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The app doesn't know. It just produces a widget tree, and the OS-provided renderer renders it this way or that way. In particular, it chooses not to render cont
by nine_k 2mo ago
The app doesn't know. It just produces a widget tree, and the OS-provided renderer renders it this way or that way. In particular, it chooses not to render controls marked as "security-sensitive" when the rendering is intended for a screenshot; it could instead put empty boxes in their place, etc. The app has no idea and no control, AFAIK.
- kashnote 2mo agoDon't apps like Snapchat notify the other person if you take a screenshot of your messages?
- Petersipoi 2mo agoYes, Snapchat does this. Apps absolutely have the ability to know when a screenshot is taken.
- thaumasiotes 2mo agoSnapchat advertises that they detect screenshots. They try. But they're well aware that they can't actually know. For example, their bug bounty program policy helpfully informs you that "screenshot detection avoidance" is not considered a vulnerability: https://hackerone.com/snapchat https://hackerone.com/snapchat . That's because it's always possible.
- woadwarrior01 2mo agoYes, iOS has userDidTakeScreenshotNotification for that. https://developer.apple.com/documentation/uikit/uiapplication/userdidtakescreenshotnotification https://developer.apple.com/documentation/uikit/uiapplicatio...
- retired 2mo agoWould be nice if the user could disable that.
- mylies43 2mo agoI think at least in snap it makes sense, the communications are suppose to be ethereal and disappear after reading, I like to know when someone screenshots something and its no longer ethereal
- woadwarrior01 2mo agoThere's an unspecified short/random delay between the user taking the screenshot and the notification firing. The trick used by Bluesky, Telegram etc is using a different technique. They (mis)use secure input fields to show an overlay when the user takes a screenshot.
- nemosaltat 2mo agoThe apps definitely know. Horsemen example: If you screenshot on Amazon (and Business version) iOS apps, it “helpfully” pops its own share sheet.
- saghm 2mo agoEven having never developed on iOS before, I was able to find this in the first google search result for "ios api to detect screenshot": https://developer.apple.com/documentation/uikit/uiapplication/userdidtakescreenshotnotification https://developer.apple.com/documentation/uikit/uiapplicatio...
- monegator 2mo agoOpen the amazon app. Take a screenshot. See a toast message informing you that the amazon app has detected you've taken a screenshot. Fucking used for fucking profiling.