another beginning of idea for the interface implementation:

I agree on the idea to allow a list of several colors, but it has to be fast'n'easy to use (not to manually mark each frame, but select the color to use when creating it.. that of course should also be possible to change after, but not only)

I think marking frames with arbitrary colours is a good way to go about it, as we should probably stay unopinionated on what exactly it is the user wants to label. There's already a point of contention since the typical traditional animation process also adds a breakdown/extremes in addition to the keyframes and inbetweens.

Wouldn't it make sense to change this to arbitrary color coding for frames? Because Krita doesn't differentiate between keys and betweens yet especially because we don't have transformation tweening yet(animated transform masks and filters)

I investigated this a bit. It effects the animation and the timeline docker.

I suspect this may be fixes with this one: https://quickgit.kde.org/?p=calligra.git&a=commit&h=124e2aaae18756df77c57fd2811f723f55552b60

So, this only happens on 3.0, and seems to be happening with any file that contains animations.

2. the solution you provided might be actually better !

Fixed

Fixed in http://commits.kde.org/calligra/cb68b5ed61e674d5ee2d0eca8da8397ea896e842

1. set the default configuration to a gaussian distribution instead of a constant 49/100.

Fixed in http://commits.kde.org/calligra/277d8c9048c8d15869ef4e3ed3fe0ff91ee871e7

Fixed in https://quickgit.kde.org/?p=calligra.git&a=commit&h=462f63eb5ce6a2b63e2e7629ef36f4e4a9108f69

New proposal

For play, when need basically two things:

• a simple play that start at current frame to the end (and loops),
• a "quick play" that plays only a small defined amount of frames before/after current position, this could be 1s around current position by default (so 0.5s before and after), with a setting somewhere to change it for those who want more or less..

(-> play selection is not so useful)

Fixed in http://commits.kde.org/calligra/a060ae1514036e8057248304e9772a1af089b7a6

Here is a draft Timeline GUI implementation

Hint: add a button to hide extra layer properties icons in the timeline

Just attach a spine screenshot

new mockup attached. I added the litghtbox type of behavior for the onion skin properties. It sounds like that needs to be a docker (it is a big wide though).

this looks good

Yes, something like this.
It has to be accessible in a docker and fast to use to can adjust those very often on the fly.

tim: you are mentioning a lot of UI controls. I imagine you are referring to adding functionality like TVPaint is doing...http://i.ytimg.com/vi/YOzRgy15D6s/maxresdefault.jpg

ps: and with it a way to edit opacity on several sliders at the same time, like dragging across all sliders to set their values.

Timeline proposal looks good, but onionskin miss important thing:
We need to have several keyframes available before and after (like 10 on each side) each with its own opacity slider.
So we need a kind of row of sliders for that.