Issue with keeping image centered while zooming

Leadtools v.17.5 .Net libraries

Hello,

As the subject says I am having an issue keeping my image centered while zooming in or out.
When I zoom in, the viewing area is being "pushed" up until the viewing area reaches the top of the image.
When I zoom out, the viewing area is being "pushed" down until the viewing area reaches the bottom of the image.

The following code is what I am using to handle the zoom event.  It is based upon the example for the RasterImageViewer.CenterAtPoint() function.

        private void Zoom(bool isPositive)
        {
            double temp = Math.Round(m_viewer.ScaleFactor, 2);
            Rectangle rc = Rectangle.Intersect(m_viewer.PhysicalViewRectangle, m_viewer.ClientRectangle);

            PointF center = new PointF((float)((rc.Left + rc.Width / 2)), (float)((rc.Top + rc.Height / 2)));
            Leadtools.Drawing.Transformer t = new Leadtools.Drawing.Transformer(m_viewer.Transform);
            center = t.PointToLogical(center);

            if (isPositive)
                m_viewer.ScaleFactor = temp + 0.01;
            else
            {
                if (temp - 0.01 > 0.05)
                {
                    if (temp > 0.75)
                        m_viewer.ScaleFactor = temp - 0.5; 
                    else
                        m_viewer.ScaleFactor = temp - 0.01;
                }
                else
                    m_viewer.ScaleFactor = 0.05;
            }

            // Get the center of what you saw before the zoom in physical coordinates
            t = new Leadtools.Drawing.Transformer(m_viewer.Transform);
            center = t.PointToPhysical(center);

            m_viewer.CenterAtPoint(Point.Round(center));
            m_model.Magnification = (float)m_viewer.ScaleFactor;
        }

The image stays centered until it is to big to fit in the viewing area, at which point the image begins to creep up when zooming.
Any ideas would be greatly appreciated.

Thanks

Tony

Tony,
The difference might be caused by the scrollbars if they are enabled.
See code project posted by Adnan Ismail in forum post:
http://support.leadtools.com/cs/forums/16679/ShowPost.aspx#16679

Thank you Ibrahim, that worked.

Tony