Masking bitmap with given destinationImage. Useful for masking ImageViews

BitmapExtension.kt

fun Bitmap.maskWith(destinationImage: Bitmap, mode: PorterDuff.Mode): Bitmap {
    val result = this.copy(Bitmap.Config.ARGB_8888, true)
    val canvas = Canvas(result)

    val paint = Paint()
    canvas.drawBitmap(destinationImage, 0f, 0f, paint)
    paint.xfermode = PorterDuffXfermode(mode)

    canvas.drawBitmap(this, 0f, 0f, paint)

    return result
}

Example.kt

val mask = BitmapFactory.decodeResource(resources, R.drawable.mask)
val image = BitmapFactory.decodeResource(resources, R.drawable.image)

val maskedBitmap = image.maskWith(mask, PorterDuff.Mode.DST_ATOP)
imageView.setImageBitmap(maskedBitmap)