UI lag when converting bitmap to bytearray

[BoikoIlya]

This is IOS part of kmp project. My ui is lagging when I convert bitmap to bytearray

` val originalBitmap = imageBitmap.asSkiaBitmap()

val width: Int
val height: Int

when (aspectRatio) {
    "9:16" -> {
        height = 3840
        width = 2160
    }
    "1:1" -> {
        height = 3840
        width = 3840
    }
    else -> {
        width = originalBitmap.width
        height = originalBitmap.height
    }
}

val scaledBitmap = Bitmap().apply {
    allocN32Pixels(width, height)
}

val timeDraw = measureTime {
    val canvas = Canvas(scaledBitmap)
    val srcRect = Rect.makeWH(originalBitmap.width.toFloat(), originalBitmap.height.toFloat())
    val dstRect = Rect.makeWH(width.toFloat(), height.toFloat())
    canvas.drawImageRect(Image.makeFromBitmap(originalBitmap), srcRect, dstRect)
}.inWholeMilliseconds
println("Drawing bitmap took: $timeDraw ms")

val byteArray = withContext(Dispatchers.Default) {
    var result: ByteArray? = null
    val timeEncode = measureTime {
       result = Image.makeFromBitmap(scaledBitmap).encodeToData(EncodedImageFormat.PNG)?.bytes ?: ByteArray(1)
    }.inWholeMilliseconds
    println("Encoding image took: $timeEncode ms")
    result!!
}`

I launch it in coroutine on default dispatcher but it still lag my ui. I have investigated that problem cause that line:
Image.makeFromBitmap(scaledBitmap).encodeToData(EncodedImageFormat.PNG)?.bytes

I use PNG format and it leads to 2 sec ui delay, but with JPEG it works very fast with no delay. please help

[tonsky]

Do it in background thread?

[BoikoIlya]

I am doing that in background thread, in coroutine, default dispatcher