C＃将图像裁剪为边缘模糊的椭圆

Question

我正在尝试将矩形图像裁剪为椭圆形，边缘模糊，如下所示：

resulting image has transparent edges (blended)

任何人都可以帮忙 此代码有效，但不提供边缘的透明度：

Image dstImage = new Bitmap(srcImage.Width, srcImage.Height, srcImage.PixelFormat);
Graphics g = Graphics.FromImage(dstImage);
using (Brush br = new SolidBrush(backGround))
{
    g.FillRectangle(br, 0, 0, dstImage.Width, dstImage.Height);
}
GraphicsPath path = new GraphicsPath();

path.AddEllipse(30, 30, dstImage.Width-60, dstImage.Height-60);
g.SetClip(path);
g.DrawImage(srcImage, 0, 0);