The final on draw I'm using

OnDraw.kt

override fun onDraw(canvas: Canvas) {
        super.onDraw(canvas)
        val path = Path()
        path.apply {
            moveTo(shadowSize + cornerRadius, shadowSize + cornerRadius)
            arcTo(0f, 0f, shadowSize * 2 + 2 * cornerRadius, shadowSize * 2 + 2 * cornerRadius, 180f, 90f, false)
            moveTo(shadowSize + cornerRadius, shadowSize + cornerRadius)
            arcTo(shadowSize, shadowSize, shadowSize + 2 * cornerRadius, shadowSize + 2 * cornerRadius, 270f, -90f, false)
        }
        canvas.drawPath(path, radialGradientPaint)
        canvas.drawRect(RectF(cornerRadius + shadowSize, 0f, width - cornerRadius - shadowSize, shadowSize), linearGradientPaint)
        canvas.save()
        canvas.rotate(180f, xCenter, yCenter)
        canvas.drawRect(RectF(cornerRadius + shadowSize, 0f, width - cornerRadius - shadowSize, shadowSize), linearGradientPaint)
        canvas.drawPath(path, radialGradientPaint)
        canvas.restore()
        canvas.save()
        canvas.rotate(90f, xCenter, yCenter)
        canvas.drawRect(RectF(cornerRadius + shadowSize, 0f, height - cornerRadius - shadowSize, shadowSize), linearGradientPaint)
        canvas.drawPath(path, radialGradientPaint)
        canvas.restore()
        canvas.rotate(270f, xCenter, yCenter)
        canvas.drawRect(RectF(cornerRadius + shadowSize, 0f, height - cornerRadius - shadowSize, shadowSize), linearGradientPaint)
        canvas.drawPath(path, radialGradientPaint)

    }