[geos-devel] Problems with BufferOp when using BufferParameters

[Markus Meyer]

Hi everyone,

I'm using GEOS 3.3.0 on Microsoft Visual Studio 2008 (Windows 7) for 
buffering lines using BufferOp.

I would like to use the BufferParameters class to control extended 
parameters. However, it seems that I must be using the BufferOp class 
the wrong way because my parameters are never accepted. To explain this, 
I created a simple test program which offsets a rectangle.

When I do the buffering with the static function Buffer::bufferOp() the 
resulting geometry looks OK:

     // Working code
     geos::geom::Polygon* pPolygon = dynamic_cast<geos::geom::Polygon*>(
         geos::operation::buffer::BufferOp::bufferOp(
             pLineString, fOffset, 16,
             geos::operation::buffer::BufferParameters::CAP_ROUND));

When I do the buffering by using the BufferOp and BufferParameters class 
directly, the resulted geometry looks very strange:

     // Not working code
     geos::operation::buffer::BufferParameters params(
         16,
         geos::operation::buffer::BufferParameters::CAP_ROUND);

     geos::operation::buffer::BufferOp op(pLineString, params);
     geos::geom::Polygon* pPolygon =
         dynamic_cast<geos::geom::Polygon*>(op.getResultGeometry(fOffset));

 From my understanding, the results of both code snipets should be the same.

Here you can find a plot of the results in both cases:

http://www.mesw.de/support/geos_rectangle_buffer_fail.png

Any help is greatly appreciated.

Best regards,
Markus

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