Continuing #140360
This PR moves keyframe theme properties from editors into Common.
Besides Dope Sheet, keyframe properties were in:
- Sequencer (almost all types, and might use more in the future)
- 3D Viewport, where the active object name overlay used a separate Object Keyframe color when
it had keyframes on the current frame. Now it uses the common Keyframe Selected color, instead
of having its own property just for this little text.
- Keyframes in Movie Clip Editor were hard-coded white, now they use a common Keyframe color.
Selected colors used wrong long key selected color, now they use common Keyframe Selected color.
- Movie Clip Editor also used separate colors for what it called "Strips", but they are visually
the exact same thing as "long keys" in Dope Sheet, so they use common long key colors now.
There are Keyframe Border properties in Dope Sheet, Sequencer, and NLA, but they're not shared
because they're drawn on very different backgrounds, in different sizes, with different fill colors, so
it's difficult to make one color work for all of them, and it can restrict customization and accessibility.
Video in PR
---
Details:
- Long keys in Dope Sheet/Clip Editor and Strips in NLA used the same internal "strip" attribute.
Those needed to be separated to properly use long key colors in common, without worrying
about affecting unrelated things, and those two are as unrelated as they can get.
To properly separate them I added new "long_key" attributes, and corresponding
`TH_LONGKEY` and `TH_LONGKEY_SELECT`.
- Long keys in Movie Clip Editor had hardcoded alpha. Now they use alpha of the theme color.
Pull Request: https://projects.blender.org/blender/blender/pulls/144259
cb22938fe9