If you have a set of lines that represents a closed polygon, the following pseudo-code should work 
foreach edge (edges in polygon, clockwise)
   construct parallel line distance d from edge, store it in an array
done
foreach parallel line
   find intersection with next line in array, allowing for wrap around
   store intersection in an array
done
#intersections are the vertexes of your new polygon

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thor

Feel the white light, the light within
Be your own disciple, fan the sparks of will
For all of us waiting, your kingdom will come

In reply to Re: polygon buffering algorithms by thor
in thread polygon buffering algorithms by punkish

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