how to merge with Transparent image

[pawaom]

how to merge with Transparent image

When we us this code with normal image it works fine

**
* Uses the detected segmentation mask to overlay the background image
*/
fun generateMaskBgImage(image: Bitmap, bg: Bitmap): Bitmap {
val bgBitmap = Bitmap.createBitmap(image.width, image.height, image.config)

    for (y in 0 until maskHeight) {
        for (x in 0 until maskWidth) {
            val bgConfidence = ((1.0 - maskBuffer.float) * 255).toInt()
            var bgPixel = bg.getPixel(x, y)
            bgPixel = ColorUtils.setAlphaComponent(bgPixel, bgConfidence)
            bgBitmap.setPixel(x, y, bgPixel)
        }
    }
    maskBuffer.rewind()
    return mergeBitmaps(image, bgBitmap)
}

}

however when we try to merge it with transparent image it creates a black background instead of transparent background how can we merge and keep background transparent.