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List:       sqlite-users
Subject:    Re: [sqlite] R*Tree / In Memory Database / GUI Object Hit Testing
From:       Clemens Ladisch <clemens () ladisch ! de>
Date:       2018-05-20 13:56:02
Message-ID: 3985d5fd-8161-493e-764b-f197d5d1439b () ladisch ! de
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Robert M. Münch wrote:
> I'm wondering if the R*Tree index of Sqlite could be used to implement
> GUI object hit testing?

Yes, that would be possible.

> We could populate a r*tree table with (runtime-object-memory-pointer,
> x0, y0, x1, y0) pretty easy. Now the user clicks the mouse somewhere,
> and we would like to get back all rectangles that were hit. Since we
> don't have any overlapping we could even sort the rectangles by size
> and get the whole tree-path to the leaf rectangle back.

In general, your object tree already is the equivalent of an R-tree,
i.e., just doing hit-testing in the objects themselves should be just
as efficient.

An (R-tree) index is more useful when you have a bunch of independent
object that are not already organized in a tree.


Regards,
Clemens
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