Xfinium PDF：无法保存 pdf 文件。 接收错误根缺失条目

Question

I have a problem saving the Xfinium PDF. I loaded a document and simply draw the line across the page and save. The file generated but when I used that file and loaded back to PdfFixedDocument I have the error

Root entry is missing in file trailer

My code is very simple:

var pdf = new PdfFixedDocument (document.Location);
        var page = pdf.Pages [pageIndex];
        var graphics = page.Graphics;
        var directory = FileUtilities.GetExternalPrivateDirectory (PdfCore.CACHE_DIRECTORY);
        //var png = FileUtilities.GetFile (directory + "/test.pdf");  
        //var rawStream = File.OpenWrite (png.AbsolutePath);
        var stream = new FileStream (directory + "/test.pdf", FileMode.Create);
        pdf.BeginSave (stream);

        graphics.DrawLine(new Xfinium.Pdf.Graphics.PdfPen (),
            new Xfinium.Pdf.Graphics.PdfPoint (0,0),
            new Xfinium.Pdf.Graphics.PdfPoint (page.Width, page.Height));

        page.SaveGraphics (); 

        pdf.EndSave ();

Answer 1

Instead of manually creating the stream and using BeginSave / EndSave , just try using Save :

var pdf = new PdfFixedDocument();
var page = pdf.Pages.Add();
var graphics = page.Graphics;
                graphics.DrawLine(new Xfinium.Pdf.Graphics.PdfPen(),
    new Xfinium.Pdf.Graphics.PdfPoint(0, 0),
    new Xfinium.Pdf.Graphics.PdfPoint(page.Width, page.Height));
var directory = Environment.GetExternalStoragePublicDirectory(Environment.DirectoryDownloads);
pdf.Save(Path.Combine(directory.Path, "test.pdf"));

Java.IO.File pdfFILE = new Java.IO.File(Path.Combine(directory.Path, "test.pdf"));
Intent intent = new Intent(Intent.ActionView);
intent.SetDataAndType(Uri.FromFile(pdfFILE), "application/pdf");
StartActivity(intent);

Answer 2

I believe that the PDF document is not properly written to file because the stream is not closed. Try adding these lines at the end of your code (after pdf.EndSave()):

stream.Flush();
stream.Close();

The BeginSave/SaveGraphics/EndSave mode should be used when creating pages with heavy content, such as vector maps, and you want to reduce memory consumption by calling SaveGraphics after drawing a certain number of graphic objects (SaveGraphics can be called multiple times for a page).

For your scenario you can simplify the code as follows (like SushiHangover suggested):

var pdf = new PdfFixedDocument (document.Location);
var page = pdf.Pages [pageIndex];
var graphics = page.Graphics;

graphics.DrawLine(new Xfinium.Pdf.Graphics.PdfPen (),
    new Xfinium.Pdf.Graphics.PdfPoint (0,0),
    new Xfinium.Pdf.Graphics.PdfPoint (page.Width, page.Height));

var directory = FileUtilities.GetExternalPrivateDirectory(PdfCore.CACHE_DIRECTORY);
pdf.Save(directory + "/test.pdf");

Disclaimer: I work for the company that develops XFINIUM.PDF library.

Answer 3

.Save (document path) is massively slow when it comes to eg: 100 pages and lots of data so the end file has about 145MB or more, then the saving operation takes 2 minutes pls - this is ways to slow so I will try the BeginSave and EndSave approach also