[MPEG-OTSPEC] "anim" feature tag

[Laurence Penney]

Remember that intermediate masters (including when default is intermediate between min and max) disrupt smooth animation, making G2 continuity impossible (even if the app knows the intermediate axis values). That covers a large proportion of variable fonts. Perhaps a font store or a design tool could flag fonts without intermediates or feature variations.

- Laurence

> On 31 Jan 2024, at 15:32, Behdad Esfahbod via mpeg-otspec <mpeg-otspec at lists.aau.at> wrote:
> 
> How would `anim` feature work? Would the client be responsible to apply a (G1 / G2) continuous curve to it to get the pulsating effect you want then?  In other words, do the min/max of the axis have to be the same or can be different?
>  behdad
> http://behdad.org/
> 
> 
> On Wed, Jan 31, 2024 at 1:45 AM Skef Iterum via mpeg-otspec <mpeg-otspec at lists.aau.at> wrote:
> This is another proposal idea I can't do properly in the pre-April time 
> frame, but it's short and simple.
> 
> Imagine you're a video editor working on a cable commercial about a new 
> way to Make Lots of Money!!!  You overlay a row of dollar signs from a 
> cool variable display font and animate them to "pulse" by changing their 
> weight. Unfortunately, when you look at the result the number of slashes 
> in each dollar sign keeps changing, greatly distracting your otherwise 
> elegant and sophisticated effect.
> 
> The problem here is that doing the right thing for a given position in 
> design space isn't always the right thing for animations that change the 
> design space.
> 
> I think this distinction calls for a new registered feature tag, 
> probably 'anim', that when active avoids, undoes, or compensates for any 
> (or most) such abrupt adjustments. While this is something that could 
> always just be thrown onto 'ss15' or whatever, it would be better to 
> have a reserved name so that animation tools can leave that tag turned 
> on by default.
> 
> A registered feature tag would also indicate something by its presence 
> in a font: "we've thought about this problem". Designers might even 
> throw it into a font with no such adjustments just to advertise that it 
> is compatible with animation use.
> 
> This is a simple enough idea, but I lack the context to come up with 
> specifically what the section needs to say -- what advice to give to 
> designers. Someone closer to the design side of things would do a better 
> job. If anyone comes up with that wording but doesn't want to worry 
> about ISO header pages and such, send it to me and I'll wrap it up into 
> a proposal.
> 
> Thanks,
> Skef
> 
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