6 ms·

1000%. Apps should not even be able to know that I've taken a screenshot - let alone change the contents of it.

nine_k 1mo 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.
- monegator 1mo ago
  Open 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.
- kashnote 1mo ago
  Don't apps like Snapchat notify the other person if you take a screenshot of your messages?
  - Petersipoi 1mo ago
    Yes, Snapchat does this. Apps absolutely have the ability to know when a screenshot is taken.
    - thaumasiotes 1mo ago
      Snapchat 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 1mo ago
    Yes, iOS has userDidTakeScreenshotNotification for that. https://developer.apple.com/documentation/uikit/uiapplication/userdidtakescreenshotnotification https://developer.apple.com/documentation/uikit/uiapplicatio...
    - retired 1mo ago
      Would be nice if the user could disable that.
      - mylies43 1mo ago
        I 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 1mo ago
        There'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 1mo ago
  The apps definitely know. Horsemen example: If you screenshot on Amazon (and Business version) iOS apps, it “helpfully” pops its own share sheet.
- saghm 1mo ago
  Even 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...

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.

monegator 1mo ago
Open 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.
kashnote 1mo ago
Don't apps like Snapchat notify the other person if you take a screenshot of your messages?
- Petersipoi 1mo ago
  Yes, Snapchat does this. Apps absolutely have the ability to know when a screenshot is taken.
  - thaumasiotes 1mo ago
    Snapchat 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 1mo ago
  Yes, iOS has userDidTakeScreenshotNotification for that. https://developer.apple.com/documentation/uikit/uiapplication/userdidtakescreenshotnotification https://developer.apple.com/documentation/uikit/uiapplicatio...
  - retired 1mo ago
    Would be nice if the user could disable that.
    - mylies43 1mo ago
      I 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 1mo ago
        There'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 1mo ago
The apps definitely know. Horsemen example: If you screenshot on Amazon (and Business version) iOS apps, it “helpfully” pops its own share sheet.
saghm 1mo ago
Even 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...