如何使用 GDI+ 绘制椭圆和圆。

要绘制椭圆，您需要指定外部矩形。 GDI+ 负责其余的工作。 DrawEllipse 绘制一个由一对坐标、一个高度和一个宽度指定的矩形定义的椭圆（高度和宽度相等的椭圆是一个圆）。

要绘制椭圆，应用程序创建一支笔和四个坐标（或者一个矩形），然后调用 DrawEllipse。

Private Sub Form1_Paint(ByVal sender As System.Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles MyBase.Paint
	' Create Pens
	Dim redPen As New Pen(Color.Red, 6)
	Dim bluePen As New Pen(Color.Blue, 4)
	Dim greenPen As New Pen(Color.Green, 2)
	' Create a rectangle
	Dim rect As New Rectangle(80, 80, 50, 50)
	' Draw ellipses
	e.Graphics.DrawEllipse(greenPen, 100.0F, 100.0F, 10.0F, 10.0F)
	e.Graphics.DrawEllipse(redPen, rect)
	e.Graphics.DrawEllipse(bluePen, 60, 60, 90, 90)
	e.Graphics.DrawEllipse(greenPen, 40.0F, 40.0F, 130.0F, 130.0F)
	'Dispose of objects
	redPen.Dispose()
	greenPen.Dispose()
	bluePen.Dispose()
End Sub