id,summary,reporter,owner,description,type,status,milestone,component,version,severity,resolution,keywords,cc
13636,distance calculation can be wrong for rings with collinear segments,stfn <p1433025@…>,Barend Gehrels,"While unit-testing our code using boost::geometry, I stumbled upon a weird distance calculation: For two rings that are perfect 2d boxes and share the orientation and one segment length, their distance is calculated as zero although they are clearly not intersecting:

https://wandbox.org/permlink/Z9DMLo52IdhZRCFb

I made a rough sketch of the situation: https://www.desmos.com/calculator/7jbmeu9jqq.


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Note the line 


{{{
// slightly change the values
vehicleRing[2] = Point2D(vehicleRing[2].x() + 1e-10, vehicleRing[2].y() + 1e-10);
}}}


.. changing vehicleRing[0] or vehicleRing[1] also results in zero distance, whereas slightly moving vehicleRing[2] results in the expected distance. 

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Sorry for being lazy and not finding a simpler test-case (resp. simpler numbers), I just copied the values I generated in my own testing pipeline.",Bugs,new,To Be Determined,geometry,Boost 1.67.0,Problem,,distance ring collinear pythagoras segment,