Re: [Lib2geom-devel] Path translations

[Krzysztof K. <twe...@gm...>]

2013/11/13 Johan Engelen <jbc...@sw...>:
> Wow, I didn't realize that it's only the HL and VL curve types.
> Not being able to transform Curves without creating a new copy is a very
> high price to pay for HL and VL...

I agree.

On the whole, path handling in 2Geom may require some redesign:

1. There is a hard requirement that the final point of a segment and
the initial point of the next segment in a Geom::Path must coincide
exactly, but each curve stores both the initial point and the final
point. For paths that contain many linear segments we store a lot of
duplicate points. We could think about storing the path data
separately in a more efficient representation and using the
Curve-derived objects only as an interface.

2. The copy-on-write thing currently in Path should probably be moved
to the PathVector level, and Path itself should be based on
boost::ptr_vector or some other pointer container.

3. Path needs to be renamed to Subpath and PathVector needs to become
a real object and be renamed to Path.

> What shall we do?
> I thought Inkscape wants HLineSegment / VLineSegment to be able to fully
> round-trip SVG-d, but when I manually enter H or V in the XML-editor, it is
> immediately converted to normal line segments...

SVG roundtrip does not strictly require having HLine / VLine as
separate classes. For instance, there could be a flag set in the
constructor.

Regards, Krzysztof