public double AngleTo(Vector other)
{
var dotProduct = DotProduct(other);
var crossProduct = CrossProduct(other);
var angle = Math.Acos(
dotProduct / (Length * other.Length)
).ToDegrees();
var otherWay = crossProduct < 0;
return otherWay ? (360 - angle) : angle;
}
private double SliderAngle(PointerRoutedEventArgs e)
{
var centre = new Point(
ActualWidth / 2, ActualHeight / 2
);
var thumb = e.GetCurrentPoint(this)
.Position.RelativeTo(centre);
var vertical = new Vector(0, -1);
return thumb.AngleTo(vertical);
}
private double HalfAngle(Size size, double radius)
{
var thickness = (double)GetValue(Halo.ThicknessProperty);
var width = new Vector(
Math.Cos(Offset.ToRadians()) * size.Width,
Math.Sin(Offset.ToRadians()) * size.Height
).Length;
var height = new Vector(
Math.Sin(Offset.ToRadians()) * size.Width,
Math.Cos(Offset.ToRadians()) * size.Height
).Length;
return Math.Atan2(
width/2, radius - thickness/2 - height/2
).ToDegrees();
}
public double DotProduct(Vector other)
{
return (X * other.X) + (Y * other.Y);
}
public double CrossProduct(Vector other)
{
return (Y * other.X) - (X * other.Y);
}