/// <summary>
/// Draws a cubic Beziér spline defined by start, end and two control points.
/// </summary>
/// <param name="bmp">The WriteableBitmap.</param>
/// <param name="x1">The x-coordinate of the start point.</param>
/// <param name="y1">The y-coordinate of the start point.</param>
/// <param name="cx1">The x-coordinate of the 1st control point.</param>
/// <param name="cy1">The y-coordinate of the 1st control point.</param>
/// <param name="cx2">The x-coordinate of the 2nd control point.</param>
/// <param name="cy2">The y-coordinate of the 2nd control point.</param>
/// <param name="x2">The x-coordinate of the end point.</param>
/// <param name="y2">The y-coordinate of the end point.</param>
/// <param name="color">The color.</param>
public static void DrawBezier(this WriteableBitmap bmp, int x1, int y1, int cx1, int cy1, int cx2, int cy2,
int x2, int y2, 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.DrawBezier(x1, y1, cx1, cy1, cx2, cy2, x2, y2, col);
}
/// <summary>
/// Draws a series of cubic Beziér splines each defined by start, end and two control points.
/// The ending point of the previous curve is used as starting point for the next.
/// Therfore the inital curve needs four points and the subsequent 3 (2 control and 1 end point).
/// </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, cx1, cy1, cx2, cy2, x2, y2, cx3, cx4 ..., xn, yn).</param>
/// <param name="color">The color for the spline.</param>
public static void DrawBeziers(this WriteableBitmap bmp, int[] points, int color)
{
int x1 = points[0];
int y1 = points[1];
int x2, y2;
for (int i = 2; i + 5 < points.Length; i += 6)
{
x2 = points[i + 4];
y2 = points[i + 5];
bmp.DrawBezier(x1, y1, points[i], points[i + 1], points[i + 2], points[i + 3], x2, y2, color);
x1 = x2;
y1 = y2;
}
}
/// <summary>
/// Draws a cubic Beziér spline defined by start, end and two control points.
/// </summary>
/// <param name="bmp">The WriteableBitmap.</param>
/// <param name="x1">The x-coordinate of the start point.</param>
/// <param name="y1">The y-coordinate of the start point.</param>
/// <param name="cx1">The x-coordinate of the 1st control point.</param>
/// <param name="cy1">The y-coordinate of the 1st control point.</param>
/// <param name="cx2">The x-coordinate of the 2nd control point.</param>
/// <param name="cy2">The y-coordinate of the 2nd control point.</param>
/// <param name="x2">The x-coordinate of the end point.</param>
/// <param name="y2">The y-coordinate of the end point.</param>
/// <param name="color">The color.</param>
public static void DrawBezier(this WriteableBitmap bmp, int x1, int y1, int cx1, int cy1, int cx2, int cy2, int x2, int y2, Color color)
{
var col = ConvertColor(color);
bmp.DrawBezier(x1, y1, cx1, cy1, cx2, cy2, x2, y2, col);
}