An Android SeekBar, that's flipped horizontally

ReverseSeekBar.kt

class ReverseSeekBar : SeekBar {
    
    constructor(context: Context) : super(context) {
        init()
    }
    constructor(context: Context, attrs: AttributeSet?) : super(context, attrs) {
        init()
    }
    constructor(context: Context, attrs: AttributeSet?, defStyle: Int) : super(context, attrs, defStyle) {
        init()
    }

    private var first = true

    override fun onTouchEvent(event: MotionEvent): Boolean {
        event.setLocation(this.width - event.x, event.y)
        return super.onTouchEvent(event)
    }

    override fun getProgress(): Int {
        return max - super.getProgress() + min
    }

    override fun setProgress(progress: Int) {
        super.setProgress(max - progress + min)
    }

    override fun onDraw(canvas: Canvas?) {
        if (first) {
            first = false
            val old = progress
            progress = min + max - progress
            super.onDraw(canvas)
            progress = old
        } else
            super.onDraw(canvas)
    }

    private fun init() {
        rotation = 180f
    }

}

/*
<ReverseSeekBar
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:min="-50"
        android:max="50"
        android:progress="50"/>
*/