DXF multilayer support

[sethfischer]

A proposed approach to #1171.

Also supports:

• units (see dxf export: support setting units #1188, Export step/stl in milimeter, export dxf is meter #1259)
• setting color by layer
• setting line type by layer

Closes #1171
Closes #1188
Closes #1259

Todo

• documentation
• tests

Notes

• The ezdxf document object is available via the public API so most features of ezdxf are accessible.
• cadquery.occ_impl.exporters.dxf.exportDXF has be refactored but there is no change to the public API.
• Methods _dxf_* have been refactored to better facilitate unit testing. There is no change to algorithm of these methods.

Example use

"""DXF multilayer demo."""

import cadquery as cq
from cadquery.occ_impl.exporters.dxf import DxfDocument

spline_points = [(90, 50), (83, 60), (65, 50), (50, 33), (33, 40), (15, 35), (0, 35)]
spline = (
    cq.Workplane("XY")
    .lineTo(100, 0)
    .lineTo(100, 35)
    .spline(spline_points, includeCurrent=True)
    .close()
)

circle = cq.Workplane().moveTo(15, 15).circle(10)
ellipse = cq.Workplane().moveTo(45, 15).ellipse(15, 10, 0)
rectangle = cq.Workplane().moveTo(70, 15).rect(10, 20)
fold_line = cq.Workplane().moveTo(80, -5).line(0, 70)

# create the DXF document

dxf = DxfDocument(setup=True)

dxf = (
    dxf.add_layer("layer_cut", color=2)
    .add_layer("layer_line_engrave", color=3)
    .add_layer("layer_area_engrave", color=4)
    .add_layer("layer_fold", color=5, linetype="DASHED")
    .add_shape(spline, "layer_cut")
    .add_shape(ellipse, "layer_cut")
    .add_shape(circle, "layer_line_engrave")
    .add_shape(rectangle, "layer_area_engrave")
    .add_shape(fold_line, "layer_fold")
)

dxf.document.saveas("multilayer-demo.dxf")

Screenshot of resulting multilayer-demo.dxf viewed in LibreCAD:

This still works as expected but is refactored to call DxfDocument and DXF document units are mm:

import cadquery as cq
from cadquery import exporters

result = cq.Workplane().box(10, 10, 10)

exporters.export(result, "export.dxf")

Export DXF with document units other then the default:

exporters.export(
    result,
    "export.dxf",
    opt={"doc_units": 6},  # set DXF document units to meters
)

exporters.exportDXF(
    result,
    "export.dxf",
    doc_units=6,  # set DXF document units to meters
)

[adam-urbanczyk]

You might to want to wait with this until #1226 is merged.

[sethfischer]

You might to want to wait with this until #1226 is merged.

@adam-urbanczyk Will do. Once merged I'll rebase this work on master

[codecov]

Codecov Report

Merging #1267 (758c64b) into master (0aa889c) will increase coverage by 0.07%.
The diff coverage is 97.50%.

❗ Current head 758c64b differs from pull request most recent head ea6acb5. Consider uploading reports for the commit ea6acb5 to get more accurate results

@@            Coverage Diff             @@
##           master    #1267      +/-   ##
==========================================
+ Coverage   94.17%   94.24%   +0.07%     
==========================================
  Files          26       26              
  Lines        5455     5495      +40     
  Branches      926      932       +6     
==========================================
+ Hits         5137     5179      +42     
+ Misses        188      187       -1     
+ Partials      130      129       -1     

Impacted Files	Coverage Δ
cadquery/occ_impl/exporters/dxf.py	97.00% <96.93%> (+4.57%)	⬆️
cadquery/cq.py	92.23% <100.00%> (+0.04%)	⬆️
cadquery/occ_impl/assembly.py	98.60% <100.00%> (ø)
cadquery/occ_impl/exporters/__init__.py	94.11% <100.00%> (ø)

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[sethfischer]

I've rebased this on master pulling in #1226 which introduced parameters approx and tolerance.

Should approx and tolerance be:

1. properties of the DXF document? or,
2. properties of the shape being added?, or
3. properties of both the DXF document and the shape?

1. Properties of the DXF document

Properties of the DXF document applying to all shapes added with add_shape.

dxf = DxfDocument(approx: Optional[Literal["spline", "arc"]] = None, tolerance: float = 1e-3)
dxf.add_shape(shape)

2. Properties of the shape being added

Property of the shape added with add_shape.

dxf = DxfDocument()
dxf.add_shape(shape, approx: Optional[Literal["spline", "arc"]] = None, tolerance: float = 1e-3)

3. Properties of both the DXF document and the shape

Properties of the DXF document applying to all shapes added with add_shape. But specific shapes can have their own approx and tolerance values.

dxf = DxfDocument(approx: Optional[Literal["spline", "arc"]] = None, tolerance: float = 1e-3)
dxf.add_shape(shape, approx: Optional[Literal["spline", "arc"]] = None, tolerance: float = 1e-3)

[adam-urbanczyk]

Definitely a property of the document. You might also add an option to override on per-shape basis, but I personally don't have such a use case.

[adam-urbanczyk]

@lorenzncode you might want to integrate #1278 into this PR

[sethfischer]

@adam-urbanczyk back to you for review.

[adam-urbanczyk]

LGTM, last two remarks regarding diff coverage. Could you extend the tests?

[lorenzncode]

I've added the fix from #1278. Thanks @sethfischer!

[adam-urbanczyk]

Thanks @sethfischer

[sethfischer]

Thank you @adam-urbanczyk and @lorenzncode