Re: [boost] Formal Review: Boost.Polygon starts today August 24, 2009

Subject: Re: [boost] Formal Review: Boost.Polygon starts today August 24, 2009
From: Simonson, Lucanus J (lucanus.j.simonson_at_[hidden])
Date: 2009-08-29 20:41:52

Mathias Gaunard wrote:
> Simonson, Lucanus J wrote:
> 
>> I almost forgot, there is actually a better answer to your question.
>> The operators in the operators namespace are an optional feature of
>> the library.  You can instead use the polygon_set_data objects to
>> perform explicit conversions and use the member operators of the
>> polygon_set_data classes.    
>> 
>>  polygon_set_data<int>(some_polygon) |
>> polygon_set_data<int>(some_rectangle); 
>> 
>> Since operator| is in this case a member function it is found first
>> though ADL. 
> 
> Except this is going to copy some_polygon and some_rectangle to
> initialize the polygon_set_data, right?

Yes, however, polygon_set_data encapsulates the data structure that is the input to my sweep line algorithm.  It needs to be copied to that format anyway so that I can sort and scan it.  The generic operators are implemented by performing the conversion and using the member operator of the polygon_data_data classes.  There is no way to run a sweepline algorithm on a polygon without sorting its edges into the order they are to be scanned, and there's no way to sort a polygon's edges without converting it.

Luke