public void ResizeImageWithConstraints(ref ps.Document doc, double width, double height) { if (doc.Width/doc.Height<=width/height) { doc.ResizeImage(Height: height, ResampleMethod: ps.PsPDFResampleType.psPDFBicubic); } else { doc.ResizeImage(Width: width, ResampleMethod: ps.PsPDFResampleType.psPDFBicubic); } }