On Tue, 13 Jan 2009, Raphaël Jacquot wrote:
What I don't understand - with your change and before - is that paint speed seems to depend on the amount of data in the layer even if it's outside the view.That's to be expected. Even with a spatial index (AFAIK josm still doesn't use one yet), looking up the objects inside a give bounding box ("the view") is dependant on the total number of objects. For example, a 2D-PR-Tree lookup is about O(sqrt(n)) [1], with n being the total number of objects stored in the tree.imho, we should use one, as O(sqrt(n)) is still much better than the linear O(n) that josm currently requires to go through the entire set of things that are available to be drawn
That is not so easy, because JOSM has no encapsulated data structures.But when we get the O() reduced a lot, then it will get a lot faster as well. When optimizing not only the argument to O(), but the function itself is also important (This is what Ulf has successfully done and which has still some potential).
Ciao -- http://www.dstoecker.eu/ (PGP key available)
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