alpha

Functions summary

Modifier

Draw content with modified alpha that may be less than 1.
Cmn

Functions

Modifier.alpha

Cmn 
fun Modifier.alpha(alpha: Float): Modifier

Draw content with modified alpha that may be less than 1.

Usage of this API renders this composable into a separate graphics layer. Note when an alpha less than 1.0f is provided, contents are implicitly clipped to their bounds. This is because an intermediate compositing layer is created to render contents into first before being drawn into the destination with the desired alpha. This layer is sized to the bounds of the composable this modifier is configured on, and contents outside of these bounds are omitted.

Performance Note: For animating alpha, it is highly recommended to use Modifier.graphicsLayer instead (e.g., Modifier.graphicsLayer { alpha = ... }). Changing the alpha parameter on Modifier.alpha causes the composable to be recomposed, which is less efficient than updating the alpha property within graphicsLayer, as graphicsLayer can optimize this change without requiring recomposition.

import androidx.compose.foundation.background
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.size
import androidx.compose.ui.Modifier
import androidx.compose.ui.draw.alpha
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.unit.dp

Box(Modifier.size(100.dp).alpha(alpha = 0.5f).background(Color.Red))
Parameters
alpha: Float

the fraction of children's alpha value and must be between 0 and 1, inclusive.
See also
graphicsLayer

Example usage: