在图像上的各个坐标上画一个圆

Question

如何在给定坐标的图像上绘制圆。例如，我有一个700x400的图像，想在以（320,200）点为中心的图像上画一个圆。

Answer 1

private void DrawGraphics()
    {
        if (!this.DoubleBuffered)
        {
            //get rid of flickering while drawing images
            this.DoubleBuffered = true;
        }



        //make sure you have write to the location you plan to save too 
        var imagePath = @"MyStuff\Image.png";

        //Image bmp = new Bitmap(700,400);// you can use an empty image

        Image bmp =new Bitmap(new Bitmap(@"MyStuff\img1.jpg"), new Size(700,400));
        Graphics gg = Graphics.FromImage(bmp);

        float Diameter = 100f;
        Point givenPoint = new Point(320, 200);
        gg.DrawEllipse(Pens.Blue, givenPoint.X - (Diameter / 2), givenPoint.Y - (Diameter / 2), Diameter , Diameter );



        //save the new image
        bmp.Save(imagePath);
        this.BackgroundImage = bmp;
        gg.Dispose();
    }