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List:       kde-kimageshop
Subject:    Re: undo/redo
From:       Michael Koch <m_koch () bigfoot ! de>
Date:       1999-08-09 10:54:59
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Am Mon, 09 Aug 1999 schrieb Matthias Elter:
> Hi
> 
> I just saw Michaels commit on kde-cvs (hooks for undo/redo functions)
> and as I'm unsure how we should handle undo/redo I start a discussion
> here.
> 
> IMHO we should provide unlimited undo/redo. A possible mechanism I could
> think of is:
> 
> There are two different modifications:
> 
> - Modifications of image data: We have to make snapshots of modified
> areas per layer.
> We should keep the last few snapshots in memory (let the user adjust the
> max. memory that may be used for undo) and save older snapshots on disk.
>  
> - Other modifications that do not effect the image data (zoom in/out,
> ruler metric changes etc.): We just have to save the action that has
> been done.

IMHO this a wasting of memory and harddisk space.

An other solution could be, that the user can choose the undo depth in the
preferences dialog. All "older" undo commands are lost. The default value could
be "infinite" (Matthias solution).

I want to implement it in the KOffice way: with Commands that do it and can
undo it. Then we have Undo/Redo.

--
Michael Koch


KDE fan, enthusiast and developer

student of computer science at university of applied sciences of Darmstadt, Germany

koch@kde.org, m_koch@bigfoot.de, mkoch@mail.riednet.wh.tu-darmstadt.de
http://www.riednet.wh.tu-darmstadt.de/~mkoch

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