PinchedEventArgs.cs

namespace Gondwana.Input.Touch.Gestures;

public sealed class PinchedEventArgs : EventArgs
{
    public PinchPhase Phase { get; }

    public IReadOnlyList<int> TouchIds { get; }

    public System.Drawing.PointF Center { get; }

    public double StartingDistance { get; }

    public double PreviousDistance { get; }

    public double ScaleDelta { get; }

    public double CurrentDistance { get; }

    public double TotalScale { get; }

    public PinchedEventArgs(double scaleDelta, double currentDistance)
    {
        Phase = PinchPhase.Updated;
        TouchIds = Array.Empty<int>();
        Center = System.Drawing.PointF.Empty;
        StartingDistance = currentDistance;
        PreviousDistance = scaleDelta != 0 ? currentDistance / scaleDelta : currentDistance;
        CurrentDistance = currentDistance;
        ScaleDelta = scaleDelta;
        TotalScale = scaleDelta;
    }

    public PinchedEventArgs(
        PinchPhase phase,
        IReadOnlyList<int> touchIds,
        System.Drawing.PointF center,
        double startingDistance,
        double previousDistance,
        double currentDistance)
    {
        Phase = phase;
        TouchIds = touchIds ?? throw new ArgumentNullException(nameof(touchIds));
        Center = center;
        StartingDistance = startingDistance;
        PreviousDistance = previousDistance;
        CurrentDistance = currentDistance;
        ScaleDelta = previousDistance > 0 ? currentDistance / previousDistance : 1.0;
        TotalScale = startingDistance > 0 ? currentDistance / startingDistance : 1.0;
    }
}