vb图像问题

Dim bmp As New Bitmap(1000, 700)  
Dim g As Graphics = Graphics.FromImage(bmp)  
Dim pen As Pen = New Pen(Color.Black)  
Dim outline As Rectangle = New Rectangle(200, 50, 350, 350)  
g.FillPie(New SolidBrush(Color.Red), outline, 0, s1)          
g.FillPie(New SolidBrush(Color.Yellow), outline, s1, s2)    
g.FillPie(New SolidBrush(Color.Blue), outline, s1 + s2, s3)  

bitmap是画布的大小 （x,y,width,height）x,y画笔起点 width和height是矩形的属性