Question

我正在使用 PdfSharp 修改 Pdf 文件。我有一个现有的 pdf，其中包含表格格式的数据。

我想知道 PdfSharp 中是否有任何内容可以将 DocumentLink 添加到这些现有元素中？

或者类似的东西，我可以从中确定每个文本的 X 和 Y，然后我可以在其上渲染 Rect 并可以在其上添加 DocumentLink？

外部pdf文件真的可以做到这一点吗？

Answer 1

是的，这是可能的。我下面的代码只是创建一个 pdf 文档，添加两行文本。第一行是链接文本，第二行是链接操作的目标文本。

    static void Main(string[] args)
    {
        string doc1 = @"C:\doc1.pdf";

        CreatePdf(doc1);

        CSequence contents;

        using (var doc = PdfReader.Open(doc1, PdfDocumentOpenMode.Modify))
        {

            AddDocumentLink(doc, page);

            doc.Save(doc1);
            doc.Close();
        }

        Process.Start(doc1);

    }

    public static void CreatePdf(string filename)
    {
        // Create a new PDF document
        PdfDocument document = new PdfDocument();
        document.Info.Title = "Created with PDFsharp";

        // Create an empty page
        PdfPage page = document.AddPage();

        AddTextToPage(page);

        // Save the document...
        document.Save(filename);
        // ...and start a viewer.
    }

    public static void AddTextToPage(PdfPage page)
    {
        // Get an XGraphics object for drawing
        XGraphics gfx = XGraphics.FromPdfPage(page);

        // Create a font
        XFont font = new XFont("Verdana", 20, XFontStyle.BoldItalic, new XPdfFontOptions(PdfFontEncoding.WinAnsi));

        // Draw the text
        gfx.DrawString("Click here to go to [Hello, World!]", font, XBrushes.Black,
          new XRect(0, 0, page.Width, page.Height),
          XStringFormats.TopCenter);

        gfx.DrawString("Hello, World!", font, XBrushes.Black,
          new XRect(0, 0, page.Width, page.Height),
          XStringFormats.Center);
    }

    // Please refer to the pdf tech specs on what all entails in the content stream
    // https://www.adobe.com/content/dam/acom/en/devnet/pdf/pdfs/PDF32000_2008.pdf
    public static void AddDocumentLink(PdfDocument pdf, PdfPage page)
    {
        PdfContents contents = page.Contents;
        if (contents != null && contents.Elements.Count > 0)
        {

            CSequence pageContents = ContentReader.ReadContent(page);
            int numOfContentElements = pageContents.Count;

            COperator currentElement = null;
            COperator previousElement = null;
            COperator nextElement = null;

            double xLink = 0;
            double yLink = 0;
            double xDest = 0;
            double yDest = 0;

            for (int j = 0; j < numOfContentElements; j++)
            {
                currentElement = (COperator)pageContents[j];

                if (j > 0)
                    previousElement = (COperator)pageContents[j - 1];
                if (j > 0 && j + 1 < numOfContentElements)
                    nextElement = (COperator)pageContents[j + 1];

                // get coordinates for the text to create link for
                if (currentElement.OpCode.OpCodeName == OpCodeName.Td
                && nextElement != null
                    && nextElement.OpCode.OpCodeName == OpCodeName.Tj
                    && nextElement.Operands[0] is CString
                    && ((CString)nextElement.Operands[0]).Value.Contains("Click here"))
                {
                    xLink = ((CReal)currentElement.Operands[0]).Value;
                    yLink = ((CReal)currentElement.Operands[1]).Value;

                }

                // get coordinates of Hello World text
                if (currentElement.OpCode.OpCodeName == OpCodeName.Td
                    && nextElement != null
                    && nextElement.OpCode.OpCodeName == OpCodeName.Tj
                    && nextElement.Operands[0] is CString
                    && ((CString)nextElement.Operands[0]).Value.StartsWith("Hello World"))
                {
                    xDest = ((CReal)currentElement.Operands[0]).Value;
                    yDest = ((CReal)currentElement.Operands[1]).Value;

                }

            }
        
        
            // Create a link annotation
            pdf.AddNamedDestination("GotoHello", 1, PdfNamedDestinationParameters.CreatePosition(xDest, yDest, 1));
            page.AddDocumentLink(new PdfRectangle(new XRect(xLink, yLink, 300, 25)), "GotoHello");
        }


    }

最好的，理由

使用 PdfSharp 将文档链接添加到现有的 Pdf 文件

1 个答案: