*> 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. 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