On Thu, Apr 20, 2023 at 12:30 PM Stephen Chenney <schen...@chromium.org> wrote:
> Back to the testing question. There are hundreds of blink web tests that > set zoom via CSS. Most of them are not testing the zoom CSS feature itself > (though some are) so most of them would need to be updated to test browser > zoom situations. It's tractable, particularly if we modify the existing > testing internals methods to enable arbitrary zoom. > > While we're at it, I propose adding testing functionality to WPT for > testing at different device scale factors. As far as I can tell it does not > yet exist. > > Is that step 1a? Step 0? > Sorry for forgetting to reply to your email. These can be fixed by replacing zoom on the root element with an Internals method that does the same thing without a CSS property. The ones that set non-root zooms I plan to delete. > On Thu, Apr 20, 2023 at 3:01 PM Alex Russell <slightly...@chromium.org> > wrote: > >> I agree that this is probably too risky right now. Are you willing to >> modify the plan you posted to gate #4 on a UKM analysis and/or driving use >> below a negotiated threshold, Chris? >> >> Thanks, >> >> Alex >> >> On Thursday, April 20, 2023 at 11:15:32 AM UTC-7 Chris Harrelson wrote: >> >>> Comments below, but here is a concrete shipping plan proposal: >>> >>> 1. Blog post describing what is happening, why, and how to fix your code. >>> 2. Start a deprecation for 3 milestones (M114-116), with a devtools >>> console warning. Notify enterprises and webview clients of the deprecation. >>> 3. In parallel with #2: turn it off now via finch for canary/dev, then >>> later beta, to see if we get bug reports. >>> 4. Assuming no bug reports that raise new concerns, ship the change in >>> M117. >>> >>> On Thu, Apr 20, 2023 at 9:01 AM Rick Byers <rby...@chromium.org> wrote: >>> >>>> On Wed, Apr 19, 2023 at 6:53 PM Chris Harrelson <chris...@chromium.org> >>>> wrote: >>>> >>>>> Mike said: *"It would also be good to go through all duplicates and >>>>> "See Also" bugs linked at >>>>> https://bugzilla.mozilla.org/show_bug.cgi?id=390936 >>>>> <https://bugzilla.mozilla.org/show_bug.cgi?id=390936> and see how we fare >>>>> with a build that has zoom disabled."* >>>>> >>>>> Good idea. I checked all 37 of the sites referenced from that issue. I >>>>> found only 3 that were even somewhat broken, and only 2 where there was >>>>> something substantial (an "8-ball" image that was too big, and a facebook >>>>> login that was cut off at some viewport sizes). Most sites didn't have any >>>>> zoom at all. >>>>> >>>>> I also updated the "use cases" section with more use cases found by >>>>> reviewing the sites. >>>>> >>>>> Yoav said:* "Is it possible to also expose the usecounter as UKM, and >>>>> see the usage distribution? Given the high usage percentage, it can be >>>>> reassuring to see that a) No large sites get broken by this b) Long tail >>>>> sampling from UKM matches what y'all saw in HA"* >>>>> >>>>> It's possible. Based on the data I've provided (including response to >>>>> Mike above), do you think it's needed? >>>>> >>>>> On Mon, Apr 17, 2023 at 2:39 PM Rick Byers <rby...