Filling Open Figures

You can fill a path by passing a GraphicsPath object to the Graphics.FillPath method. The FillPath method fills the path according to the fill mode (alternate or winding) currently set for the path. If the path has any open figures, the path is filled as if those figures were closed. GDI+ closes a figure by drawing a straight line from its ending point to its starting point.

The following example creates a path that has one open figure (an arc) and one closed figure (an ellipse). The Graphics.FillPath method fills the path according to the default fill mode, which is FillMode.Alternate.

Dim path As New GraphicsPath()

' Add an open figure.
path.AddArc(0, 0, 150, 120, 30, 120)

' Add an intrinsically closed figure.
path.AddEllipse(50, 50, 50, 100)

Dim pen As New Pen(Color.FromArgb(128, 0, 0, 255), 5)
Dim brush As New SolidBrush(Color.Red)

' The fill mode is FillMode.Alternate by default.
e.Graphics.FillPath(brush, path)
e.Graphics.DrawPath(pen, path)
[C#]
GraphicsPath path = new GraphicsPath();

// Add an open figure.
path.AddArc(0, 0, 150, 120, 30, 120);

// Add an intrinsically closed figure.
path.AddEllipse(50, 50, 50, 100);

Pen pen = new Pen(Color.FromArgb(128, 0, 0, 255), 5);
SolidBrush brush = new SolidBrush(Color.Red);

// The fill mode is FillMode.Alternate by default.
e.Graphics.FillPath(brush, path);
e.Graphics.DrawPath(pen, path);

The following illustration shows the output of the preceding code. Note that the path is filled (according to FillMode.Alternate) as if the open figure were closed by a straight line from its ending point to its starting point.