kopia lustrzana https://gitlab.com/gerbolyze/gerbonara
54 wiersze
2.8 KiB
ReStructuredText
54 wiersze
2.8 KiB
ReStructuredText
Apertures in Gerbonara
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======================
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Gerbonara maps all standard Gerber apertures to subclasses of the :py:class:`.Aperture` class. These subclasses:
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:py:class:`.CircleAperture`, :py:class:`.RectangleAperture`, :py:class:`.ObroundAperture` and
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:py:class:`.PolygonAperture`. :doc:`Aperture macro<aperture-macros>` instantiations get mapped to
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:py:class:`.ApertureMacroInstance` (also an :py:class:`Aperture` subclass). The basic aperture shapes each support a
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central hole through their :py:class:`~.CircleAperture.hole_dia` attribute. This "hole" is just a cut-out in the
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aperture itself, and does not imply an actual drilled hole in the board. Drilled holes in the board are specified
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completely separately through an :py:class:`.ExcellonFile`.
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Gerbonara is able to rotate any aperture. The Gerber standard does not support rotation for standard apertures in any
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widespread way, so Gerbolyze handles rotation by converting rotated standard apertures into aperture macros during
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export as necessary.
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Aperture generalization
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-----------------------
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Gerbonara supports rotating both individual graphic objects and whole files. Alas, this was not a use case that was
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intended when the Gerber format was developed. We can rotate lines, arcs, and regions alright by simply rotating all of
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their points. Flashes are where things get tricky: Individual flashes cannot be rotated at all in any widely supported
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way. There are some newer additions to the standard, but I would be surprised if any of the cheap board houses
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understand those. The only way to rotate a flash is to rotate the aperture, not the flash. For cirlces, this is a no-op.
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For polygons, we simply change the angle parameter. However, for rectangles and obrounds this gets tricky: Neither one
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supports a rotation parameter. The only way to rotate these is to convert them to an aperture macro, then rotate that.
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This behavior of using aperture macros for general rotated rectangles is common behavior among CAD tools. Gerbonara adds
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a non-standard :py:attr:`.RectangleAperture.rotation` attribute to all apertures except :py:class:`.CircleAperture` and
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transparently converts rotated instances to the appropriate :py:class:`.ApertureMacroInstance` objects while it writes
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out the file. Be aware that this may mean that an object that in memory has a :py:class:`.RectangleAperture` might end
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up with an aperture macro instance in the output Gerber file.
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Aperture classes
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----------------
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.. autoclass:: gerbonara.apertures.Aperture
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:members:
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.. autoclass:: gerbonara.apertures.CircleAperture
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:members:
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.. autoclass:: gerbonara.apertures.RectangleAperture
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:members:
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.. autoclass:: gerbonara.apertures.ObroundAperture
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:members:
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.. autoclass:: gerbonara.apertures.PolygonAperture
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:members:
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.. autoclass:: gerbonara.apertures.ApertureMacroInstance
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:members:
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