To start, I want to thank everyone who has helped me so far on previous problems I have had with working through the CGAL Library, it is greatly appreciated.
Background on myself: I am still very new with C++ and my coding experience is in MATLAB so there is a lot of concepts that I am learning very quickly and are therefore very new to me, so please excuse my erroneous language that I may use with regard to C++.
The Problem:
I have recently wrote some code that finds the Minkowski sum of a polyline and a circle (i.e., buffer of a polyline) using the code found in the documentation of Boolean Set Operations on General Polygons.
Here, a General_polygon_set_2 concept is utilized in the output, and if the output code is used from the example above I can get the following output of a Polygon_with_holes_2 class:
48 [775.718 -206.547 --> 769.134 -157.991] (769 -157 1 1) [769.134 -157.991 --> 770 -157] (769 -157 1 1) [770 -157 --> 768.866 -156.009] [768.866 -156.009 --> 762.282 -107.453] [762.282 -107.453 --> 703.282 -115.453] [703.282 -115.453 --> 708.072 -150.778] ...
7 15 [549.239 -193.612 --> 569.403 -216.422] ... 3 [456.756 -657.812 --> 657.930 908.153] ...
Here, if I understand correctly, the first integer refers to the number of a vertices in the .outer_boundary() , followed by descriptions of the curves for each "edge" of the general polygon. In my problem, the outputs will only consist of linear functions and circular arcs.
Linear: [775.718 -206.547 --> 769.134 -157.991]
Circular Arc (x-monotone): (769 -157 1 1) [769.134 -157.991 --> 770 -157]
The linear element is simple, go from this x-y coordinate to this other one by a line. As for the the circular arc, it is little bit more different, it says to use this circle described by the arguments in these brackets () to go from this x-y coordinate to this other one contained in these brackets []. The arguments to circle are: (x,y,radius,orientation).
Next, since we have holes, after the .outer_boundary() has been written out, two more integers are displayed. The first one states the number of holes, the second states the number vertices in this hole, then followed by those vertices for that hole. Then once that hole is written out, another integer is written describing the number of vertices in that hole, and this then continues for all of the holes, completing the description of the polygon.
So with that, my current problem is parsing out each individual curve one at a time so that I can do operations on them.
I have the following functions from the documentation to work with:
.outer_boundary(): returns the general polygon that represents the outer boundary.
.holes_begin(): returns the begin iterator of the holes.
.holes_end():
So my thought is to break the General_polygon_set_2 to General_polygon_2, then break that down into the .outer_boundary() and the different holes. Finally, for each set of curves, break those down into individual curves.
I am not really sure how to go about this, I just know that I need individual curve data so I can do my own operations on them. Any help, will be, as always, greatly appreciated!
Note: I actually deleted this post after reading through the arrangements documentation thinking that this was too obvious of an answer, but after sometime I still really do not see how to pull this info properly, I think the biggest issue is in my lacking knowledge of C++. Sorry about this being a noob-ish question.
Solution in Progress:
list<Polygon_with_holes_2> res;
S.polygons_with_holes (back_inserter (res));
list<Polygon_with_holes_2>::iterator i = res.begin();
Polygon_with_holes_2 mink = *i;
minkOuter = mink.outer_boundary();
cout << minkOuter << endl;
int numHoles = mink.holes_end()-mink.holes_begin();
cout << numHoles << endl;
Now I am working on isolating the holes, followed by breaking those down into each individual curve.