Black about:blank page for dark themed OSes

[Kazimierzw-Google]

• Reason for change:

  • enhanced UX for users having dark themed OS,
  • potential power efficiency gain.

• Relevant spec section

---

CC: @wojtas-marcin

[eligrey]

Since you mentioned it, should power efficiency be considered here? E.g. Browsers could only use a black background for about:blank if the system is in dark mode AND the display device that the page is being presented on is self-emissive.

Displaying black takes more energy on LCD devices that don't support local dimming.

[Kazimierzw-Google]

Interesting point, Eli!

How about we keep both change reasons, discuss the validity of the request and then decide holistically taking into account all arguments?

[Kazimierzw-Google]

Anyone?

[tabatkins]

You linked to the general default CSS for pages, particularly the idea that the canvas background is white by default, but your issue title is specifically about about:blank. Did you mean to scope your request to just that particular URL? Or were you intending to talk about pages in general?

If the latter, this is already covered by the Color Adjust spec - in dark mode, the canvas should be dark-colored as well. (The spec is intentionally vague about what precisely this means, but in practice it's that the canvas is painted with the canvas color, which is white in light mode and black in dark mode. The color property is more explicit that its initial value matches the canvastext color, which is the inverse.)