Dark mode "greyness" changes if you change desktop wallpaper

[Ploki]

I just noticed that if i move a window to desktop2 which has a blue background (as opposed to more sepia desktop1), everything dark gets a blue tint.

If i change accent colour from any color to "grey", this behaviour stops.

so weird, i cant find any documentation about this.

 

[Fuchal]

WWDC18 - Videos - Apple Developer

developer.apple.com

One thing that all three of these windows had in common was that the chrome remained dark and became secondary to the content area. And Dark Mode kind of achieves this using a feature that we call desktop tinting, which causes the window's background colors to camouflage themselves with the desktop picture. We found that completely desaturated gray colors have a tendency to have a color temperature that was sometimes in conflict with what your desktop picture was, and this effect was magnified when you have a translucent sidebar area, for example, against a solid opaque area of your window, and so desktop tinting helps mitigate that. Once applied, the desktop tinting gives the whole window a harmonious color scheme, which helps it to blend in with the surrounding areas and really reduces that color temperature disparity.

So, how do we do the desktop tinting effect? The first thing that we do is, actually, we take a sample of the desktop portion that is behind the window, and then we derive a average color for that area, and then we blend that average color with a gray, which then becomes the window background color. This background color is dynamic, so as the user moves the window around the screen, the color will update itself so that the window always stays in sync with the wallpaper portion that was behind it.

 

[Ploki]

so it is documented, just not in plain sight. Thanks.

it's not really obvious except when moving windows around