fillMaxSize

fun Modifier.fillMaxSize(@FloatRange(from = 0.0, to = 1.0) fraction: Float = 1f) =
    this.then(if (fraction == 1f) FillWholeMaxSize else FillElement.size(fraction))

Have the content fill (possibly only partially) the Constraints.maxWidth and Constraints.maxHeight of the incoming measurement constraints, by setting the minimum width and the maximum width to be equal to the maximum width multiplied by fraction, as well as the minimum height and the maximum height to be equal to the maximum height multiplied by fraction. Note that, by default, the fraction is 1, so the modifier will make the content fill the whole available space. If the incoming maximum width or height is Constraints.Infinity this modifier will have no effect in that dimension.

Parameters

Code Examples

FillHalfSizeModifier

@Composable
fun FillHalfSizeModifier() {
    Box(Modifier.requiredSize(100.dp).background(Color.Red), contentAlignment = Alignment.Center) {
        // The inner Box will be (50.dp x 50.dp).
        Box(Modifier.requiredWidth(30.dp).fillMaxSize(0.5f).background(color = Color.Magenta))
    }
}

SimpleFillModifier

@Composable
fun SimpleFillModifier() {
    Box(Modifier.fillMaxSize().background(Color.Red), contentAlignment = Alignment.Center) {
        Box(Modifier.size(100.dp).background(color = Color.Magenta))
    }
}