Geometry Boost List: Re: [geometry] nsphere and views names

Subject: Re: [geometry] nsphere and views names
From: Barend Gehrels (barend_at_[hidden])
Date: 2013-06-20 17:59:26

Hi Adam,

On 20-6-2013 19:36, Adam Wulkiewicz wrote:
> Adam Wulkiewicz wrote:
> ...
>>
>> I've called it center_view because it may be used to 'see' some Geometry
>> as it's center. It might be used also for ellipses, boxes, etc.
>>
> ...
>>
>> E.g. in OpenStreetMap there are WAYs which are vectors of points and
>> describe LineStrings or Rings (it the first point is repeated at the
>> end). We could e.g. have linestring_view which allows to see a vector as
>> a Linestring and ring_view which allows to see vector as a Ring. And
>> those names could also be used for other points-containers/Geometries
>> (those classes could be Derived from some specialized implementations)
>>
> ...
>>
>> What do you think about those 'new' views? If you like it, should they
>> reside in some new namespace?
>>
>
> Maybe something like this:
>
> geometry::view::as_centroid / as_center_point / as_center_point
> geometry::view::as_ring
> geometry::view::as_linestring
>
> ?

Yes, this has been brought up earlier. It is certalinly useful to view a 
geometry as another geometry type,  and view::as_ring seems intuitive to me.

view::as_centroid is maybe too specific, maybe just view::as_point ?

Bruno did also have ideas about this.

We already have the "view_as" structure and make_view_as function, which 
basically can do things like this. This is designed as:

boost::geometry::make_view_as<point>(sphere), which obviously returns a 
point. This is not really worked out yet. See views/view_as

The box_view is indeed the other way round, it sees a box as something 
else...

So good this topic has been brought up again, thanks.

See also my other mail about closeable_view, and reversible_view, but 
that is more viewing a Boost.Range like thing as another Boost.Range 
like thing, so not exactly the same.

Regards, Barend