Saturday, May 31, 2008


I thought I'd post some snapshots of the new timeline code. I wanted to test the dragging code independently of PiTiVi, so it is being run from an external script.

Timeline displaying some test items at their default size.

The Timeline can be enlarged, in which case the items inside are automatically enlarged. This takes advantage of goocanvas's scaling.

The timeline is now fully reorderable, though the interaction is far from perfect. It's not as smooth as it was in my early prototype, but my early prototype didn't handle items of varying widths. I'm anxious to move on, but I really want to make sure that this code works properly on its own before I throw in the added complexity of MVC.

One issue which I haven't yet decided how to handle is transitions. Should I allow multiple transitions to be moved next to each other on the timeline? What would that mean? I don't think there's a use case for multiple transitions in between two clips. If I'm not to allow multiple transitions, then I have to think of a way to prevent them from stacking against each other, which could get hairy.

Currently I have a SimpleTimeline which derives from Canvas(). This in turn uses a more general HList(), which I had hoped to make as general as possible. However, I think my goal of having a generic, re-orderable list class is not going to work. There is too much application-specific behavior in the timeline. Tomorrow, I'm going copy the list code directly into the SimpleTimeline class, which already implements the re-orderable portion of the list anyways.

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