On 5/18/26 4:11 p.m., Florin Malita wrote:
*Contact emails*
[email protected], [email protected], [email protected],
[email protected]
*Explainer*
https://github.com/fserb/canvas2D/blob/master/spec/enhanced-textmetrics.md
https://github.com/Igalia/explainers/blob/main/canvas-formatted-text/text-metrics-additions.md
https://github.com/whatwg/html/issues/10677
*Specification*
https://github.com/whatwg/html/pull/11000
*Summary*
Expand the TextMetrics Canvas API to support selection rectangles,
bounding box queries, and glyph cluster-based operations. This new
functionality should enable complex text editing applications with
accurate selection, caret positioning, and hit testing. Additionally,
cluster-based rendering facilitates sophisticated text effects such as
independent character animations and styling.
*Blink component*
Blink>Canvas
<https://issues.chromium.org/issues?q=customfield1222907:%22Blink%3ECanvas%22>
*Web Feature ID*
/No information provided/
*TAG review*
https://github.com/w3ctag/design-reviews/issues/1095
*TAG review status*
Pending
*Origin Trial Name*
Enhanced Canvas TextMetrics
*Goals for experimentation*
Partners have implemented prototypes based on the available runtime
feature, with positive feedback. They are now interested in expanding
the scope, and testing the API with real users. This experiment will
provide valuable validation in real-world use scenarios, and should
help us gauge the proposed API's fitness, ergonomics, and performance.
Can you also comment on progress in the following areas?
Draft spec (early draft is ok, but must be spec-like and associated with
the appropriate standardization venue, or WICG)
TAG review (see exceptions)
signals requests
Outreach for feedback from the spec community
WPT tests
*Chromium Trial Name*
ExtendedTextMetrics
*Origin Trial documentation link*
https://github.com/Igalia/explainers/blob/main/canvas-formatted-text/text-metrics-additions.md
*WebFeature UseCounter name*
kExtendedTextMetrics
*Risks*
*Interoperability and Compatibility*
These are new features and we will get vendor agreement at WHATWG
before shipping. So minimal interop risks beyond platform-specific
metrics differences.
/Gecko/: No
signal (https://github.com/mozilla/standards-positions/issues/1144)
/WebKit/: No
signal (https://github.com/WebKit/standards-positions/issues/436)
/Web developers/: Positive Developers want the ability to animated
glyphs independendly (such as exploding sentences) and the ability to
do e.g. selection on canvas text. The proposed APIs support these use
cases and more.
/Other signals/:
*Ergonomics*
None.
*Activation*
None.
*Security*
There is always a fingerprinting concern with HTML canvas. THe new
features expose no novel fingerprinting surface (text metrics are
already a fingerprinting concern).
*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 information provided/
*Reason this experiment is being extended*
Flutter Web has provided positive initial feedback based on internal
testing. To validate the feature at scale, they require additional
time to expose it to external developers via their own experimentation
infrastructure.
The goal of this extension is to gather telemetry and feedback from
real-world applications, allowing us to identify and address any
remaining rough edges before proceeding with a formal launch.
*Ongoing technical constraints*
/No information provided/
*Debuggability*
DevTools supports querying the APIs by default.
*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
html/canvas/[element|offscreen]/text...
2d.text.measure.index-from-offset* 2d.text.measure.selection-rects*
2d.text.measure.text-clusters*
https://wpt.fyi/results/html/canvas/element/text?label=master&label=experimental&aligned&q=tentative
<https://wpt.fyi/results/html/canvas/element/text?label=master&label=experimental&aligned&q=tentative>https://wpt.fyi/results/html/canvas/offscreen/text?label=master&label=experimental&aligned&q=tentative
<https://wpt.fyi/results/html/canvas/offscreen/text?label=master&label=experimental&aligned&q=tentative>
I see there are some tests that pass in all browsers - that suggests the
test isn't working as intended?
e.g.,
https://wpt.fyi/results/html/canvas/offscreen/text/2d.text.measure.strokeTextCluster-font-change.tentative.html?label=master&label=experimental&aligned&q=tentative
<https://wpt.fyi/results/html/canvas/offscreen/text/2d.text.measure.strokeTextCluster-font-change.tentative.html?label=master&label=experimental&aligned&q=tentative>
*Flag name on about://flags*
Experimental Web Platform Features
*Finch feature name*
ExtendedTextMetrics
*Requires code in //chrome?*
False
*Tracking bug*
https://issues.chromium.org/issues/341213359
*Measurement*
UMA counters will be added for the new APIs.
*Estimated milestones*
Origin trial desktop first 144
Origin trial desktop last 149
Origin trial extension 1 end milestone 155
DevTrial on desktop 141
Origin trial Android first 144
Origin trial Android last 149
DevTrial on Android 141
*Link to entry on the Chrome Platform Status*
https://chromestatus.com/feature/5075532483657728?gate=5178855770947584
*Links to previous Intent discussions*
Intent to Prototype:
https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CADgYMVdqo4PBs4OkGqVncRizs8vtX4YtFLDcK%2BRxdYo_wnaRJQ%40mail.gmail.com
Ready for Trial:
https://groups.google.com/a/chromium.org/g/blink-dev/c/OLCCI0ExvIk
Intent to Experiment:
https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CADgYMVfC-Naw8pFVaUUPMSfW-u3kC7SMdDeHJgwU5YmSHOOeeA%40mail.gmail.com
This intent message was generated by Chrome Platform Status
<https://chromestatus.com/>.
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