Why does a "Save" screw up the "scroll" settings?

[Ray Bennett]

Hi Kurt,

I'm a relatively green Revolutionary, but am pretty "long in the tooth" 
in HyperCard (alas, since abandoned because I need to build software I 
can sell!).  This is a lengthy reply, but hopefully will either help us 
both or get someone else to jump in the thread.

Anyway, I've been futzing around with this scrolling situation a little 
more today.  Here are the specifics and below is a scrollbar handler 
for the scrollbar I used on the card.   I won't include the card here 
only because what I'm doing is somewhat proprietary.

The background (large group with background behavior set to "true") 
contains lots of graphics (mostly lines) and a few fields.  The height 
property of this group is 1724.  The top of this group is at -10 (i 
think this doesn't mean a lot, until you start printing stuff, then you 
need to pay attention to it).

There is another group on the card with lots of fields (170) whose 
values change on each card; it is 1661 high.  Its top is at 10  (the 
-10, 10 reflects the positioning needed for the graphics to properly 
layer under the active fields - I'm just too lazy to go back and fix 
it).

My card window is set (by the preopencard handler) to 695w x 880h.   I 
use a scrollbar control (named "rbscrollbar") on the left hand side of 
the card.  I make it invisible when I print the card, and visible when 
I'm done printing.  I have two handlers for printing the card - one for 
the top half, one for the bottom half.   Getting things to print 
successfully  was a non-trivial exercise, but based on a couple of 
Sarah's responses to previous printing questions, I finally figured it 
out.  (you have to dork around with the "into" printrect and probably 
have to lie about your left (in portrait) or top (in landscape) 
starting point.  {if these would be helpful to you, shoot me an email 
and I'll send them on}

I'd originally had handlers for most of the scrollbar messages, but 
realized that for my purposes, the scrollbarDrag message was adequate, 
and is always sent when there weren't any handlers for the others 
(scrollbarLineInc, scrollbarLineDec,...PageInc,...PageDec).

So, with that lengthy introduction, here is the little bit of scrollbar 
code.  It works perfectly.  The only problem I ever have is when I 
"save".  If I'm not at the top, I get basically graphical soup on my 
screen (until, of course, I move the scrollbar a touch - that fixes 
everything).

--The handler for scrollbar "rbscrollbar"
on scrollbarDrag newPosition
   -- startvalue is set to 0
   -- endvalue is set to 1300, note, even though the card is higher, 
this is all the "scroll" we need
   put newPosition into myNewPosition --serves no purpose now, I used to 
manipulate it.
   set the scroll of group "32ManBackground" to myNewPosition  --the bg 
group
   set the scroll of group "32_Normal_ActiveGroup" to myNewPosition 
--the "active" group
   set the top of scrollbar "rbscrollbar" to 0 -- probably no longer 
necessary, but i haven't tried without it.
   --
   if the thumbPosition of me is 0 then
     set the top of bg "32_Normal_ActiveGroup" to 10
     set the top of bg "32ManBackground" to -10
   end if
   -- these little beauties allow you to maintain the same scroll height 
on every card with the same bg
   set the _32BackScroll of this stack to the scroll of group 
"32ManBackground"
   set the _32ActiveScroll of this stack to the scroll of group 
"32_Normal_ActiveGroup"
   set the _32Thumb of this stack to the thumbPosition of scrollbar 
"rbscrollbar"
end scrollbarDrag

Hopefully, this long-winded-ness wasn't just a waste of everyone's time.
Ray

>

On Saturday, Jan 18, 2003, at 21:04 America/New_York, Kurt Kaufman 
wrote:

> I have also experienced strange goings-on (images whose position 
> suddenly jumps way off screen, sudden appearance of images as gray 
> rectangles, etc.), when I try to set up a window with scrolling 
> contents, though I'm *not* sure that I'm doing it correctly.  I'd be 
> interested in viewing the scripts of a project where this has been 
> successfully implemented.  -That would reassure me greatly!
>
> -Kurt
>
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