class CircleCropTransformation : Transformation {
    override fun transform(source: Bitmap?): Bitmap {
        val size: Int = Math.min(source!!.width, source.height)
        val x: Int = (source.width - size) / 2
        val y: Int = (source.height - size) / 2

        val squaredBitmap: Bitmap = Bitmap.createBitmap(source, x, y, size, size)
        if (squaredBitmap != source) {
            source.recycle()
        }

        val bitmap: Bitmap = Bitmap.createBitmap(size, size, source.config)
        val canvas = Canvas(bitmap)
        val paint = Paint()

        val shader = BitmapShader(
            squaredBitmap,
            Shader.TileMode.CLAMP,
            Shader.TileMode.CLAMP
        )

        paint.shader = shader
        paint.isAntiAlias = true

        val r = size / 2f
        canvas.drawCircle(r, r, r, paint)
        squaredBitmap.recycle()
        return bitmap

    }

    override fun key(): String {
        return "circle"
    }
}