The link below uses a stack/list, but keeps it in memory (using a python list object) rather than writing to disk, so it is essentially the same thing in principle.
What I do like the idea of is to write to disk a separate 'backup' of the project file, perhaps using an autosave, so in the event of a crash or some other event that corrupts the project file, there is the option to restore back to one of the previous backup copies. But that's a different discussion I guess. But I must admit I'm no expert in things like this, I was just having a browse around to see how other pygtk apps handle undo :-) Cheers, Andy. 2010/1/21 francesco fantoni <[email protected]> > I was considering an approach similar to what is used in saving project > file: > using cPickle to create a "state" of project object (written to a > StringIO object), and inserted in a "history" stack/list. > This way we could have a undo/redo system, but a history system as well, > with the possibility to go back to any previous state of the working > session, and besides it would use a rather simple trick, with parts of > code already implemented. > History stack size can be limited to a certain number of stages with > user preferences system, or set to a reasonable hardcoded value. > With some work on set_project_modified() function that can trigger > project's state storing action... > The doubts I have are about memory usage (not a great issue I suppose > using binary protocol of cpickle and with a stack limited to e.g. 10 > passes) and speed (but cPickle and cStringIO are supposed to be rather > fast) > what do you think? > > francesco > > > Il giorno gio, 21/01/2010 alle 09.56 +0000, Andy Finch ha scritto: > > I haven't, I've been looking at other stuff. Although I have been > > looking around recently at how undo is done in python and came across > > this, which may help: > > > > http://www.nongnu.org/skencil/doc.html > > > > then follow the link to the undo documentation: > > > > http://www.nongnu.org/skencil/Doc/devguide-19.html#N1 > > > > Cheers, > > Andy. > > > > 2010/1/21 francesco fantoni <[email protected]> > > just to know, has someone already started working on the > > undo/history > > thing? > > > > best to all, > > francesco > > -- > > architetto Francesco Fantoni > > <HVA - Hermanitos Verdes Architetti> > > l.go san giacomo, 38 > > I-41100 modena (italia) > > tel.& fax. +39.059.217554 > > skype: hva_studio > > e.mail: [email protected] > > web: http://www.hv-a.com > > > > > > _______________________________________________ > > Mailing list: > > https://launchpad.net/~openshot.developers<https://launchpad.net/%7Eopenshot.developers> > > Post to : [email protected] > > Unsubscribe : > > https://launchpad.net/~openshot.developers<https://launchpad.net/%7Eopenshot.developers> > > More help : https://help.launchpad.net/ListHelp > > > -- > architetto Francesco Fantoni > <HVA - Hermanitos Verdes Architetti> > l.go san giacomo, 38 > I-41100 modena (italia) > tel.& fax. +39.059.217554 > skype: hva_studio > e.mail: [email protected] > web: http://www.hv-a.com > >
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