with(LocalDensity.current) {
    window.minimumSize = Dimension(400.dp.roundToPx(), 250.dp.roundToPx())
}

Is there a way to subscribe to the local density as state so that if it changes it triggers a re-draw?

Short answer is yes.

interesting

Ah, I see. What does the re-draw look like? Is it a canvas?

Your code will already recompose when the density changes as

LocalDensity

is a

CompositionLocal

.

It doesn’t appear that it does. i.e. here is what I’m doing:

with(LocalDensity.current) {
    window.minimumSize = Dimension(400.dp.roundToPx(), 250.dp.roundToPx())
}

The minimum sizes were drastically different when I was moving between my monitors.

That means

LocalDensity.current

did change and isn't that what you want?

JFrame (ComposeWindow) is already works with scaled pixels, and should automatically react to density changes. You only need to set the minimum size at startup:

DisposableEffect(Unit) {
  window.minimumSize = Dimension(400, 250)
  onDispose {}
}