Geometry Boost List: Re: [geometry] translation and rotation proposal

Subject: Re: [geometry] translation and rotation proposal
From: Barend Gehrels (barend_at_[hidden])
Date: 2013-06-23 13:46:38

Hi Bruno,

On 22-6-2013 15:37, Bruno Lalande wrote:
> Hi,
>
>
>     Ok, the Vector Concept looks obvious as it would be probably
>     exactly the same as Point.
>
>
> Yep, as I said one question is: should vector_type<point> just return 
> point by default, and users interested in vector/point differentiation 
> would have to state it by specializing the metafunction (or calling a 
> convenience macro)? or should it enforce point/vector differentiation 
> straight away? Personally, for backward compatibility and "simplicity 
> by default" reasons, I'd vote for the former.
>
>     Probably only one questionable thing is coordinate_system. Should
>     we allow Vectors with coordinates defined in some other than
>     cartesian coordinate system?
>
>
> No idea, not familiar enough with non-cartesian systems to say if it 
> makes sense. Barend what would you say?

Yes, it makes sense and would need a similar (or same) interface... 
return_difference<Point>(point1, point2) would be applied to Cartesian 
points or to Spherical / Geographic points. For lat-lon it would return 
a course/distance pair, this way you can add the calculated vector to a 
point1 and get point2 back. In this case a vector-type is something 
different than a point-type, more than in cartesian cases.

Regards, Barend