LottieAnimation.kt

import androidx.compose.foundation.Canvas
import androidx.compose.runtime.Composable
import androidx.compose.runtime.LaunchedEffect
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.setValue
import androidx.compose.runtime.withFrameNanos
import androidx.compose.ui.Modifier
import androidx.compose.ui.geometry.Offset
import androidx.compose.ui.graphics.drawscope.drawIntoCanvas
import androidx.compose.ui.graphics.drawscope.withTransform
import androidx.compose.ui.graphics.nativeCanvas
import org.jetbrains.skia.skottie.Animation

@Composable
fun LottieAnimation(
  animation: Animation,
  modifier: Modifier = Modifier,
  loop: Boolean = true,
  scale: Float = 1f,
) {
  var frameTimeInSeconds by remember(animation) { mutableStateOf(0f) }

  Canvas(modifier) {
    withTransform({ scale(scale, scale, Offset.Zero) }) {
      drawIntoCanvas {
        animation.seekFrameTime(frameTimeInSeconds).render(it.nativeCanvas)
      }
    }
  }

  LaunchedEffect(animation) {
    var lastFrameNanos = Long.MIN_VALUE

    while (true) {
      val animationEnded = withFrameNanos {
        if (lastFrameNanos == Long.MIN_VALUE) lastFrameNanos = it

        val nextFrameTimeInSeconds = (it - lastFrameNanos).toFloat() / 1_000_000_000L

        frameTimeInSeconds = if (nextFrameTimeInSeconds >= animation.duration) {
          lastFrameNanos = Long.MIN_VALUE
          animation.duration
        } else nextFrameTimeInSeconds

        return@withFrameNanos frameTimeInSeconds == animation.duration && !loop
      }

      if (animationEnded) break
    }
  }
}