Re: [Lib2geom-devel] Path translations

[Johan E. <jbc...@sw...>]

On 13-11-2013 16:50, Krzysztof Kosiński wrote:
> 2013/11/12 Johan Engelen <jbc...@sw...>:
>> As far as I can see now, all (current) Curve types *are* closed under
>> translations. I think we should enforce this for Curve. I.e., each Curve
>> must implement
>>          virtual Curve &operator+=(Point const &);
> I think the method should be:
> virtual Curve &operator*=(Translate const &t) {
>      *this *= Affine(t);
>      return *this;
> }
>
> Rationale:
> 1. It's not immediately obvious what adding a point to a curve means.
> For instance, for BezierCurve it might plausibly mean adding a control
> point.

Ok, that makes sense.

> 2. For curves that don't implement the specialization, we just
> multiply by a generic affine.

This is not possible. Because curves are not closed under Affine 
transform, there is no operator*=(Affine). If you want to transform a 
Curve, you have to call
     Curve* Curve::transformed(Affine const&)

I'll clean up the work and commit my changes, so you can see.

Cheers,
   Johan