Flips or rotates an Image.

ImageFragment.kt

private fun rotateImage(img: Bitmap, degree: Float): Bitmap {
    val matrix = Matrix()
    matrix.postRotate(degree)
    return Bitmap.createBitmap(img, 0, 0, img.width, img.height, matrix, true)
}

private fun flip(bitmap: Bitmap, horizontal: Boolean): Bitmap {
    val matrix = Matrix()
    matrix.preScale((if (horizontal) -1f else 1f), (if (!horizontal) -1f else 1f))
    return Bitmap.createBitmap(bitmap, 0, 0, bitmap.width, bitmap.height, matrix, true)
}