On Sat, 25 Sep 1999, Richard Moore wrote:

> 
> 
> Espen Sand wrote:
> > 
> > On Fri, 24 Sep 1999, Richard Moore wrote:
> > > Espen Sand wrote:
> > > >
> > > > Every addition is nice. However one thing that I think is really needed by all
> > > > drawing applications is undo (and perhaps redo) support. Ok it is perhaps
> > > > a rather big task but it is a very valuable feature.  At least xpaint has
> > > > some undo functionality so perhaps you can borrow some code from there.
> > >
> > > I would suggest starting with something a little easier! How about
> > > improving the area selection/cut and paste code. I would also love
> > > to have a crop feature. There is certainly plently of room for
> > > improvement in kpaint, so do whatever you feel comfortable with.
> > >
> > > Rich.
> > 
> > Yes of course. It was just that this issue popped up when the words "kpaint" and
> > "development" were mentioned ;) As I said it is a big task and should not be
> > dealt with before one really knows the code and structure (inner workings) of
> > the program. In order to get this knowledge, implementing the features
> > mentioned above is a good method.
> 
> :-) I just wanted to make sure he didn't try this first. I certainly
> agree that undo/redo would be a great feature.

Well, the command pattern makes it somewhat simple (at least conceptually)
to add multilevel undo redo for an app.

This was the first thing I worked on for the kodeknight editor, and it
went fairly smooth. I have later changed some of the commands to do their
tasks smarter, but that is not necessary for a start.

If you want to look at working code, you can check out the KodeKnight
module, go to dir kk/servers/ked and look in cmd.* and editorcmd.* to see
an example. The code using the commands is mostly located in textwnd.cpp.
You will not (yet) be able to compile KK - I am working on this right now
- but this code is not to blame for this problem, and it should be working
quite smooth.

--

Bo Thorsen
gobo@imada.sdu.dk
Lahnsgade 31, st.
DK-5000 Odense C
Tlf: +45 66 11 83 85