`SpinnerView` Calling `AdvanceAnimation` in Constructor

[tig]

Discussed in https://github.com/gui-cs/Terminal.Gui/discussions/3731

^{Originally posted by dasien September 5, 2024} Hello,

As part of my migration from v1 -> v2, i replaced my custom 'spinner' control with a SpinnerView. My implementation is as follows

   private readonly string[] _spinFrames = [
            "01100010", "01101001", "01110100", "01110111", "01100001", "01110010", "01100100", "01100101",
            "01101110"
        ];
            _spnAnimation = new SpinnerView()
            {
                X = 3, Y = 2, Width = 10, Height = 1, CanFocus = false, Visible = true,
                AutoSpin = true, SpinDelay = 80, Sequence = _spinFrames, Data = "spnAnimation"
            };

What i have noticed is that the first animation frame that appears is the default SpinnerStyle for the control, which is SpinnerStyle.Line. After that first frame, i see my sequence of characters. When i looked at the constructor for the SpinnerView i see that it is calling AdvanceAnimation() and that is setting an index of 1, which is getting the "\" character from the SpinnerStyle (the 2nd element in the list). I have two questions.

1. Can we remove the call to AdvanceAnimation() from the constructor? (I am happy to do it) I don't see the purpose for doing it there, but i could be missing something.

2. It seems like this code, given the default values for _bounceReverse and SpinReverse, will start with the [1] element in the array, skipping the [0] element the first time through.

 var d = 1;

                if ((_bounceReverse && !SpinReverse) || (!_bounceReverse && SpinReverse))
                {
                    d = -1;
                }

                _currentIdx += d;