@chromium.org> >>>>> wrote: >>>>> >>>>>> >>>>>> First, you'll have a flag so we can kill-switch it if we see any >>>>>> non-trivial breakage in practice, right? >>>>>> >>>>> >>>>> Already in place. CSSZoom is a base::Feature in addition to a >>>>> RuntimeEnabledFeature. >>>>> >>>>> >>>>>> WebView seems particularly risky, perhaps we should separate that out >>>>>> and leave it enabled on WebView at least to start? >>>>>> >>>>> >>>>> I'm willing to do that as a first step. >>>>> >>>>> >>>>>> What about enterprise, likely to be higher risk / needing a >>>>>> mitigation strategy? >>>>>> >>>>> >>>>> I'll add an enterprise flag for it, and ask for this change to be >>>>> highlighted in enterprise release notes. WDYT, good enough? >>>>> >>>> >>>> Works for me. >>>> >>>> From the HA analysis, were you able to get any upper bound on the >>>>>> fraction of sites with significant (i.e. usability impacting) breakage? >>>>>> Eg. >>>>>> can we spot check 100 pages that hit the counter to see if any look >>>>>> really >>>>>> broken? Alternately the UKM analysis Yoav suggests could help. I've been >>>>>> planning on figuring out how to do a UKM usage distribution analysis - >>>>>> this >>>>>> might make a good candidate. >>>>>> >>>>> >>>>> I spot checked 62 sites from HTTPArchive and from the Mozilla bug. In >>>>> my view, none were terribly broken, and almost all were unaffected or had >>>>> trivial changes. According to foolip's methodology >>>>> <https://sample-size.net/confidence-interval-proportion/> with N=62 >>>>> and x=0, that means that we've reduced the risk from the use counter of >>>>> 0.5% to 0.028%. >>>>> >>>>> To get to 0.001% I'd need a lot more N, technically speaking. >>>>> >>>>> However, in basically all of the cases zoom was applied either to very >>>>> few elements or to the body; in the latter the site still renders fine >>>>> (because browser zoom uses the same technique), and for the others it's at >>>>> best cosmetic in almost all cases. >>>>> >>>> >>>> That's great to hear. Given the usage is pretty high and there's at >>>> least some uncertainty among developers with how to replace their use of >>>> zoom (Christoph's note), WDYT about doing a blog post warning about the >>>> removal of zoom and showing how to replace it with transforms? >>>> >>> >>> Sure, I can do that. Note that some sites already put -moz-transform and >>> zoom in their style sheet, so there is evidence that transform works ok for >>> some use cases. >>> >>> >>>> >>>> Also, should we consider a deprecation period with deprecation warnings >>>> in the console and available to the reporting API? Or is that likely to be >>>> so noisy with most cases being false positives that it would be net harmful >>>> do you think? >>>> >>> >>> A deprecation period makes sense. (Note that Firefox already has >>> warnings in their devtools not to use this feature.) >>> >>> >>>> >>>>> On Mon, Apr 17, 2023 at 4:55 PM Morten Stenshorne < >>>>>> msten...@chromium.org> wrote: >>>>>> >>>>>>> Chris Harrelson <chris...@chromium.org> writes: >>>>>>> >>>>>>> > On Sun, Apr 16, 2023 at 11:45 PM Morten Stenshorne < >>>>>>> msten...@chromium.org> wrote: >>>>>>> > >>>>>>> > Chris Harrelson <chris...@chromium.org> writes: >>>>>>> > >>>>>>> > > On Fri, Apr 14, 2023 at 5:09 PM PhistucK <phist...@gmail.com> >>>>>>> wrote: >>>>>>> > > >>>>>>> > > Any alternatives? I thought there was a section in the intent >>>>>>> templates for that... >>>>>>> > > >>>>>>> > > One alternative for the use case mentioned in my earlier email >>>>>>> is to >>>>>>> > > apply a CSS transform instead. This will magnify the subtree >>>>>>> visually >>>>>>> > > but not cause a zoom-style layout change. >>>>>>> > >>>>>>> > The fact that a CSS transform doesn't affect layout, whereas >>>>>>> 'zoom' >>>>>>> > does, means that we'll paginate (fragment) properly with 'zoom', >>>>>>> but not >>>>>>> > with transforms, since they are applied after fragmentation [1], >>>>>>> causing >>>>>>> > content to be sliced across fragmentainer boundaries, and the >>>>>>> actual >>>>>>> > page/column breaks (as far as layout is concerned) are shifted >>>>>>> away from >>>>>>> > the fragmentainer edges visually, and will appear in the middle >>>>>>> of a >>>>>>> > page/column, for instance. >>>>>>> > >>>>>>> > [1] https://www.w3.org/TR/css-break-3/#transforms (never mind the >>>>>>> > example there; it's not too relevant for this discussion, but I >>>>>>> can >>>>>>> > provide one if you want) >>>>>>> > >>>>>>> > Agreed that this is a difference. If a developer wants the result >>>>>>> to >>>>>>> > flow through fragmentation, they'll have to use the second >>>>>>> alternative >>>>>>> > I suggested. >>>>>>> > >>>>>>> > But in terms of web compat, I don't think this situation is >>>>>>> anything >>>>>>> > to worry about (e.g. I didn't see any fragmentation when reviewing >>>>>>> 25 >>>>>>> > random sites linked to from chromestatus.com). >>>>>>> >>>>>>> But as soon as someone prints any of those sites, there'll be >>>>>>> fragmentation. >>>>>>> >>>>>>> That said, I couldn't find anything bad on those sites, either. I was >>>>>>> thinking that if it's actually okay to replace zoom with a scale >>>>>>> transform, we really need authors to make such elements monolithic >>>>>>> (because any break point inserted inside a transformed element will >>>>>>> more >>>>>>> likely than not end up in the middle of some page, rather than at an >>>>>>> actual page boundary). So I changed the engine locally to treat zoom >>>>>>> != >>>>>>> 1 as monolithic. But that didn't make any of sites that I tried look >>>>>>> any >>>>>>> worse. >>>>>>> >>>>>>> > > Another alternative is for the developer to multiply the >>>>>>> numbers in >>>>>>> > > their CSS properties via calc + variables. >>>>>>> > >>>>>>> > That alternative should always work, but more cumbersome for the >>>>>>> > authors, I suppose? >>>>>>> > >>>>>>> > Yes, a bit more cumbersome, but interoperable across all browser >>>>>>> engines. >>>>>>> > >>>>>>> > >>>>>>> > > On Sat, Apr 15, 2023 at 1:03 AM Chris Harrelson < >>>>>>> chris...@chromium.org> wrote: >>>>>>> > > >>>>>>> > > Contact emails >>>>>>> > > >>>>>>> > > chris...@chromium.org >>>>>>> > > >>>>>>> > > Specification >>>>>>> > > >>>>>>> > > https://developer.mozilla.org/en-US/docs/Web/CSS/zoom >>>>>>> > > >>>>>>> > > Summary >>>>>>> > > >>>>>>> > > Removes support for the non-standard "zoom" CSS property. This >>>>>>> CSS property causes computed lengths for an element to be multiplied by >>>>>>> > > the specified zoom factor. >>>>>>> > > >>>>>>> > > Blink component >>>>>>> > > >>>>>>> > > Blink>CSS >>>>>>> > > >>>>>>> > > TAG review >>>>>>> > > >>>>>>> > > None >>>>>>> > > >>>>>>> > > TAG review status >>>>>>> > > >>>>>>> > > Not applicable >>>>>>> > > >>>>>>> > > Risks >>>>>>> > > >>>>>>> > > Interoperability and Compatibility >>>>>>> > > >>>>>>> > > This feature is only available in Webkit and Blink-based >>>>>>> browsers, and has been present in Chrome since the beginning. Usage is a >>>>>>> little above >>>>>>> > > 0.5% of page loads: >>>>>>> https://chromestatus.com/metrics/feature/timeline/popularity/3578 >>>>>>> However, research shows that sites in HTTPArchive >>>>>>> > > triggering the feature mostly don't even seem to use it, and >>>>>>> those that do appear to always use it in a way that works fine without >>>>>>> zoom >>>>>>> applied >>>>>>> > > - worst