android 挖空效果，从PopupWindow中引导图挖空

自定义AreaMaskView

class AreaMaskView @JvmOverloads constructor(
    context: Context, attrs: AttributeSet? = null
): View(context, attrs) {

    /**
     * 目标布局周围的空白区域
     */
    private val brimRect = RectF()

    /**
     * 显示目标区域的画笔
     */
    private val brimPaint = Paint()

    /**
     * 圆角
     */
    private var mRadius = dpToPx(8f)
    /**
     * 蒙版的背景颜色
     */
    private val bgColor = Color.parseColor("#80222427")

    init {
        brimPaint.color = Color.TRANSPARENT
        brimPaint.maskFilter = BlurMaskFilter(10f,BlurMaskFilter.Blur.INNER)
        //图像合成模式为CLEA
        brimPaint.xfermode = PorterDuffXfermode(PorterDuff.Mode.CLEAR)
        setLayerType(LAYER_TYPE_SOFTWARE, null)
    }

  fun setTargetRect(targetRect:Rect){
      brimRect.left = targetRect.left.toFloat()
      brimRect.right = targetRect.right.toFloat()
      val top = targetRect.top.toFloat()  - getStatusBarHeight()
      brimRect.top = top
      brimRect.bottom = targetRect.bottom.toFloat()  - getStatusBarHeight()
      invalidate()
  }
    override fun onDraw(canvas: Canvas?) {
        super.onDraw(canvas)
        canvas?.drawColor(bgColor)
        canvas?.drawRoundRect(brimRect, mRadius, mRadius, brimPaint)
        canvas?.save()
        canvas?.restore()
    }
}

XxxxPopupWindow弹框

class XxxxPopupWindow(
    val context: Context,
    val callback: ()->Unit
) :
    XxxxPopupWindow(context) {


/**
     * 当前蒙版的目标布局的坐标位置
     */
    private val targetRect = Rect()

    fun showAtLocation(anchor: View) {
        anchor.getGlobalVisibleRect(targetRect)
        mBinding.AreaMaskView(布局中的id).setTargetRect(targetRect)
}
}

<FrameLayout
            android:id="@+id/content"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        >
 <cn.dandroid.AreaMaskView
            android:id="@+id/dandroid_view"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            />
        <androidx.constraintlayout.widget.ConstraintLayout
            android:id="@+id/cl_tips_popup"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            >
</androidx.constraintlayout.widget.ConstraintLayout>
    </FrameLayout>