หมุน PDF

string dataDir = RunExamples.GetDataDir_AsposePdf_Pages();
Document doc = new Document(dataDir + "input.pdf");
foreach (Page page in doc.Pages)
{
    Aspose.Pdf.Rectangle r = page.MediaBox;
    double newHeight = r.Width;
    double newWidth = r.Height;
    double newLLX = r.LLX;
    double newLLY = r.LLY + (r.Height - newHeight);
    page.MediaBox = new Aspose.Pdf.Rectangle(newLLX, newLLY, newLLX + newWidth, newLLY + newHeight);
    // Sometimes we also need to set CropBox (if it was set in original file)
    page.CropBox = new Aspose.Pdf.Rectangle(newLLX, newLLY, newLLX + newWidth, newLLY + newHeight);
    // Setting Rotation angle of page
    page.Rotate = Rotation.on90;
}
dataDir = dataDir + "ChangeOrientation_out.pdf";
// Save output file
doc.Save(dataDir);