Re: Adding support for HDR headroom in ScreenDetailed

FWIW, I generally support enhancing ScreenDetails with HDR info about the
display.
Chris, can you add a simple example in the explainer, showing how
this resolves web developer requirements, which are otherwise unmet?

On Tue, Jul 1, 2025 at 5:50 AM Christopher Cameron <ccameron@google..com>
wrote:

> Please let me know if there are any concerns with this proposal!
>
>
> On Mon, Jun 23, 2025 at 7:33 PM Christopher Cameron <ccameron@google.com>
> wrote:
>
>> Hello Second Screen WG (and ColorWeb-CG as FYI)!
>>
>> The HDR headroom of a screen is a core parameter for how HDR content is
>> rendered (see this description in CSS HDR
>> <https://drafts.csswg.org/css-color-hdr/#introducing-headroom>).
>> Advanced applications may want to perform custom tone mapping using this
>> parameter. This is another brick in the HDR canvas proposal
>> <https://github.com/w3c/ColorWeb-CG/blob/hdr_canvas_r2/hdr_html_canvas_element.md> that
>> has been slowly making progress.
>>
>> The short version of the proposal is: Add the screen's HDR headroom
>> parameter to ScreenDetailed. It is a potential fingerprinting vector, so
>> ScreenDetailed is a better fit than Screen. It can also fluctuate rapidly
>> (e.g, when the screen brightness changes) and independently of other screen
>> properties, and so it gets its own "on change" event, separate from the
>> other screen properties.
>>
>> Please see below for the fully fleshed out proposal:
>>
>>    - Issue <https://github.com/w3c/window-management/issues> on
>>    window-management API
>>    - PR <https://github.com/w3c/window-management/pulls> on
>>    window-management API
>>    - Explainer
>>    <https://github.com/ccameron-chromium/ColorWeb-CG/blob/screen_hdr_headroom/screen_hdr_headroom.md>
>>
>> This has been shipping behind a flag for several years (although with
>> some slight API differences, which have been ironed out to better fit the
>> CSS HDR model). Now that HDR content is getting to be much more common,
>> there have been several requests to get this out from behind the flag.
>>
>>
>>

Received on Friday, 4 July 2025 09:44:30 UTC