On Mon, 2009-02-09 at 13:13 +0200, Dov Grobgeld wrote: > The problem with any general canvas solution is that it can only make > limited assumptions about the scale and subdivision of the data. E.g. > if you > know that all your line segments are of certain max size, then you can > use > that knowledge to do a more efficient lookup. Look e.g. at Google > Earth that > is presenting different info depending on the zoom-in. I assume that > it is > achieving that through a heavy preprocessing of the data that is > cached on > the server. This is difficult to do with a general purpose canvas > object. > That's why I turned to a callback model in my widget > gtk_image_viewer , that > is much more flexble, though you have to do more work on your own. This canvas comparison already mentions the idea of "non-scaled items" which is maybe a sub-set of what you mean, though no canvases seem to implement it yet: http://live.gnome.org/ProjectRidley/CanvasOverview It seems like something that could be done, though many canvas authors don't seem to like the idea of having any (even optional) higher-level concepts in their canvases, even where a lower-level implementation would make the higher-level concepts easier to implement. -- murrayc@xxxxxxxxxxx www.murrayc.com www.openismus.com _______________________________________________ gtk-list mailing list gtk-list@xxxxxxxxx http://mail.gnome.org/mailman/listinfo/gtk-list
