This adds three corner types: `Round` `Sharp` and `Flat`.
These control how the corner of `Grease Pencil` line strokes are rendered.
- The `Round` type draws circular arcs, and is what `Grease Pencil`
currently supports and is default.
- The `Flat` type cuts off the tip of the corner.
- The `Sharp` type allows for sharp corners to be created.
If the angle is sharper than `Miter Limit` then the tip will be cut like `Flat`
These three types match the main types of `line joins` present in `SVG`
files.
This data is stored in one `Point` attribute called `miter_angle`.
This stores both the `Corner Type`, the `Miter Limit` and defaults to
the `Round` type.
This PR adds:
- Rendering of the corner types.
- An operator for setting the `Corner Type` and `Miter Angle` attribute.
- Corner types to the `Outline` operator and modifier.
Part of #145380.
Pull Request: https://projects.blender.org/blender/blender/pulls/143688