This sounds like exactly the sort of case where an implementation should
report (dynamic-range: standard) and (video-dynamic-range: high).  It would
be great to see the spec clarified to make it clearer what UA support is
expected for each, though.

-David

On Thu, Oct 21, 2021 at 7:03 PM Will Cassella <[email protected]> wrote:

> Copying over from the other thread (trying to continue the discussion
> here):
>
> The spec <https://www.w3.org/TR/mediaqueries-5/#dynamic-range> requires
>> that "The combination of the User Agent and the output device fulfill all
>> of the following criteria" when describing what it means to be high
>> dynamic-range.  Since Chromium doesn't support wide-gamut colors in CSS,
>> HTML, or Canvas, I think it's probably incorrect to report that 
>> (dynamic-range:
>> high) is true based only on the device, which is what it looks to me
>> like the current code
>> <https://source.chromium.org/chromium/chromium/src/+/main:third_party/blink/renderer/core/css/media_query_evaluator.cc;l=351-378;drc=4d3cb20c1aebba55e54112531222c7434d29f3b0>
>>  does.
>> Admittedly, the spec could probably use some clarification as to what it
>> means for the User Agent to fulfill the criteria for both the
>> dynamic-range and video-dynamic-range queries, but my understanding of
>> what the spec is trying to say is that Chrome probably shouldn't say that 
>> (dynamic-range:
>> high) is true until it supports wide-gamut colors in at least some and
>> maybe all of those contexts.
>
>
> I think you're right that the spec needs some clarification, since we're
> trying to incrementally enable adoption of HDR on the web the intent isn't
> to signal that HDR is supported by all APIs. We do already support HDR in
> some scenarios, such as the <video> element, so having these queries exist
> to let developers detect display capabilities is already useful.
>
> On Wed, Oct 20, 2021 at 11:27 PM Yoav Weiss <[email protected]>
> wrote:
>
>>
>>
>> On Thu, Oct 21, 2021 at 7:01 AM Will Cassella <[email protected]>
>> wrote:
>>
>>> Thanks for the feedback! I've updated that section:
>>>
>>> Debuggability
>>>
>>> Styles with these media queries can be viewed and edited in the devtools
>>> frontend, albeit without proper highlighting. I've created pull requests on
>>> the relevant libraries used in the devtools frontend to enable this.
>>> https://github.com/stylelint/stylelint/pull/5613
>>> https://github.com/codemirror/CodeMirror/pull/6803
>>>
>>> On Wednesday, October 20, 2021 at 9:10:36 AM UTC-7 Mathias Bynens wrote:
>>>
>>>> On Wed, Oct 20, 2021 at 5:44 PM Will Cassella <[email protected]>
>>>> wrote:
>>>>
>>>>> Contact [email protected], [email protected],
>>>>> [email protected]
>>>>>
>>>>> Explainer
>>>>> Adds MediaQueries for detecting HDR vs HDR displays
>>>>> https://www.w3.org/TR/mediaqueries-5/#dynamic-range
>>>>> https://www.w3.org/TR/mediaqueries-5/#video-dynamic-range
>>>>>
>>>>> Specificationhttps://www.w3.org/TR/mediaqueries-5/#dynamic-range
>>>>>
>>>>> Summary
>>>>>
>>>>> Adds media queries to CSS which allow a page to detect the current
>>>>> display device’s support for HDR. This feature adds two new CSS media
>>>>> queries: 'dynamic-range' and 'video-dynamic-range', both of which may be
>>>>> one of 'standard' or 'high'. Chrome will resolve these queries according 
>>>>> to
>>>>> the capabilities of the display device the browser window is currently
>>>>> positioned on, allowing pages to toggle CSS rules accordingly or respond 
>>>>> in
>>>>> Javascript via 'window.matchMedia()'.
>>>>>
>>>>>
>>>>> Blink componentBlink>CSS
>>>>> <https://bugs.chromium.org/p/chromium/issues/list?q=component:Blink%3ECSS>
>>>>>
>>>>> Motivation
>>>>>
>>>>> As HDR-supported displays become more common, web developers need ways
>>>>> to enable HDR content on their web pages without compromising the
>>>>> experience for users of non-HDR displays, or mixed-HDR multi-display
>>>>> setups. CSS already provides the 'media query' concept for toggling rules
>>>>> based on display device characteristics, and this feature extends that set
>>>>> of queries to enable detecting HDR support on the current display device.
>>>>>
>>>>>
>>>>> Initial public proposal
>>>>>
>>>>> TAG reviewNot Filed. This is an incremental change to CSS Media
>>>>> Queries, already adopted by CSS WG.
>>>>>
>>>>
>> I agree a TAG review is not needed for the `dynamic-range` MQ, as it's
>> shipped in Safari and adopted by the CSSWG.
>> The video variant however doesn't meet that criteria. Was the concept of
>> `video-*` MQs discussed with the TAG? Are there other `video-*` MQs that
>> are already shipped?
>>
>>
>>>
>>>>>
>>>>> TAG review statusNot applicable
>>>>>
>>>>> Risks
>>>>>
>>>>>
>>>>> Interoperability and Compatibility
>>>>>
>>>>>
>>>>>
>>>>> Gecko: Worth prototyping (
>>>>> https://github.com/mozilla/standards-positions/issues/584)
>>>>>
>>>>> WebKit: Shipped/Shipping (
>>>>> https://webkit.org/blog/10247/new-webkit-features-in-safari-13-1/)
>>>>> Partially implemented - `video-dynamic-range` not yet supported
>>>>>
>>>>> Web developers: Positive (
>>>>> https://github.com/w3c/csswg-drafts/issues/4471#issuecomment-548085935)
>>>>> Feature designed with the help of Netflix.
>>>>>
>>>>>
>>>>> Debuggability
>>>>>
>>>>> No specific DevTools support
>>>>>
>>>>
>>>> Please follow https://goo.gle/devtools-checklist and elaborate on this
>>>> a little bit. Per the guide, we need to ensure DevTools supports basic
>>>> editing of this new media query. It looks like this works out of the box in
>>>> Canary.
>>>>
>>>>
>>>>> Is this feature fully tested by web-platform-tests
>>>>> <https://chromium.googlesource.com/chromium/src/+/master/docs/testing/web_platform_tests.md>
>>>>> ?Yes
>>>>> https://wpt.fyi/results/css/mediaqueries/dynamic-range.html
>>>>>
>>>>> Flag nameCSSDynamicRangeMediaQueries
>>>>>
>>>>> Requires code in //chrome?False
>>>>>
>>>>> Tracking bughttps://crbug.com/1224711
>>>>>
>>>>> Estimated milestones97
>>>>>
>>>>>
>>>>> Link to entry on the Chrome Platform Status
>>>>> https://chromestatus.com/feature/5680926106320896
>>>>>
>>>>> This intent message was generated by Chrome Platform Status
>>>>> <https://www.chromestatus.com/>.
>>>>>
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>>>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CA%2BF%3DP4hQtag7Ja_7HF4jRHbuC8h5-_0TzjoJvVEMHmrUeZYW9g%40mail.gmail.com?utm_medium=email&utm_source=footer>
>>>>> .
>>>>>
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>>

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