CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

On 01/22/2013 12:03 PM, Shriramana Sharma wrote:
> Hello. 
> CGAL-4.1/doc_html/cgal_manual/Boolean_set_operations_2/Chapter_main.html#Subsection_19.4.3
> the documentation only shows how to initialize a Bezier curve from a
> file stream using operator>>. However the operator>>  for Curve_2 is
> defined in CGAL-4.1/include/CGAL/Arr_geometry_traits/Bezier_curve_2.h
> and it calls the constructor starting near l 353 which reads:
>
>    _Bezier_curve_2 (InputIterator pts_begin, InputIterator pts_end) :
>
> In my program I'd like to initialize a bezier curve directly from a
> vector of control pts, and not from a file. My questions:
>
> 1) Is the above constructor part of the official API so that I can
> safely construct my high-level Curve_2 class (which gets redirected
> via typedefs to the above _Bezier_curve_2 class) using the pair of
> begin/end iterators?
It is documented here:
http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Arrangement_on_surface_2_ref/Class_Arr_Bezier_curve_traits_2.html

> 2) IIUC the begin/end iterator is often used in CGAL.
>
> 2a) Is this to enable the user to select any subset of the list used for 
> input?
>
> 2b) Would it be possible to provide a useful overload which takes a
> (const?) ref to a vector object and doesn't require the user to
> manually specify the begin/end iterators?
This is the classical way to deal with sequences in the STL.
In the future, we will be using the Range concept which will allow
you to pass directly a container model of this Range concept.

> 3) (OK so this one is probably silly but well I'm relatively
> inexperienced so just to be sure:) I am working with contours that can
> have straight line or quadratic or cubic bezier segments. I suppose I
> just input the relevant number of ctrl pts per bezier i.e. 2,3,4 and
> the library will take care of the boolop calculations correctly?
It should yes.

Sebastien.

> Thanks!