private void SetFocusPosition <T>(PointList <T> coll, T value, double focuspos) where T : Point, IComparable <T>
{
if (coll == null || value == null)
{
throw new ArgumentNullException("coll or value");
}
if (!ColorGradient.isValid(focuspos))
{
throw new ArgumentException("focuspos");
}
//
T[] sorted = coll.SortedArray();
int i = Array.IndexOf <T>(sorted, value);
if (i > 0)
{
//calculate focus
double w = sorted[i].Position - sorted[i - 1].Position;
if (w <= 0)
{
value.Focus = .5;
}
else
{
value.Focus = Math.Max(.0, Math.Min(1.0,
(focuspos - sorted[i - 1].Position) / w));
}
}
}
/// <summary>
/// ctor
/// </summary>
public AlphaPoint(double alpha, double focus, double point)
: base(point, focus)
{
if (!ColorGradient.isValid(alpha))
{
throw new ArgumentException("alpha");
}
_alpha = alpha;
}
/// <summary>
/// ctor
/// </summary>
public Point(double position, double focus)
{
if (!ColorGradient.isValid(position) ||
!ColorGradient.isValid(focus))
{
throw new ArgumentException("position or focus");
}
_position = position;
_focus = focus;
}
