Re: GSOC Project "Implement boolean operations on polygons" GNU Octave

[John Swensen]

On Mar 15, 2016, at 3:10 AM, PhilipNienhuis <address@hidden> wrote:

Juan Pablo Carbajal-2 wrote

On Mon, Mar 14, 2016 at 4:10 PM, Albu Mihai &lt;

albumihaiupb@

&gt; wrote:

Hello,

My name is Albu Mihai and I am a student at University Politehnica of
Bucharest, more exactly at Computers and Information Technology. I want
to
work at Google Summer of Code 2016 and I chosed you because I like
mathematics and I saw an interesting project you have there, the one with
polygons operations. The proposal I have is to do a dynamic list with the
coords of points that creates the polygons and we use mathematic
functions
to know how are the polygons defined. In this way, we can do easy the
operations.

Hello Albu,

That's great. Read the instructions on the wiki page, and start
coding. If you have questions just ask here on in the IRC channel. Do
not forget to write your application for GSoC on due time.

In order to avoid reinventing the wheel it may be wise to first check what
is already available out there and use proven solutions as much as possible.

A while ago in this mailing list some suggestions were mentioned.

Philip

I would recommend you take a look at a couple of the different existing polygon boolean libraries available. The project ideas page (http://wiki.octave.org/Summer_of_Code_Project_Ideas) has links to four different solutions with compatible licenses (ClipperLib, Boost::Polygon, Boost::Geometry, and KBool) and a link to a partial Octave implementation using ClipperLib. 

I agree with Philip that using an existing solution would make it possible to start tackling the problem of integration with Octave, rather than working on polygon point representations. As far as I know, all of these libraries use the convention of alternating winding direction (clockwise or counter clockwise) to indicate whether the points represent an outer polygon boundary or and inner hole boundary.

John S.