val mImageView = findViewById<ImageView>(R.id.image_view_1)
val mButton = findViewById<Button>(R.id.button_1)
val tv1 = findViewById<View>(R.id.textView)
val tv2 = findViewById<View>(R.id.textView2)
val currentDisplay = windowManager.currentWindowMetrics
val dw = currentDisplay.bounds.width()
val dh = currentDisplay.bounds.height()
val mBitmap = Bitmap.createBitmap(dw, dh, Bitmap.Config.ARGB_8888)
val mCanvas = Canvas(mBitmap)
mImageView.setImageBitmap(mBitmap)
mButton.setOnClickListener {
    val mPaint = Paint()
    mPaint.color = Color.GREEN
    mPaint.style = Paint.Style.STROKE
    mPaint.strokeWidth = 10F
    mPaint.isAntiAlias = true
    val mStartX = tv1.bottom.toFloat()
    val mStartY = tv1.left.toFloat()
    val mStopX = tv2.top.toFloat()
    val mStopY = tv2.right.toFloat()
    mCanvas.drawLine(mStartX, mStartY, mStopX, mStopY, mPaint)
    mImageView.setImageBitmap(mBitmap)
}