Drawing Bezier Splines Using GDI+

A Bézier spline is a curve specified by four points: two end points (p1 and p2) and two control points (c1 and c2). The curve begins at p1 and ends at p2. The curve does not pass through the control points, but the control points act as magnets, pulling the curve in certain directions and influencing the way the curve bends.

The following illustration shows a Bézier curve along with its endpoints and control points.

Drawing Bezier Splines

To draw a bezier spline, call the DrawBezier method of the Graphics object. The Pen is passed as one of the arguments to the DrawBezier method. The remaining arguments passed to the DrawBezier method are the endpoints and the control points.

The following is the syntax of DrawBezier method:

The following code example demonstrates how to draw a bezier spline with starting point (0, 0), control points (40, 20) and (80, 150), and ending point (100, 10):

Dim myImage As New Bitmap(300, 300, Imaging.PixelFormat.Format32bppRgb) Dim myGraphics As Graphics = Graphics.FromImage(myImage) myGraphics.Clear(Color.White) Dim myPen As New Pen(Color.Blue, 2) 'draw a bezier spline myGraphics.DrawBezier(myPen, 0, 0, 40, 20, 80, 150, 100, 10) myImage.Save(Response.OutputStream, Imaging.ImageFormat.Jpeg)