Finding which F-Curve (if any) drives the blend factor or volume of a strip is
fairly expensive (it has to search all the curves to find the one matching the
name). Speed that up by:
- Doing the f-curve lookups in parallel for all the visible strips,
- The found curve is stored in StripDrawContext, so this also avoids finding
the "volume" curve twice for the same strip (once for waveform, once for
fcurve overlay).
Viewing Sprite Fright Edit v135 whole timeline on Ryzen 5950X (Win10/VS2022):
timeline repaint 18.5ms -> 7.7ms
Pull Request: https://projects.blender.org/blender/blender/pulls/128015
a8767d943d