* get_referenced_edges(property_value): returns the Edges referenced by the value of a App:PropertyLink, App::PropertyLinkSub or App::PropertyLinkSubList property.
* get_placement_perpendicular_to_wire(wire): returns the placement whose base is the wire's first vertex and it's z axis aligned to the wire's tangent.
* get_extended_wire(wire, offset_start, offset_end): returns a wire trimmed (negative offset) or extended (positive offset) at its first vertex, last vertex or both ends. For example:
get_extended_wire(wire, -100.0, 0.0) -> returns a copy of the wire with its first 100 mm removed
get_extended_wire(wire, 0.0, 100.0) -> returns a copy of the wire extended by 100 mm after it's last vertex
The name of the argument, `projection`, in the old function
is incorrect; it should be `direction`, which was the original
argument's name when this method was split into its own module
(6c00fcf).
After the reorganization of the Draft Workbench,
the `'DraftText'` objects are now of Proxy.Type `'Text'`.
In the `DraftAnnotation` class the `__setstate__` method
was defined to automatically migrate the Type.
The `Arch SectionPlane` only handles `'Text'` objects. If for
some reason there is still an old `'DraftText'` object
which has not been migrated to the new Type, it won't be found.
This is corrected by adding `'DraftText'` to the list of objects
to process.
If the object has a `Shape` it uses its bounding box to enlarge
the page size of the SVG. If it does not have a `Shape`
("Draft Text", "Draft Dimension", other `App::FeaturePython`)
it uses `Draft.get_bbox` to calculate one bounding box
from the viewprovider if possible.
Normally the bounding box is taken from `Shape.BoundBox`.
Certain objects don't have a `Shape`, like `App::FeaturePythons`,
so the bounding box is calculated from `ViewObject.RootNode`.
If it's not a circle nor ellipse nor straight line
convert the curve to BSpline. Move into a subfunction.
Improve a few varible names to be more verbose, like `vertex`
and `edge`.
The angle between the curve and plane is tested for being coplanar,
0 or 180 degrees. The negative test is done earlier so that the
return is done earlier, and the rest of the code is not indented.