- From: Christopher Cameron <ccameron@google.com>
- Date: Thu, 31 Jul 2025 13:33:06 -0700
- To: Mike Wasserman <msw@chromium.org>
- Cc: public-secondscreen@w3.org, anssi.kostiainen@intel.com, louay.bassbouss@fokus.fraunhofer.de, fd@w3.org, public-colorweb@w3.org
- Message-ID: <CAGnfxj-pWukJZEzcdN3OCkF2QzpKDb9hsHJsTPS86GMNnKsmyw@mail.gmail.com>
Hello Second Screen WG, Let me know if you have any more thoughts on this proposal! On Wed, Jul 2, 2025 at 11:20 AM Mike Wasserman <msw@chromium.org> wrote: > Thanks, Chris, those use cases are helpful, and should resonate with folks > familiar with advanced HDR rendering. > I'm fairly naive in that regard, but enjoyed your gainmap demo's ratio > adjustment based on screen headroom queries as I moved a window between my > Macbook's internal and external displays! > I highly encourage folks to share this proposal, offer feedback, and raise > any concerns in a timely fashion, thanks! > > On Wed, Jul 2, 2025 at 4:44 AM Christopher Cameron <ccameron@google.com> > wrote: > >> Thank you! >> >> I've updated the explainer with this section >> <https://github.com/ccameron-chromium/ColorWeb-CG/blob/master/screen_hdr_headroom.md#example-use-cases> >> outlining the two main use cases (custom tone mapping, and ensuring >> accurate color grading). >> >> I actually have a bunch of demos that depend on this (in various >> prototype forms). Probably the best one is this gainmap demo >> <https://ccameron-chromium.github.io/webgl-examples/gainmap-viewer.html> (it >> requires experimental web platform features to be enabled), in which the >> custom tone mapping shader will adapt to the selected headroom (called "HDR >> to SDR ratio" in the app), which can be set automatically using this >> feature. >> >> >> >> >> >> On Tue, Jul 1, 2025 at 10:07 PM Mike Wasserman <msw@chromium.org> wrote: >> >>> 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 Thursday, 31 July 2025 20:33:21 UTC