GDI+ 如何将图片绘制成圆形的图片

private Image CutEllipse(Image img, Rectangle rec, Size size)
{
Bitmap bitmap = new Bitmap(size.Width, size.Height);
using (Graphics g = Graphics.FromImage(bitmap))
{
using (TextureBrush br = new TextureBrush(img,System.Drawing.Drawing2D.WrapMode.Clamp, rec))
{
br.ScaleTransform(bitmap.Width / (float)rec.Width, bitmap.Height / (float)rec.Height);
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
g.FillEllipse(br, new Rectangle(Point.Empty, size));
}
}
return bitmap;
}

Image image = this.pictureBox1.Image;
Image newImage = CutEllipse(image, new Rectangle(0, 0, 150, 150), new Size(150, 150));
this.pictureBox2.Image = newImage;

<Grid>
<Ellipse Height="150" Width="150">
<Ellipse.Fill>
<ImageBrush ImageSource="Image/1_guwei4037.jpg" ></ImageBrush>
</Ellipse.Fill>
</Ellipse>
</Grid>