c# - Rotating graphics?

Question

I have this code, that draws an image.

private void timer1_Tick(object sender, EventArgs e)
{
    Invalidate();
}

protected override void OnPaint(PaintEventArgs e)
{
    var tempRocket = new Bitmap(Properties.Resources.rocket);

    using (var g = Graphics.FromImage(tempRocket))
    {
        e.Graphics.DrawImage(tempRocket, 150, 150);
    }
}

Yet what do I do to rotate it?

Answer 1

public static Bitmap RotateImage(Bitmap b, float angle)
{
  //create a new empty bitmap to hold rotated image
  Bitmap returnBitmap = new Bitmap(b.Width, b.Height);
  //make a graphics object from the empty bitmap
  using(Graphics g = Graphics.FromImage(returnBitmap)) 
  {
      //move rotation point to center of image
      g.TranslateTransform((float)b.Width / 2, (float)b.Height / 2);
      //rotate
      g.RotateTransform(angle);
      //move image back
      g.TranslateTransform(-(float)b.Width / 2, -(float)b.Height / 2);
      //draw passed in image onto graphics object
      g.DrawImage(b, new Point(0, 0)); 
  }
  return returnBitmap;
}