Re: Updated IFT Demo

On Fri, Apr 25, 2025 at 7:25 AM Chris Lilley <chris@w3.org> wrote:

> Nice! Particularly pleased to see both CFF2 and glyf in the demo.
>
> A couple of things I noticed:
>
> On the Variable Design Space Augmentation Example page, in Firefox
> (Nightly 139.0a1) I am not seeing condensed fonts being used with IFT,
> while they are used with unicode-range. On Chrome (Canary 137.0.7144.0) the
> IFT and unicode-range renderings both use condensed.
>
Oh weird, I'll figure out what's going on and fix it.

> It would be helpful for the Simplified Chinese pages to mention in English
> what thy are showing.
> On 2025-04-24 20:50, Garret Rieger wrote:
>
> Previously we had a wasm based demo of IFT that was built on a prototype
> (non spec compliant) version of the technology. I've just upgraded that
> demo to use the latest encoder <https://github.com/w3c/ift-encoder> and
> client
> <https://github.com/googlefonts/fontations/tree/main/incremental-font-transfer> implementations,
> which are both compliant with the latest specification draft.
>
> You can find the updated demo here:
> https://garretrieger.github.io/ift-demo/
>
> Notable changes:
>
>    - Most importantly the demo is now compliant with the latest IFT
>    specification draft <https://w3c.github.io/IFT/Overview.html>.
>    - For the text samples using Roboto, the previous demo used a table
>    keyed only encoding. Now it's using a mixed (glyph and table keyed)
>    encoding. The glyph keyed segmentation was generated using the experimental
>    closure based segmenter
>    <https://github.com/w3c/ift-encoder/blob/main/docs/experimental/closure_glyph_segmentation.md>.
>    Performance (in terms of # of bytes transferred) is looking good so far.
>    - For the CJK fonts the demo extends both CFF2 (Noto Serif SC) and
>    glyf (Noto Sans SC) fonts. The prior version did not include any CFF fonts.
>    - The previous demo included an example of layout feature extension,
>    that's been removed for now as the encoder does not yet fully support that
>    use case yet. I'll be getting that added back in once I get support
>    finished in the encoder.
>
> I'm planning to make some more improvements to this over time including:
>
>    - Utilize codepoint frequency data when generating the glyph
>    segmentations for Roboto.
>    - Improvements to the encodings (such as using table keyed patch
>    preload lists).
>    - General performance improvements.
>    - Demonstration of layout feature extension.
>
> Lastly, if you're interested in more details about how the IFT encodings
> for the font are created, the demo repository contains all of the code
> necessary to generate the IFT font encodings:
> https://github.com/garretrieger/ift-demo/blob/main/Makefile
>
> --
> Chris Lilley
> @svgeesus@mastodon.scot
> Technical Director @ W3C
> W3C Technical Programming Team, Core Web Design
>
>