Override Picturbox OnPaint Event to Rotate the Image -Create Custom Picturebox

Question

I want to create a custom control or override the pictuebox's onpaint event such that i get access to the image before its drawn in the picturbox,so that i can rotate the image.

I know that i can do something like this

private void pictureBox1_Paint(object sender, PaintEventArgs e) {

    e.Graphics.DrawRectangle(Pens.Black, new Rectangle(10, 10, 20, 20));
}

How to get access to the image and how to create a custom control.

Answer 1

Here is a quick example of a subclass: It hides the original Image property and replaces it with one that does a rotation before assigning it:

class RotatedPictureBox : PictureBox
{

    private Image image;

    public new  Image Image {
        get { return image; }  // ?? you may want to undo the rotation here ??
        set {
              Bitmap bmp = value as Bitmap ;
              // use the rotation you need!
              if ( bmp != null )  bmp.RotateFlip(RotateFlipType.Rotate270FlipX);
              image = bmp;
              base.Image = Image;
            }
        }


    }
    public RotatedPictureBox ()
    {
    }
}

Caveat: Assigning an Image seems to work but I didn't test it for all possible uses.. Known limitations

• It doesn't rotate images assigned via ImageLocation.
• I had a crash once, when assigning an image in the Designer, but can't reproduce.