Fixed #704 (DXF reader: rational splines not supported)

[klayoutmatthias]

No description provided.

[lukasc-ubc]

Interesting! Are Splines accessible as a primitive object in python? Lukas Chrostowski Professor, Electrical and Computer Engineering University of British Columbia Quantum Matter Institute Member, College of the Royal Society of Canada http://www.mina.ubc.ca/lukasc http://siepic.ubc.ca https://qmi.ubc.ca/about/directory/lukas-chrostowski

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On Jan 20, 2021, at 2:17 PM, Matthias Köfferlein ***@***.***> wrote:  You can view, comment on, or merge this pull request online at: #705 Commit Summary Fixed issue #704. TODO: replace algorithm by De Boor, check if accuracy is still maintained. Switch spline interpolation algorithm to De Boor for better numerical stability. Updated tests with DXF accuracy test, provide a warning for unsupported SPLINE types. File Changes M src/plugins/streamers/dxf/db_plugin/dbDXFReader.cc (208) M src/plugins/streamers/dxf/db_plugin/dbDXFReader.h (2) M src/plugins/streamers/dxf/unit_tests/dbDXFReaderTests.cc (28) Patch Links: https://github.com/KLayout/klayout/pull/705.patch https://github.com/KLayout/klayout/pull/705.diff — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub, or unsubscribe.

[klayoutmatthias]

@lukasc-ubc Excellent idea! And done (awaits merge): #706 :)

[victorliu]

This does not appear to be fixed. Using KLayout version 0.27.11, and opening the DXF generated with the following script:

import math
import ezdxf

dwg = ezdxf.new(dxfversion='AC1015')
ms = dwg.modelspace()

ms.add_circle((0,0), 0.9)
ms.add_circle((0,0), 1.1)

r2 = math.sqrt(0.5)
spline = ms.add_rational_spline([(1, 0), (1, 1), (0, 1)], [1, r2, 1], 2)
spline.dxf.flags = 12

dwg.saveas('klayout_rational_spline_test.dxf')

This should produce a quarter circle between the two full circles. Instead, what I see is a non-rational Bezier with all weights 1:

[klayoutmatthias]

Please create a new issue. This one isn't an issue, but a pull request and it is closed.

BTW: rational splines are supported. The problem is the order of records that ezdxf produces. The test file I got for developing that feature has a record sequence of

10 20 30 41  (x y z w) first point
10 20 30 41  (x y z w) second point
...

while ezdxf produces:

41 41 41 ... (w vector)
10 20 30  (x y z) first point
10 20 30  (x y z) second point
...

KLayout does not digest this order properly. When I manually change it, the circle looks at it is supposed to.

Matthias

[klayoutmatthias]

Never mind. I created an issue for this: #1173