Android wallpaper fingerprints

Posted Oct 28, 2021 14:11 UTC (Thu) by immibis (subscriber, #105511)
In reply to: Android wallpaper fingerprints by syrjala
Parent article: Android wallpaper fingerprints

And how are those widgets implemented? Either in-process - in which case you can just get access to them - even if they are protected by Java mechanisms you can scan memory with native code. Or out-of-process - in which case your opportunities for UI customization are severely limited. And you have to restrict the app from taking screenshots of itself!

Android wallpaper fingerprints

Posted Oct 28, 2021 15:31 UTC (Thu) by dskoll (subscriber, #1630) [Link] (4 responses)

Why would most apps need to take screenshots of themselves?

Android wallpaper fingerprints

Posted Oct 28, 2021 15:47 UTC (Thu) by immibis (subscriber, #105511) [Link]

I dunno, some kind of picture-in-picture or other postprocessing effect. I know there are some games that screenshot themselves for the pause screen background, but that's not on Android. The point is that you'd generally expect apps to be able to read their own pixels. Changing that will probably break something.

IIRC Android apps work by sending screenfuls of pixels to the compositor process. How will you stop them seeing what they're sending?

Android wallpaper fingerprints

Posted Oct 28, 2021 23:38 UTC (Thu) by derobert (subscriber, #89569) [Link] (2 responses)

One example, Firefox's tab chooser shows what each tab looks like. Easiest way to implement that is of course to just scale down the pixels that were displayed.

Android wallpaper fingerprints

Posted Oct 30, 2021 8:59 UTC (Sat) by mkbosmans (subscriber, #65556) [Link] (1 responses)

Sure, but in that analogy the browser is the toolkit and whatever is running inside the tab is the app. So the app itself does not need to know the pixel output.

Android wallpaper fingerprints

Posted Oct 30, 2021 9:15 UTC (Sat) by derobert (subscriber, #89569) [Link]

That's not an analogy; Firefox is an Android app (as well as desktop of course). It also happened to be the app I was using at the moment (to read LWN).