Set CEF to light or dark mode at runtime

[atp15]

Is there a way to send a message to CEF to tell it whether to be in light mode or dark mode so I can tell it whether it should respond to `prefers-color-scheme: light` or `prefers-color-scheme: dark` css rules?

We're adding a dark mode to our application with three settings that can be changed at runtime - light, dark and automatic where it uses the Windows theme setting. I've found it works correctly when set to automatic as Chromium automatically picks up the setting from Window. Unfortunately, this means that if the user has chosen a mode different from their Windows settings, it doesn't match. It would be good if I could send a message to CEF to tell it the which setting to use.

[magreenblatt]

With Chrome runtime you can potentially configure this using themes. See https://support.google.com/chrome/answe ... ktop&oco=2

You would need to identify what preference that equates to (load https://tests/preferences in cefclient).

[magreenblatt]

More details in https://github.com/chromiumembedded/cef ... 1894222895

[atp15]

For now, as an alternative, is there an easy way I can loop through all the CEF windows in the application and inject a CSS class?

[KatrinaS]

Get the Frame(s) throw a bunch of styles / CSS class in a String at it, or replace the href of the stylesheet,, both using ExecuteJavaScript
Untested but along the lines of :

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document.styleSheets[0].href='somestyles.css';

Or inject :

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const astyleelement=document.createElement('style');blah;blah;blah;document.head.appendChild(astyleelement);

Or inject a script Element referring to an external JavaScript file containing a single function and say call it :

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myDarkMode();

And that way you remove the hardcoded styles from your code and only have to tweak the external Function,, but regardless of what you throw at it, it *should* just all update

[atp15]

Thanks for your reply.
What I was more wondering was does CEF provide a convenient way of getting all the CEF browser windows so I use a for loop and then ExecuteJavaScript on them?

[KatrinaS]

I should think so, seems like something in browser_host_base.cc seems to provide a list that can eventually give you individuals, something like anyway

[KatrinaS]

Oh. Of course if you are creating the Clients / Frames / abstract whatever's why aren't you keeping a list of um