NotchEdgeTreatment.kt

package com.traveller

import com.google.android.material.shape.EdgeTreatment
import com.google.android.material.shape.ShapePath

class NotchEdgeTreatment(private val notchRadius: Float) : EdgeTreatment() {
    override fun getEdgePath(
        length: Float,
        center: Float,
        interpolation: Float,
        shapePath: ShapePath
    ) {
        shapePath.lineTo(center, 0f)
        shapePath.addArc(
            center - notchRadius,
            -notchRadius,
            center + notchRadius,
            notchRadius,
            180f,
            -180f
        )
        shapePath.lineTo(length, 0f)
    }
}