Timeline/Frame ranges inconsistencies in UI
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Description

T39484 raised that timeline frame range representation actually show (real_length - 1) interval… So e.g. a scene having same start and end frame is shown as zero length. This is also inconsistent with how caches are drawn in same window (they start at -0.5 frame and end at +0.5 frame), which allows to represent the real length, assuming 'frame' itself as a sort of “center” value.

To fix T39484 I simply made same thing for frame range, but this was to quick in fact, we need a design decision here and make it consistent in all time-related windows (timeline, VSE, MCE, animations, etc.).

@Sebastian Koenig (sebastian_k) proposed to rather draw a [start, end+1] interval, adding a small green square of one frame width to the cursor:

Details

Type
Design

Every solution here has a downside, either the duration is 'wrong', or the start/end frames are in 'wrong' place. It depends which one you care about more.

Personally I have no preference here. Maybe the animation team should be consulted here @Joshua Leung (aligorith), @Nathan Vegdahl (cessen), @bassam kurdali (bassamk).

I'm fine with sebastian's proposal though the 'wrongness' doesn't really bother me; some notes:
-probably best to stay consistent in all the time editors
-some things like keyframes don't have a 'duration' as such - I guess it is fine if they show up at the beginning of the one frame interval

Ok, will try to get a patch working this way (and yes, keyframes should not be 'extended', only the currframe cursor would get that small 'one frame' green block ;) ).

Personally, I haven't actually ever been bothered by the current display. Agreed with @bassam kurdali (bassamk)'s point regarding keyframes not having a "duration" - this is one of the things that is different between the way we display things vs say the dopesheet in Maya.

If it does matter that the end frame doesn't stop abruptly on the end-frame value, perhaps the range could be something like [start, end + 0.9] or so. Apart from that no other changes are needed.

Didn't want to meddle with design decisions, but as I raised T39484...: To me, a rectangle enclosing the current frame would be most intuitive:


All frames are light-gray (including end frame), and labels are in the center of the frame.

Oh, and regarding key frames in the dope sheet window: It must be a dot (visualized as a diamond ) because it marks the point in time when a property has a certain value. This can also be somewhere in the middle of a frame (ctrl+MouseMove while grabbing), and there could be multiple key frames within a scene's frame. Just my 2c.

Once again, yes, it’s obvious keyframes are not concerned here, since they are a precise time position, and have no duration per se.

I think we all agree to the same solution (to summarize: extend last frame to get real range, add '1frame' visualization block to currtime cursor, like it’s already done in some places), so will propose a patch about this, it will be easier to talk from it (when I have time, this ain’t exactly top priority topic either ;) ).

Sorry, I just see this task's type is "design", not "bug". Accidently went the wrong way. Won't happen again. :)