Question

I need to solve a problem by rotating an image, but I have this code to rotate the image does not rotate completely

public static Image RotateImage(Image img, float rotationAngle)
        {
            //create an empty Bitmap image
            Bitmap bmp = new Bitmap(img.Width, img.Height);

            //turn the Bitmap into a Graphics object
            Graphics gfx = Graphics.FromImage(bmp);

            //now we set the rotation point to the center of our image
            gfx.TranslateTransform((float)bmp.Width / 2, (float)bmp.Height / 2);

            //now rotate the image
            gfx.RotateTransform(rotationAngle);

            gfx.TranslateTransform(-(float)bmp.Width / 2, -(float)bmp.Height / 2);

            //set the InterpolationMode to HighQualityBicubic so to ensure a high
            //quality image once it is transformed to the specified size
            gfx.InterpolationMode = InterpolationMode.HighQualityBicubic;

            //now draw our new image onto the graphics object
            gfx.DrawImage(img, new System.Drawing.Point(0, 0));

            //dispose of our Graphics object
            gfx.Dispose();

            //return the image
            return bmp;
        }

And use this to call method. The right is rotate the image rectangle that contains, and to avoid cutting the image

Bitmap bitmap = (Bitmap)Pix.Image;
Pix.Image = (Bitmap)(RotateImage(bitmap, 20.0f));

Answer 1

private Bitmap RotateImageByAngle(Image oldBitmap, float angle)
{
    var newBitmap = new Bitmap(oldBitmap.Width, oldBitmap.Height);
    newBitmap.SetResolution(oldBitmap.HorizontalResolution, oldBitmap.VerticalResolution);
    var graphics = Graphics.FromImage(newBitmap);
    graphics.TranslateTransform((float)oldBitmap.Width / 2, (float)oldBitmap.Height / 2);
    graphics.RotateTransform(angle);
    graphics.TranslateTransform(-(float)oldBitmap.Width / 2, -(float)oldBitmap.Height / 2);
    graphics.DrawImage(oldBitmap, new Point(0, 0));
    return newBitmap;
}