On Friday, October 22, 2021 at 10:19:44 PM UTC+2 Fernando Serboncini wrote:

> [coming from the other thread... :) ]
>
> +1 to what David said. It doesn't seem that returning dynamic-range: high 
> right now would be useful.
>
> The spec could use some clarification:
> - clarify if those criterias need to be supported on different conditions: 
> CSS, images, canvas, ...
> - clarify if the criterias need to be supported for both with/without 
> alpha (afaik there may be implementation differences there, but I may be 
> wrong here).
> - I wonder if the definitions of high contrast/peak brightness should 
> match the industry definitions for HDR displays? I'm not an expert, but I 
> know those exist. 
> I think it's potentially okay to ignore those definitions, but I'd ask for 
> a rationale here.
>
> I think it's a great thing to summarize hdr into a single media query, but 
> the risk here would be to release a semantic that guarantees very little, 
> and therefore is not useful in the long run.
>
>
> On Fri, Oct 22, 2021 at 10:04 AM David Baron <[email protected]> wrote:
>
>> 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
>>>
>>>
David - I'm likely missing something here, but I thought (based on this 
thread 
<https://groups.google.com/a/chromium.org/g/blink-dev/c/epSTNPYkLIs/m/o5l7pZk1AwAJ>)
 
that we do have wide-gamut support in CSS, HTML and Canvas.
Are you saying we don't support this due to lack of color level 4 support? 
Or something else?

I also didn't interpret the spec as saying anything about gamut (but rather 
about color depth <https://www.w3.org/TR/mediaqueries-5/#color>), although 
it may be possible that wide gamuts and high color depth correlate 1:1. Can 
you clarify if that's what you meant?
 

> , 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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>>>>> .
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> To view this discussion on the web visit 
>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAG0MU3gbBzJUttDWuWDRFWnP-w7%3DP4G7TrBPJiU%3DyizEH2%2Bz_Q%40mail.gmail.com
>>  
>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAG0MU3gbBzJUttDWuWDRFWnP-w7%3DP4G7TrBPJiU%3DyizEH2%2Bz_Q%40mail.gmail.com?utm_medium=email&utm_source=footer>
>> .
>>
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