLBAR_PIXELS_PER_UNIT, 14,
		     SCROLLBAR_OBJECT_LENGTH, 71,
		     SCROLLBAR_VIEW_LENGTH, 17,
		     SCROLLBAR_PAGE_LENGTH, 17,
		     SCROLLBAR_NORMALIZE_PROC, monitor_scroll,
		     NULL);

monitor_scroll()
{
        int     view_start, last_view_start;
        
	   /* why view_start and last_view_start are always 0 ?*/ 
           view_start = (int) xv_get(scrollbar, SCROLLBAR_VIEW_START);
           last_view_start = (int)xv_get(scrollbar,
                                SCROLLBAR_LAST_VIEW_START);
}


Thanks,
Jane Huang    UUCP: uunet!natadm!jane
	      Network Application Technology

harling@pictel.uucp (Dan Harling) (06/25/91)

In article <jzhs7t5@openlook.Unify.Com> <uunet!uunet!natadm!jane@Unify.Com> Jane Huang writes:
>
>Anybody out there likes to tell me what happen with the XVIEW SCROLLBAR
>problem that I am running into ?
> 
>	scrollbar = (Scrollbar)xv_create(canvas, SCROLLBAR,
>		     SCROLLBAR_DIRECTION, SCROLLBAR_VERTICAL,
>		     SCROLLBAR_PIXELS_PER_UNIT, 14,
>		     SCROLLBAR_OBJECT_LENGTH, 71,
>		     SCROLLBAR_VIEW_LENGTH, 17,
>		     SCROLLBAR_PAGE_LENGTH, 17,
>		     SCROLLBAR_NORMALIZE_PROC, monitor_scroll,
		     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>		     NULL);
>
>monitor_scroll()
>{
>        int     view_start, last_view_start;
>        
>	   /* why view_start and last_view_start are always 0 ?*/ 
>           view_start = (int) xv_get(scrollbar, SCROLLBAR_VIEW_START);
>           last_view_start = (int)xv_get(scrollbar,
>                                SCROLLBAR_LAST_VIEW_START);
>}

What parameters and return value are the NORMALIZE_PROC supposed to
accept and return?  I know (by experimentation) that the first
parameter is a handle to the scrollbar.  The XView manual mentions the
SCROLLBAR_NORMALIZE_PROC argument at the end of the chapter on
scrollbars, but it is not documented anywhere else.


>Jane Huang    UUCP: uunet!natadm!jane

______________________________________________________________________
Daniel A. Harling					PictureTel, Inc.
Rockport, MA						Peabody, MA

	Opinions expressed herein are not necessarily those of
	PictureTel, Inc.; they are MINE, ALL MINE!  (So there.)
                                   ----  === ====