c# – Rotate image around center itself

Question:

I'm developing a C# application and would like to know how to freely rotate a bitmap that is drawn in a pictureBox without rotating the entire _pictureBox_e so that the bitmap rotates around its own center . Here's my last attempt:

Bitmap irisref1;

private void pcbREFOLHOS_Paint(object sender, PaintEventArgs e)
{
    e.Graphics.TranslateTransform(pcbREFOLHOS.Width / 2, pcbREFOLHOS.Height / 2);
    e.Graphics.RotateTransform(contador);
    e.Graphics.DrawImage(irisref1, new PointF((5 - atualdata1 - 2.5f) * 10, 0));
    contador++;
    //e.Graphics.DrawEllipse(new Pen(Color.White, 3), 0, 0, 150, 60);
}

This way I don't get the expected result, as the image "orbits" around the specified point, but I would like the image to rotate around its own center. Can anyone help with this problem?

Answer:

Try implementing the following method:

public static Bitmap RotateImageN(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.
    Graphics g = Graphics.FromImage(returnBitmap);
    //move rotation point to center of image.
    g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
    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);
    g.DrawImage(b, 0,0,b.Width, b.Height);
    return returnBitmap;
}

Then you just need to provide the Bitmap and the angle you want to rotate the image, then getting the result.

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