I currently have the following composable: ```@Co...

# compose

[eygraber]

I currently have the following composable:

@Composable
fun ColorPicker(
  modifier: Modifier = Modifier
) {
  BoxWithConstraints(
    modifier = modifier.aspectRatio(1F)
  ) {
    val diameter = constraints.maxWidth
    ...
  }
}

The problem is that it looks like if a user passes a Modifier to ColorPicker with size constraints, it would follow those. However, BoxWithConstraints uses the incoming constraints to size itself, not the constraints in its Modifier.

In a case like this, should I be wrapping BoxWithConstraints in a Box that uses the Modifier parameter, or is it expected that the caller of ColorPicker should wrap it in whatever layout it needs, and set the size constraints appropriately?

[Zach Klippenstein (he/him) [MOD]]

The modifier passed to a composable should, if it follows best practices, affect the constraints that that composable sees. If BoxWithConstraints isn’t doing that, it’s probably a bug

[eygraber]

Looks like I have to use requiredSize because of a fillMaxSize somewhere higher in the hierarchy. Guess I need to re-read how layout and placement works 😅

[eygraber]

@Zach Klippenstein (he/him) [MOD] any good blog posts / videos on how all the different size modifiers and measurement constraints work? This issue kind of goes against my mental model of how it should work.

Surface(
      modifier = Modifier.fillMaxSize() // bigger than 250.dp
) {
      Box(
        modifier = Modifier.size(250.dp).background(Color.Yellow)
      )
}

This results in the Box taking up the full size of the Surface. I have to use requiredSize to get the behavior I expect. But it seems weird to me that the incoming constraints override size.

[Dan MacNeil]

Looking at the code for Surface it's actually just a Box with propagateMinConstraints set to true.

[Zach Klippenstein (he/him) [MOD]]

size actually used to be defaultSize or something, and requiredSize was just called size. I don’t remember why they changed. In this case, i would probably use wrapContentSize before your size modifier to be able to control alignment.

[eygraber]

Any chance of that ever getting reverted? I looked at the source, and based on how it works, I think it would make more sense to be called preferredSize (which is actually what the kdoc calls it).

[Zach Klippenstein (he/him) [MOD]]

These are stable apis now and this decision was made very intentionally. It’s not going back, for better or worse

[eygraber]

Any insight into what the factors leading to the decision were?