Re: [wxhaskell-users] problem with scrolledWindow

[Daan L. <daa...@xs...>]

Hi David,

> The refit function is definitely a nice addition, but I've run into
> difficulties again in not been able to figure out how to get my scrolled
> window working when it contains widgets (in a layout) that resize
> themselves and then call refit.  When they do this, the scrolled window
> gets resized to be big enough to contain the widgets, and won't let the
> user make it any smaller.  I'm not sure what the problem here is.  The
> layout should be determining the virtualSize of the scrolled window, not
> its actual size as it seems to be doing.

It is the correct behaviour for "refit" -- just not the behaviour that
you want :-) I think we need a special refit operation that does re-layout
the child widgets, but increases/decreases the "virtualSize" of a scrolled
window instead of its clientSize.

I am kind of busy with other things but I hope to look into it
somewhere this week, but if you feel like hacking, I have
added some implementation hints to the end of this mail.

> Is there some trick I need to know in order to get a scrolledWindow with
> scrollbars?

Use "virtualSize" to set the scrolling area. Use "scrollRate" to set the
speed of the scrollbars.

> Totally unrelated:
>
> It seems that wxhaskell doesn't compile with ghc 6.2 because parsec has
> moved into its own package.

I heard about that, however, I have decided not to support 'unreleased' ghc
versions actively. For now, you can probably just add

> HCFLAGS += -package parsec

to the makefile to get things working.

All the best,
  Daan.


---------------------------------
hints for implementing refitVirtual
---------------------------------

In WXCore/Layout.hs are the following functions:

windowRefitMinimal and windowReLayoutMinimal:

windowRefitMinimal just gets the parent window and calls relayout:

  windowReFitMinimal :: Window a -> IO ()
  windowReFitMinimal w
    = do p <- windowGetFrameParent w
         windowReLayout p

windowRelayout gets the sizer of a window and calls "windowFit"
to re-layout the child widgets.

  windowReLayoutMinimal w
    = do windowLayout w
         szr <- windowGetSizer w
         when (not (objectIsNull szr)) (sizerSetSizeHints szr w)
         windowFit w

At the end, the new clientSize of a window is set.
For a "windowReLayoutVirtual", one probably doesn't want
to call "windowFit" but set the virtual size of a window
instead??