On 10/20/07, Lars Clausen <[EMAIL PROTECTED]> wrote: > > > 1) The _Change struct in app/undo.h should have a facility to track > > side-effects. For example, when changing a text-object results in a > > resizing of the object, the resize should be recorded as a side-effect > > of the main text-related Change. > > Sounds necessary, given that many different objects use the same text > change object. Alternatively, they could come as a chain of changes, > since the prev/next links are right there.
Dunno what you mean by prev/next links ... but I suppose I'll see that when I take a better look at things related to undo and text objects. > > Also there is a hidden problem with the way the properties dialog > > tracks undo history. It records the previous state of _all_ known > > properties, whether or not they are changed. This can lead to > > scalability problems if we dare to think of huge groups of objects > > with a huge list of properties. > > That could take a fair amount of space, yes. We haven't seen it as a > problem I think mostly because mass change of properties has had the > problems of actually unifying all properties, and only now that you've > done the group properties update fixing are people likely to try > changing a large number of objects at the same time. I suppose you are hinting at this bug: http://bugzilla.gnome.org/show_bug.cgi?id=481979 Shape property dialog needs reordering This also becomes important, especially with support for properties of grouped objects. There are lots of smaller bugs related to the property dialog, which can have visible effect on the user experience. I already posted a patch on one, about the dialog popping up when you undo something. > > Also, this cannot handle side-effects > > to the object that do not involve properties. For example, changing > > the font of a text object changes its size, but this is not tracked by > > undo. > > Any changeable aspect of an object should be derivable from its > properties, otherwise it doesn't survive saving. I don't understand what you mean here. For example, I create a a flowchart object and save the file. Then I change the font size for the text in it and then save it again. What will not survive saving in this case? Also, I might choose to expand the object manually, which means this property of the object is not strictly derivable from the text content. > > This can only be fixed if the Undo/Redo infrastructure guarantees that > > side-effects are efficiently handled elsewhere. But the improvements > > required for Undo are quite extensive, and would require lots of > > planning as well as sufficient blessings from the gods of Dia. > > I bless the change as such, but I'm not sure it'd be a good idea to > start on it now. We have three major improvements in that should get > out to people, adding this would delay it yet further. Time has already > flown much faster on getting things fixed than I was hoping for. Yeah, I agree that we can't just start doing this right away. My posting is just an initial RFC to attract attention. I intend to just chip away on this problem in my spare time, with git-svn to help separately maintain my changes in a sane manner. I could keep that git repository publicly available with the hope that some kindred soul out there might decide to take a look and contribute. There could even be an SVN branch for "redoing undo", but I believe that's an unnecessary hassle for the maintainers. In the mean time, I would like to help with the current release, since my work on the group properties is as good as done now. Extending this work in terms of "selected objects" is in itself a big task, not considering the possibility of introducing "open groups". I don't mind working on whatever the maintainers think is desirable at this stage. So far I have been hopping all over the Dia code, hoping to find a fix for whatever bugs me the most. Also, a question about future plans, just out of curiosity ... is there a vision in place about 1.0, vague or detailed as it may be? There are loads and loads of small bugs and enhancement requests that can have a great impact on the user experience. Is there any plan to schedule a release that focuses only on this? Sameer. -- Research Scholar, Department of CSE, IIT Bombay http://www.it.iitb.ac.in/~sameerds/ _______________________________________________ Dia-list mailing list [email protected] http://mail.gnome.org/mailman/listinfo/dia-list FAQ at http://live.gnome.org/Dia/Faq Main page at http://live.gnome.org/Dia
