c# How to return a byte array from pdf using iTextsharp

问题

All,

i created the following method to take in a tiff byte array with multiple tiff page document

i need to convert this to pdf, then return a pdf byte array

i have 2 problems with this code 1 - i want to RETURN a byte []. 2 - the pdf generated is repeating the pages.

    public void convertImage(byte[] documentContent)
    {
        Document document = new Document(PageSize.LETTER, 0, 0, 0, 0);

        PdfWriter writer = PdfWriter.GetInstance(document, new FileStream(@"C:\Data\Output.pdf", FileMode.Create)); --for testing purposes



        Bitmap oldImage;

        using (var ms = new MemoryStream(documentContent))
        {
            oldImage = new Bitmap(ms);
        }


        Size newSize = new Size(1024, 737);


        using (Bitmap bmp1 = new Bitmap(oldImage, newSize))
        {
            int total = oldImage.GetFrameCount(FrameDimension.Page);

            document.Open();

            PdfContentByte cb = writer.DirectContent;

            for (int k = 0; k < total; ++k)
            {
                bmp1.SelectActiveFrame(FrameDimension.Page, k);

                iTextSharp.text.Image img = iTextSharp.text.Image.GetInstance(bmp1, ImageFormat.Bmp);

                var scaleparcent = 72f / img.DpiX * 100;

                img.ScalePercent(scaleparcent);

                img.ScaleAbsoluteHeight(document.PageSize.Height);
                img.ScaleAbsoluteWidth(document.PageSize.Width);

                img.SetAbsolutePosition(0, 0);

                cb.AddImage(img);

                document.NewPage();

            }
        }

        byte[] bytes = null;

        document.Close();
    }

some one help please?

回答1:

This is a basic example:

private byte[] CreatePdf()
{
    Document document = new Document();
    using (MemoryStream ms = new MemoryStream())
    {
        PdfWriter.GetInstance(document, ms);
        document.Open();
        document.Add(new Paragraph("Hello World"));
        document.Close();
        return ms.ToArray();
    }
}

It is similar to a previous answer, but in that answer in isn't made clear that you need to Close() the document instance before you get the bytes from the MemoryStream. In your code snippet, you have:

byte[] bytes = null;
document.Close();

Based on the previous answer, you might change this into:

byte[] bytes = ms.ToArray();
document.Close();

That would be wrong, because the bytes array wouldn't contain the full PDF. Upon document.Close(), a lot of essential data is written to the output stream (the info dictionary, the root dictionary, the cross-reference table).

Update:

In C#, it is custom to use using as indicated in the comments:

private byte[] CreatePdf()
{
    using (MemoryStream ms = new MemoryStream())
    {
        using (Document document = new Document())
        {
            PdfWriter.GetInstance(document, ms);
            document.Open();
            document.Add(new Paragraph("Hello World"));
        }
        return ms.ToArray();
    }
}

My argument that the document needs to be closed to get a complete PDF remains valid: the document instance is closed implicitly by the } right before return ms.ToArray().

来源：https://stackoverflow.com/questions/37095802/c-sharp-how-to-return-a-byte-array-from-pdf-using-itextsharp

标签

pdf

itextsharp

tiff