in reply to Re: polygon buffering algorithms
in thread polygon buffering algorithms

................................... ................................... ................................... ................................... .....!!!!!!!!!!!!!!!!!!!!!!!!!..... .....!!!!!!!!!!!!!!!!!!!!!!!!!..... .....!!!!!!!!!!!!!!!!!!!!!!!!!..... .....!!!!!!!!!!!!!!!!!!!!!!!!!..... ...............!!!!!!!!!!!!!!!..... ...............!!!!!!!!!!!!!!!..... .....!!!!!!!!!!!!!!!!!!!!!!!!!..... .....!!!!!!!!!!!!!!!!!!!!!!!!!..... .....!!!!!!!!!!!!!!!!!!!!!!!!!..... .....!!!!!!!!!!!!!!!!!!!!!!!!!..... ................................... ................................... ................................... ...................................

The above with $d == 3 gives a weird polygon, but that's ok as long you're expecting it.

................................... ..7..............................8. ................................... ................................... .....!!!!!!!!!!!!!!!!!!!!!!!!!..... .....!!!!!!!!!!!!!!!!!!!!!!!!!..... .....!!!!!!!!!!!!!!!!!!!!!!!!!..... ..3..!!!!!!!4!!!!!!!!!!!!!!!!!..... ...............!!!!!!!!!!!!!!!..... ...............!!!!!!!!!!!!!!!..... ..6..!!!!!!!5!!!!!!!!!!!!!!!!!..... .....!!!!!!!!!!!!!!!!!!!!!!!!!..... .....!!!!!!!!!!!!!!!!!!!!!!!!!..... .....!!!!!!!!!!!!!!!!!!!!!!!!!..... ................................... ................................... ..2.............................1.. ...................................

Replies are listed 'Best First'.
Re^3: polygon buffering algorithms
by thor (Priest) on Feb 08, 2005 at 19:13 UTC
    You're right...the algorithm that I outlined works for convex polygons. In order to deal with polygons with concavities, I believe that you need to allow for overlap and take the union of all points that lie in the interior. In the case of the polygon that you gave, it would then be a square. Just for my own edification, what is the $d that you're referring to?

    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

      The OP refered to "buffer distance 'd'". That's what I meant by $d. (I added the $ without thinking.)