legacyScreenSaver - blank Preview in Monterey 12.1

Starting in Monterey 12.1 (Intel), our custom 3rd party screen saver is occasionally failing to work properly when in the Preview mode (e.g. the small sample window inside the Desktop & Screen Saver system preferences window).

If I turn on detailed logging, I see the following calls being made:

ScreenSaverView.Init ScreenSaverView.hasConfigureSheet ScreenSaverView.draw

However,

ScreenSaverView.StartAnimation ScreenSaverView.AnimateOneFrame

are never called

Oddly, this only happens when first opening the Desktop & Screen Saver window.

Because, if you:

  • start the screensaver (using the Preview button or a Hot Corner) then exit the screensaver
  • open the Screen Saver Options panel for this screensver then close it
  • switch to another screensaver then back...

Any of these actions will cause the screensaver preview to start working.

This sounds a little bit like what's beeing seen in https://github.com/JohnCoates/Aerial/issues/1190 which is a different 3rd party screensaver.

Interesting - if seems that if we set a 0.5 second timer to call StartAnimation from within the Initialize method, it works again. This is probably safe as long as your screensaver can gracefully deal with StartAnimation getting called more than once.

if we set a 0.5 second timer to call StartAnimation from within the Initialize method, it works again.

Weird. You should definitely file a bug about this. Such shenanigans should not be necessary.

Please post your bug number, just for the record.

Share and Enjoy

Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

If I can come up with a reproducible case, I will submit a FB report.

I think I'm now seeing the problem with Apple screensavers as well. If anyone can try this test, I'd appreciate it:

Test 1:

  • Open System Prefernces / Desktop & Screen Saver
  • Select the "Message" screensaver
  • Click Screen Saver Options and enter some text to display "foobar"
  • Result: the apple logo and text are displayed.

Test 2:

  • Close System Prefernces
  • Open System Prefernces / Desktop & Screen Saver
  • Result: although the Message screensaver is selected, the Preview is now blank
  • If you click Screen Saver Options and then Cancel, the Preview now shows up

Repeating the test with the "Hello" screensaver does not show the bug.

Here's what I see when it's not working, and I can reproduce this issue on 3 different 12.1 systems (M1 and Intel):

Submitted as FB9835060

This bug is still present in 12.2 release version (Silicon and Intel).

I am no longer seeing this issue in the first beta of macOS 13 Ventura (22a5266r)

legacyScreenSaver - blank Preview in Monterey 12.1
 
 
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