Modifier extension for shimmer animation in compose

shimmer_modifier_compose.kt

import androidx.compose.animation.core.FastOutSlowInEasing
import androidx.compose.animation.core.RepeatMode
import androidx.compose.animation.core.animateFloat
import androidx.compose.animation.core.infiniteRepeatable
import androidx.compose.animation.core.rememberInfiniteTransition
import androidx.compose.animation.core.tween
import androidx.compose.foundation.background
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.setValue
import androidx.compose.ui.Modifier
import androidx.compose.ui.composed
import androidx.compose.ui.geometry.Offset
import androidx.compose.ui.graphics.Brush
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.layout.onGloballyPositioned
import androidx.compose.ui.unit.IntSize

fun Modifier.shimmer(toShow: Boolean): Modifier = composed {
    if (toShow) {
        val shimmerColors = listOf(
            Color.LightGray.copy(alpha = 0.6f),
            Color.LightGray.copy(alpha = 0.2f),
            Color.LightGray.copy(alpha = 0.6f),
        )

        var size by remember { mutableStateOf(IntSize.Zero) }

        val transition = rememberInfiniteTransition(label = "")
        val transitionAnimation = transition.animateFloat(
            initialValue = 0f,
            targetValue = 1000f,
            animationSpec = infiniteRepeatable(
                animation = tween(
                    durationMillis = 1000,
                    easing = FastOutSlowInEasing
                ),
                repeatMode = RepeatMode.Reverse
            ), label = ""
        )
        background(
            brush = Brush.linearGradient(
                colors = shimmerColors,
                start = Offset.Zero,
                end = Offset(x = transitionAnimation.value, y = transitionAnimation.value)
            )
        ).onGloballyPositioned { size = it.size }
    } else {
        Modifier
    }
}