如何在保持iTextSharp方向的同時縮放PDF頁面？

Question

如何在保持itextsharp中的旋轉的同時縮放PDF頁面？ 我有以下的，但我失去了旋轉：

public static void ScaleToLetter(string inPDF, string outPDF) 
    { 
     PdfReader reader = new PdfReader(inPDF); 
     Document doc = new Document(PageSize.LETTER); 
     Document.Compress = true; 
     PdfWriter writer = PdfWriter.GetInstance(doc, 
      new FileStream(outPDF, FileMode.Create)); 
     doc.Open(); 
     PdfContentByte cb = writer.DirectContent; 
     int rotation; 

     PdfImportedPage page; 
     for (int pageNumber = 1; pageNumber <= reader.NumberOfPages; pageNumber++) 
     { 
      page = writer.GetImportedPage(reader, pageNumber); 
      rotation = reader.GetPageRotation(pageNumber); 

      cb.AddTemplate(page, 
       PageSize.LETTER.Width/reader.GetPageSize(pageNumber).Width, 
       0, 0, 
       PageSize.LETTER.Height/reader.GetPageSize(pageNumber).Height, 
       0, 0); 
      doc.NewPage(); 
     } 
     doc.Close(); 
    } 

Answer 1

我也有類似的問題，並得到了它通過改變每個頁面的高度和寬度，從信LETTER旋轉的工作。換句話說，如果當前頁面很薄很高，那麼它就是垂直的。但是，如果它是寬和短，那麼它是水平的，我應該旋轉頁面。

這是你的代碼改變：

public static void ScaleToLetter(string inPDF, string outPDF) 
    { 
     PdfReader reader = new PdfReader(inPDF); 
     Document doc = new Document(PageSize.LETTER); 
     Document.Compress = true; 
     PdfWriter writer = PdfWriter.GetInstance(doc, 
      new FileStream(outPDF, FileMode.Create)); 
     doc.Open(); 
     PdfContentByte cb = writer.DirectContent; 

     PdfImportedPage page; 
     for (int pageNumber = 1; pageNumber <= reader.NumberOfPages; pageNumber++) 
     { 
      page = writer.GetImportedPage(reader, pageNumber); 

      if (page.Width <= page.Height) 
       doc.SetPageSize(PageSize.LETTER); 
      else 
       doc.SetPageSize(PageSize.LETTER.Rotate()); 
      doc.NewPage(); 

      cb.AddTemplate(page, 
       doc.PageSize.Width/reader.GetPageSize(pageNumber).Width, 
       0, 0, 
       doc.PageSize.Height/reader.GetPageSize(pageNumber).Height, 
       0, 0); 
     } 
     doc.Close(); 
    } 

我也需要限制的地步，所以我結束了這一點：

public static void ScaleToA4(string inPDF, string outPDF) 
    { 
     var reader = new PdfReader(new MemoryStream(File.ReadAllBytes(inPDF))); 
     var document = new Document(PageSize.A4); 
     var ms = new MemoryStream(); 
     var writer = PdfWriter.GetInstance(document, ms); 
     document.Open(); 
     var cb = writer.DirectContent; 

     for (var pageNumber = 1; pageNumber <= reader.NumberOfPages; pageNumber++) 
     { 
      var page = writer.GetImportedPage(reader, pageNumber); 
      document.SetPageSize(page.Width <= page.Height ? 
       PageSize.A4 : PageSize.A4.Rotate()); 
      document.NewPage(); 

      var widthFactor = document.PageSize.Width/page.Width; 
      var heightFactor = document.PageSize.Height/page.Height; 
      var factor = Math.Min(widthFactor, heightFactor); 

      var offsetX = (document.PageSize.Width - (page.Width * factor))/2; 
      var offsetY = (document.PageSize.Height - (page.Height * factor))/2; 
      cb.AddTemplate(page, factor, 0, 0, factor, offsetX, offsetY); 
     } 
     document.Close(); 
     File.WriteAllBytes(outPDF, ms.GetBuffer()); 
    }