case, just a very minor change to the size of a tiny >>>>>>> number of UI elements, but the UX is basically the same. See: >>>>>>> > > >>>>>>> https://docs.google.com/document/d/1cmbXpjAcXAht2ufi7bNKy-rbVNveqaf0UzeYg_DIMNA/edit# >>>>>>> > > >>>>>>> > > Gecko: Shipped/Shipping (Firefox never supported the feature.) >>>>>>> > > >>>>>>> > > WebKit: No signal ( >>>>>>> https://github.com/WebKit/standards-positions/issues/170) >>>>>>> > > >>>>>>> > > Web developers: Some web developers like the feature, in >>>>>>> particular for the use case of zooming in content in a legible way with >>>>>>> responsive >>>>>>> > > design. See comments regarding that in this issue; >>>>>>> https://github.com/w3c/csswg-drafts/issues/5623 >>>>>>> > > >>>>>>> > > Other signals: The CSSWG has decided to not specify this >>>>>>> feature: https://github.com/w3c/csswg-drafts/issues/5623 >>>>>>> > > >>>>>>> > > Ergonomics >>>>>>> > > >>>>>>> > > See "other views" section. >>>>>>> > > >>>>>>> > > Activation >>>>>>> > > >>>>>>> > > N/A >>>>>>> > > >>>>>>> > > Security >>>>>>> > > >>>>>>> > > None >>>>>>> > > >>>>>>> > > 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? >>>>>>> > > >>>>>>> > > Maybe. WebView-based apps might use this feature. >>>>>>> > > >>>>>>> > > Debuggability >>>>>>> > > >>>>>>> > > Sites should be able to see that zoom no longer applies to >>>>>>> elements in devtools, though there is no warning planned. >>>>>>> > > >>>>>>> > > Will this feature be supported on all six Blink platforms >>>>>>> (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)? >>>>>>> > > >>>>>>> > > Yes >>>>>>> > > >>>>>>> > > Is this feature fully tested by web-platform-tests? >>>>>>> > > >>>>>>> > > No >>>>>>> > > >>>>>>> > > Flag name >>>>>>> > > >>>>>>> > > CSSZoom >>>>>>> > > >>>>>>> > > Requires code in //chrome? >>>>>>> > > >>>>>>> > > False >>>>>>> > > >>>>>>> > > Sample links >>>>>>> > > >>>>>>> > > https://output.jsbin.com/yimuwax >>>>>>> > > >>>>>>> > > Estimated milestones >>>>>>> > > >>>>>>> > > Shipping on desktop 114 >>>>>>> > > DevTrial on desktop 114 >>>>>>> > > >>>>>>> > > Shipping on Android 114 >>>>>>> > > DevTrial on Android 114 >>>>>>> > > >>>>>>> > > Shipping on WebView 114 >>>>>>> > > >>>>>>> > > 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). >>>>>>> > > >>>>>>> > > None >>>>>>> > > >>>>>>> > > Link to entry on the Chrome Platform Status >>>>>>> > > >>>>>>> > > https://chromestatus.com/feature/6535859207143424 >>>>>>> > > >>>>>>> > > Links to previous Intent discussions >>>>>>> > > >>>>>>> > > This intent message was generated by Chrome Platform Status. >>>>>>> > > >>>>>>> > > -- >>>>>>> > > 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 blink-dev+unsubscr...@chromium.org. >>>>>>> > > To view this discussion on the web visit >>>>>>> > > >>>>>>> > >>>>>>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAOMQ%2Bw_2izF%2BTzHvALsKSxD_uLds%2BPAD7fLtvpX4Cwe7sTwU7g%40mail.gmail.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 blink-dev+unsubscr...@chromium.org. >>>>>>> > > To view this discussion on the web visit >>>>>>> > > >>>>>>> > >>>>>>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CABc02_%2Br8k-q-bKWGFKxgNbSy97UKGf7VUSMnrnURBJHor-x_w%40mail.gmail.com >>>>>>> . >>>>>>> > >>>>>>> > >>>>>>> > -- >>>>>>> > Morten Stenshorne, Software developer, >>>>>>> > Blink/Layout, Google, Oslo, Norway >>>>>>> > >>>>>>> > -- >>>>>>> > 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 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