Add common preR13 POLYLINE and VERTEX entities

[michal-josef-spacek]

In https://github.com/LibreDWG/libredwg/issues/713 we discussed that PR is ugly and we need common POLYLINE and VERTEX entities.

[michal-josef-spacek]

I created https://github.com/LibreDWG/libredwg/pull/724 with:

• Comment updates
• New preR13 POLYLINE and VERTEX structures and API
• preR13 decoding and encoding of DWG.

[michal-josef-spacek]

@rurban What should be next? Do we need conversion to special entities like POLYLINE_2D in decoding/encoding? Or in different place?

[rurban]

Hmm, still ugly. I'm experimenting with both

[michal-josef-spacek]

I will update PR with renamed variables. Thank you.

[michal-josef-spacek]

@rurban Do we need some update in dwg_api.c for this new POLYLINE_R11 entity?

[rurban]

Sure, see my fixups

[rurban]

Or just use common POLYLINE_R11 and VERTEX_R11 macros in the dwg.spec. This way no need for extra structs and seperation.

[michal-josef-spacek]

I am working on it. I will prepare a new PR for it. I was fixing DXF yesterday.

[rurban]

I'll add the other branch soon, with a COMMON_POLYLINE_R11 and VERTEX macro in the spec.

[rurban]

So now we have now alternative implementations.

• The elegant one with an extra POLYLINE_R11 entity, which has the missing problem of up- downconverting across r11.
• The simple one, with common entity fields, including all the r11 fields, which are not relevant to the special entity in question. We could skip them with compile-time branches (macros).

I"m tending to the 1st branch, with the converters.

[michal-josef-spacek]

Thank you for the implementation of the second one.

I wrote this first one because I thought that you don't want to have all variables in structure. I tend to implementation with the simplest structures personally, but conversions are not easy too. Conversions are only in s few use cases too.

[rurban]

It's not so important, more convenience.

I"m still fixing other bugs with r11 plines and vertices, but it"s ready soon. #754