[Implemented] Undo command

[hv_francesco]

I have a first working proof-of-concept of a Undo/history system, but it's still buggy and unstable, and besides I'm not sure it's the best way to go.
It has the advantage that it doesn't need too many changes in existing code, as it tries to reshape a bit and use parts of code that are already there.
The down side is that it uses a rather "rough" concept, saving states of the project object in a stack serialized with cPickle, so restoring the previous state is not as fast as light.
I'm sure it can be done a lot better than this, so I hope that someone more experienced than I am can review my code and see if it is worth working on it or if it is totally dumb.

the branch is this:
lp:~francesco-hermanitosverdes/openshot/francesco_undo_redo_test

best regards to everyone
francesco

[Cenwen]

Thanks for your work francesco. I have download your branches yesterday night but i have not yet tested this is. But for this is who have the icon effect is working well. Okay personnaly, i don't like the icon, but it's my personnal view. In all cases, you have done a great work and i have not find a bug? But it was only a test.
Good work.

[hv_francesco]

Thank you. I put on a super-small screencast to show the first attempt to the undo stuff, I really hope I'm not pushing things in the wrong direction, and, as you can see, there are quite a lot of things to tweak and fix yet.

[Cenwen]

okay very nice. That's look fine.
Could you create a icon but i don't know where in the timeline icon bar or in the menu icon? Where is the most easy for the user ?
If we are all like you, Openshot will grown like a ........................TGV.

[hv_francesco]

I'm making some testing on a more complex project file, with a crowded timeline, because one of the problems of this approach is that, as long as the timeline grows more complex and the project more crowded, I suppose serialization-deserialization can take longer (not sure though).
It turns out that serialization is light-fast, and de-serialization/restoring of a previous state, seems to get a bit slower, but not much.
In my opinion cPickle is fast enough to handle this without problems, and the project restoring alghoritm can probably be optimized, but It is already better than I had feared.

[hv_francesco]

added more events to history tracking system, and a History panel in main window as in following screenshot:

history_panel.png (94.92 KiB) Viewed 691 times

[gnowak]

Great the undo command is what I miss the most.

How can I help?

[Cenwen]

She is included in the version 1.1.0 with an history (undo/rendo) and it will be soon. Stay tuned.

[gnowak]

Sweeet!!

[Madspyman]

Version 1.1.0-alpha2 is in Ubuntu Lucid alpha3 already, so I've tried the undo out and it's good.

[Cenwen]

Thanks for the feedback. We are in an intensive period of tests so all feedback is welcome.