LGTM2 On Wed, Mar 25, 2026 at 11:26 AM Philip Jägenstedt <[email protected]> wrote:
> LGTM1, I think this is a very straightforward case given that it's already > supported in Firefox and Safari. Thank you for verifying that locally and > adding the tests to WPT! > > On Wed, Mar 25, 2026 at 10:45 AM Dominik Röttsches <[email protected]> > wrote: > >> Philip asked me a few questions, here are the details: >> >> Tests: >> >> The new WPT tests are in the CL: https://crrev.com/c/7692195 >> These are newly added to WPT, but have been manually verified in Firefox >> on Linux and Safari on Mac and confirmed to show behavior that indicates >> full support for Avar2. >> >> Signals: >> >> *Web developers*: Positive >> >> >> This should be "Neutral" instead. I filled this field initially, but then >> moved to comment on >> >>> Google Fonts as an internal stake holder is keen on having this feature >>> available on the web for optimising future fonts. >> >> >> To "Other Signals", as we would not count Google Fonts under "Web >> Developers". >> >> >> >> On Tue, Mar 24, 2026 at 4:27 PM Dominik Röttsches <[email protected]> >> wrote: >> >>> *> Specification* >>> > https://www.iso.org/standard/87621.html >>> >>> As for specification details, avar2 is part of the draft of the 5th >>> edition draft, ISO/IEC FDIS 14496-22 . >>> https://www.iso.org/standard/87621.html in Section 7.3.1. avar. >>> >>> On Tuesday, March 24, 2026 at 3:57:03 PM UTC+2 [email protected] wrote: >>> >>>> *Contact emails* >>>> [email protected] >>>> >>>> *Explainer* >>>> https://github.com/harfbuzz/boring-expansion-spec/blob/main/avar2.md >>>> >>>> *Specification* >>>> https://www.iso.org/standard/87621.html >>>> >>>> *Summary* >>>> Version 2 of the avar (Axis Variations) table enables font designers to >>>> create variable fonts with better control over interpolation. While the >>>> original variable font spec handles axes independently, avar2 allows axes >>>> to influence one another. >>>> >>>> This leads to fonts that are easier to use for content authors to use, >>>> and enable compact storage. >>>> >>>> Support for this feature in Blink means at the core, activating a >>>> compile flag in HarfBuzz that processes the version 2 additional fields of >>>> the avar table to extend axis variations processing. >>>> >>>> Avar2 works by using the same familiar concepts of font variations, but >>>> applying the variable delta values to the design axis specifications >>>> itself. Plus, it allows doing this over a range of multiple axes. >>>> >>>> As an example, it allows the creation of "meta sliders" which control >>>> multiple variation axes at once, alleviating the user from fine-tuning and >>>> finding a useful corner of the font's design space. >>>> >>>> Avar2 gives font designers better control over the usable variation >>>> space of their font, and allows coordinating the adjustment of design axes >>>> across several axes. By defining the relationships between axes >>>> mathematically within the avar version 2 table, fonts can achieve complex >>>> designs with fewer masters, leading to smaller file sizes, because the >>>> interpolation is stored more efficiently. >>>> >>>> *Blink component* >>>> Blink>Fonts >>>> <https://issues.chromium.org/issues?q=customfield1222907:%22Blink%3EFonts%22> >>>> >>>> *Web Feature ID* >>>> font-variation-settings >>>> <https://webstatus.dev/features/font-variation-settings> >>>> >>>> *Motivation* >>>> Provide interoperability for this new feature of the of the Open Font >>>> Format font standard. >>>> >>>> *Initial public proposal* >>>> *No information provided* >>>> >>>> *TAG review* >>>> Not needed, as it is not a W3C spec, but ISO/OFF spec. >>>> >>>> *TAG review status* >>>> Not applicable >>>> >>>> *Goals for experimentation* >>>> None >>>> >>>> *Risks* >>>> >>>> >>>> *Interoperability and Compatibility* >>>> Low, Safari and FireFox have shipped the feature. The change to add >>>> this feature adds WPT tests that perform basic interop tests which Safari >>>> and FireFox seem to handle correctly. >>>> >>>> *Gecko*: Shipped/Shipping Tests show that avar2 support is present in >>>> FireFox. Shaping and glyph variations work (tested on Linux). >>>> >>>> *WebKit*: Shipped/Shipping Tests show that Safari ships avar2 by means >>>> of support in the OS' CoreText libraries. Avar2 shaping and glyph >>>> variations work. >>>> >>>> *Web developers*: Positive >>>> >>>> *Other signals*: Google Fonts as an internal stake holder is keen on >>>> having this feature available on the web for optimising future fonts. >>>> >>>> *Activation* >>>> With the avar2 font-tech feature definition in >>>> https://drafts.csswg.org/css-fonts-5/#font-technologies-formats it is >>>> possible for authors to implement graceful degradation. Only if the UA >>>> understands the technology(avar2) attribute, it would load and use such a >>>> font. >>>> >>>> *Security* >>>> We pass all avar2 web fonts to Fontations, which actually increases >>>> security over using system rasterizers. >>>> >>>> *WebView application risks* >>>> >>>> Does this intent deprecate or change behavior of existing APIs, such >>>> that it has potentially high risk for Android WebView-based applications? >>>> No specific WebView risks. >>>> >>>> >>>> *Debuggability* >>>> Not applicable here, DevTools does not descend into sub features of >>>> Open Font Format or OpenType fonts and their activation. >>>> >>>> *Will this feature be supported on all six Blink platforms (Windows, >>>> Mac, Linux, ChromeOS, Android, and Android WebView)?* >>>> Yes >>>> >>>> *Is this feature fully tested by web-platform-tests >>>> <https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md>?* >>>> Yes >>>> Covered by several WPT tests added as part of enabling avar2. >>>> >>>> *Flag name on about://flags* >>>> *No information provided* >>>> >>>> *Finch feature name* >>>> *No information provided* >>>> >>>> *Non-finch justification* >>>> It is not possible to have a cleanly isolating RuntimeEnabledFeature >>>> flag for the launch of this feature. The tech(avar2) support can be gated, >>>> which controls whether the UA selects an avar2 font if it is tagged as >>>> such. >>>> HarfBuzz (where shaping support for avar2 is implemented) only allows >>>> this as a compile time feature. Fontations (where glyph rendering support >>>> for avar2 is implemented) has no switch and we were already shipping glyhph >>>> variant support for this feature when switching to Fontations. >>>> >>>> *Rollout plan* >>>> Will ship enabled for all users >>>> >>>> *Requires code in //chrome?* >>>> False >>>> >>>> *Tracking bug* >>>> https://crbug.com/40246300 >>>> >>>> *Measurement* >>>> Blink.Fonts.VariableFontsRatio metric measures different font format's >>>> instantiation ratios. This covers avar2 and shows the proportion of avar2 >>>> fonts among all web fonts. >>>> >>>> *Availability expectation* >>>> Across browsers. >>>> >>>> *Estimated milestones* >>>> Shipping on desktop 148 >>>> Shipping on Android 148 >>>> Shipping on WebView 148 >>>> >>>> *Anticipated spec changes* >>>> >>>> Open questions about a feature may be a source of future web compat or >>>> interop issues. Please list open issues (e.g. links to known github issues >>>> in the project for the feature specification) whose resolution may >>>> introduce web compat/interop risk (e.g., changing to naming or structure of >>>> the API in a non-backward-compatible way). >>>> *No information provided* >>>> >>>> *Link to entry on the Chrome Platform Status* >>>> https://chromestatus.com/feature/5169590743203840?gate=6513397493530624 >>>> >>>> This intent message was generated by Chrome Platform Status >>>> <https://chromestatus.com/>. >>>> >>> -- >> You received this message because you are subscribed to the Google Groups >> "blink-dev" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To view this discussion visit >> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAN6muBupFz-R1R%2BkW4dB0M74dS4AV%3D%3DZppQkP3H147DJ6itUwA%40mail.gmail.com >> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAN6muBupFz-R1R%2BkW4dB0M74dS4AV%3D%3DZppQkP3H147DJ6itUwA%40mail.gmail.com?utm_medium=email&utm_source=footer> >> . >> > -- > You received this message because you are subscribed to the Google Groups > "blink-dev" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion visit > https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAARdPYd9asP9WNk9M_DD95Wc6ghBMp%2B%2B1sp7KxN%2BMdx4JuvGhA%40mail.gmail.com > <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAARdPYd9asP9WNk9M_DD95Wc6ghBMp%2B%2B1sp7KxN%2BMdx4JuvGhA%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "blink-dev" group. 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