이미지뷰(ImageView)에 구멍뚫기

이미지뷰(ImageView)에 구멍뚫기

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val background = BitmapFactory.decodeResource(resources, R.drawable.cat)
        var foreground = BitmapFactory.decodeResource(resources, R.drawable.yellow)


        foreground = punchAHoleInABitmap(foreground)
        imageView.setImageBitmap(combineTwoBitmaps(background, foreground))
    }




    private fun punchAHoleInABitmap(foreground: Bitmap): Bitmap {

        val bitmap = Bitmap.createBitmap(foreground.width, foreground.height, Bitmap.Config.ARGB_8888)
        val canvas = Canvas(bitmap)
        val paint = Paint()

        canvas.drawBitmap(foreground, 0f, 0f, paint)
        paint.isAntiAlias = true
        paint.xfermode = PorterDuffXfermode(PorterDuff.Mode.CLEAR)

        val radius = 600f
        Log.d("SSS", "screensize:${getScreenSize()} width:${imageView.measuredWidth}")
        val x = getScreenSize().x-100f;
        val y = 100f;
        canvas.drawCircle(x, y, radius, paint)
        return bitmap
    }



    private fun combineTwoBitmaps(background: Bitmap, foreground: Bitmap): Bitmap {
        val combinedBitmap = Bitmap.createBitmap(background.width, background.height, background.config)
        val canvas = Canvas(combinedBitmap)
        val paint = Paint(Paint.FILTER_BITMAP_FLAG)
        canvas.drawBitmap(background, 0f, 0f, paint)
        canvas.drawBitmap(foreground, 0f, 0f, paint)
        return combinedBitmap
    }



    private fun getScreenSize(): Point {
        val window = getSystemService(WINDOW_SERVICE) as WindowManager
        val display = window.defaultDisplay
        val size = Point()

        display.getSize(size)
        return size
    }


}

val background = BitmapFactory.decodeResource(resources, R.drawable.cat)
var foreground = BitmapFactory.decodeResource(resources, R.drawable.yellow)

불러오는 이미지는 bmp이어야 한다.

아니면 drawable을 bmp로 바꾸는 작업을 해줘야 한다.

참고: https://www.techrepublic.com/article/punch-a-hole-in-a-bitmap-by-using-androids-porter-duff-xfer/