Add option to use layer names in DXF export (#2439)

[goanscryca]

This PR addresses #2439 by adding support for exporting DXF layers with their original layout layer names instead of prefixing layer/datatype numbers (e.g. PAD instead of L18D0_PAD).

Changes

1. DXFWriterOptions (dbDXFFormat.h):
   • Added use_layer_names boolean flag (defaults to false for backwards compatibility).
2. DXFWriter::write (dbDXFWriter.cc):
   • Uses db::SaveLayoutOptions::LP_AssignNameWithPriority when use_layer_names is true, preserving layer names directly as DXF layer names.
3. GSI & Python/Ruby bindings (gsiDeclDbDXF.cc, dbcore.pyi, laySaveLayoutOptions.rb):
   • Added dxf_use_layer_names / dxf_use_layer_names= accessors on SaveLayoutOptions.
4. GUI Option Page (DXFWriterOptionPage.ui, layDXFWriterPlugin.cc):
   • Added "Use layer names (don't prefix with layer/datatype numbers)" checkbox to the DXF export options dialog.
5. XML persistence (dbDXF.cc):
   • Added XML serialization for use-layer-names.
6. CLI buddy options (bdWriterOptions.h, bdWriterOptions.cc, bdBasicTests.cc):
   • Added --use-layer-names flag to generic writer options.
7. Unit tests (dbDXFWriterTests.cc, bdBasicTests.cc, laySaveLayoutOptions.rb):
   • Added TEST(LayerNames) verifying DXF export with and without use_layer_names.

Fixes #2439.

[Kazzz-S]

@goanscryca,

Thank you for implementing PR #2447!
I built and tested the PR on macOS, and my testing shows it provides a direct solution to the original request in #2439.

First, I confirmed the new DXF writer option:

A. Layers without names

When the original KLayout layers do not have layer names:

the exported DXF keeps the conventional L<layer>D<datatype> names:
For example:

• 1001/0 → L1001D0
• 2001/1 → L2001D1
• 3001/1 → L3001D1

---

B. Layers with names

When the KLayout layers have names:

with "Use layer names (don't prefix with layer/datatype numbers)" enabled, those names are directly used as the DXF layer names:
For example:

• AAA 1001/0 → AAA
• BBB 2001/1 → BBB
• CCC 3001/1 → CCC

---

This is exactly the behavior @laurentc2 was looking for in the original issue: existing KLayout layer names are now preserved directly in the DXF export, while unnamed layers retain their conventional layer/datatype-based names.

Thank you very much for implementing this feature!

Best regards,
Kazzz-S

[klayoutmatthias]

Hi @goanscryca,

thanks for the PR. I think it's solving the issue of Laurent. I had a different solution in mind - if you do GDS to DXF translation, you will always need a layer mapping and my proposal was to have a flag that strips layer/datatype upon mapping. So a change in input translation rather than output translation. I think that this change has more use cases, i.e. for other name-based formats such as CIF.

In general, I appreciate if people talk to me before implementing something.

Anyway, I think your patch is valid and useful, conforming with the code style and it comes with tests, which is good.

I have some remarks though:

• the *.pyi files are auto-generated, so your changes to dbcore.pyi will be overwritten
• you do not need to use "dxf_use_layer_names?|#dxf_use_layer_names" for the method declaration of the property getter. "dxf_use_layer_names?" is enough.
• you made an implicit release decision by saying the new properties are added in 0.30.13 - basically there should be a milestone plan first and then the implementation.
• while fixing a small bug of mine in dbDXF.cc (the XML entity for the DXF writer options is called "cif") you created a backward compatibility problem - people having configuration files that set "polygon_mode" on DXF will now have their setting ignored. In such a case I personally tend to put in a comment in the code like "'cif' is wrong, but it's kept for backward compatibility" and keep the wrong code, but we can also change it as see what's happening. I can always blame it on this PR :)

Matthias