/// <summary>
/// Draws a closed Cardinal spline (cubic) defined by a point collection.
/// The cardinal spline passes through each point in the collection.
/// </summary>
/// <param name="bmp">The WriteableBitmap.</param>
/// <param name="points">The points for the curve in x and y pairs, therefore the array is interpreted as (x1, y1, x2, y2, x3, y3, x4, y4, x1, x2 ..., xn, yn).</param>
/// <param name="tension">The tension of the curve defines the shape. Usually between 0 and 1. 0 would be a straight line.</param>
/// <param name="color">The color for the spline.</param>
public static void DrawCurveClosed(this WriteableBitmap bmp, int[] points, float tension, Color color)
{
// Add one to use mul and cheap bit shift for multiplicaltion
int a = color.A + 1;
int col = (color.A << 24)
| ((byte)((color.R * a) >> 8) << 16)
| ((byte)((color.G * a) >> 8) << 8)
| ((byte)((color.B * a) >> 8));
bmp.DrawCurveClosed(points, tension, col);
}
/// <summary>
/// Draws a closed Cardinal spline (cubic) defined by a point collection.
/// The cardinal spline passes through each point in the collection.
/// </summary>
/// <param name="bmp">The WriteableBitmap.</param>
/// <param name="points">The points for the curve in x and y pairs, therefore the array is interpreted as (x1, y1, x2, y2, x3, y3, x4, y4, x1, x2 ..., xn, yn).</param>
/// <param name="tension">The tension of the curve defines the shape. Usually between 0 and 1. 0 would be a straight line.</param>
/// <param name="color">The color for the spline.</param>
public static void DrawCurveClosed(this WriteableBitmap bmp, int[] points, float tension, Color color)
{
var col = ConvertColor(color);
bmp.DrawCurveClosed(points, tension, col);
}
