VB+三次样条曲线+绘制示例

在Visual Basic（VB）中，利用Bezier曲线可以绘制出多种图形。例如，通过设置控制点的位置和数量，可以实现对椭圆的精确绘制。 以下是一个使用Bezier曲线绘制椭圆的代码示例： ```vb Dim x As Single, y As Single Dim cx As Single, cy As Single Dim rx As Single, ry As Single Dim numControlPoints As Integer = 8 '控制点数量，奇数 Dim controlPoints(1 To numControlPoints) As PointF ' 设置椭圆的圆心和半径 cx = x cy = y rx = 100: ry = 50 ' 计算控制点的坐标 For i = 1 To numControlPoints - 2 Step 2 Dim angle As Single, radian As Single angle = (i * 360) / numControlPoints radian = angle * Math.PI / 180.0 x = cx + rx * Cos(radian) '控制点横坐标 y = cy - ry * Sin(radian) '控制点纵坐标 controlPoints(i).X = x controlPoints(i).Y = y Next i ' 绘制椭圆 Graphics g = Graphics.FromImage(bmp) '创建绘图对象 g.FillEllipse(Brushes.White, cx - rx, cy - ry, rx * 2.0, ry * 2.0) '填充椭圆区域为白色 For i = 1 To numControlPoints Step 2 Dim cp1 As PointF = controlPoints(i + 1), cp2 As PointF = controlPoints(i) cp1.X *= -1: cp1.Y *= -1 cp2.X *= -1: cp2.Y *= -1 g.DrawBezier(Pens.Black, cp1, cp2) '绘制曲线 Next i