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List:       kde-devel
Subject:    Re: Undo functionality - best way to add it?
From:       "Troy Corbin Jr." <tcorbin () users ! sourceforge ! net>
Date:       2002-09-14 13:45:15
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On Saturday 14 September 2002 06:24 pm, Jason Wood wrote:
> Hi,
>
> In an application I am writing, I have just started thinking about how best
> to add multilevel undo functionality, and whilst I have a couple of ideas
> myself I will basically be feeling in the dark on this one. Does anyone
> know of any particularly good ways of implementing Undo, or any references
> on the subject? Is there any kind of Undo framework that I can use already
> built into KDE?

I think this depends on what kind of data you'll be 'undoing'. In my app I can 
keep a QValueList of my data, with a new entry for each change. The List 
holds the whole document for each entry because of how small the data itself 
is. If you're working with large images or text files, you may want to store 
only the changed area, and include instruction for your app to insert or 
remove the changed data as needed.
-- 
Troy Corbin Jr.
tcorbin@users.sf.net
http://knights.sf.net

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