RecordButton_2.kt

private var cx: Float = 0f // x coordinate of the center
private var cy: Float = 0f // y coordinate of the center
private var radius: Float = 0f // the radius of the view = min(width, height) * 0.95

override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec)
    if (measuredHeight > 0 && measuredWidth > 0) {
        cx = measuredWidth / 2f
        cy = measuredHeight / 2f
        radius = Math.min(measuredHeight, measuredWidth) / 2 * 0.95f - paddingBottom
    }
}