> > the idea was not to use the original drawable but to have the preview
> > create a scaled version of the selected area and expose it to the
> > plug-in as if it was a drawable. This will need some hacks in the
> > proxy drawable code in libgimp but I think it could be done.
> Oh, ok. That's a good idea.  I parsed that sentence as meaing that the 
> same function could be used to preview code in the preview widget or in 
> the image window (like the jpeg plugin preview hack). Having multiple 
> simultaneous previews in the same image window just wouldn't work.
> Rockwalrus

The idea was also to do kind of what de jpeg plug-in does, and this will not
involve any further locking, altough the behaviour seems a little strange to
the user..

The way the jpeg code does it is by creating a new temporary layer on top
of the layer stack. The jpeg plug-in is itself responsible for creating and 
deleting this layer. 

The same goes for other plug-ins that should do the same (I've been playing
around with this a little).

I'll illustrate what happens with some layer stacks

save as jpeg
[ background | jpeg preview ]
adjust colors in yuv space
[ background | jpeg preview | yuv preview ]
adjust jpeg parameters
[ background | yuv preview | jpeg preview ]

The previews won't interfer with each other since they only read from the
original drawable. At the moment the jpeg plug-in doesn't bother about
setting the current active layer (I think),.. so the active layer changes
back and forth between the preview and the original.

The ability to run multiple plug-ins whilst drawing on the image,.. is kind of
a usability issue anyways,.. but using preview layers won't make it worse.


                        .~.    The mind is its own place,and in
http://hnb.sf.net/      /v\    itself can make a Heaven of Hell
http://hal9001.2y.net/ /(_)\   a Hell of Heaven.  - John Milton
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