C# – iTextsharp – PDF file size after inserting image

citextsharppdf-generation

I'm currently converting some legacy code to create PDF files using iTextSharp. We're creating a largish PDF file that contains a number of images, which I'm inserting like so:

Document doc = new Document(PageSize.A4, 50, 50, 25, 25);
PdfWriter writer = PdfWriter.GetInstance(doc, myStream);

writer.SetFullCompression();

doc.Open();

Image frontCover = iTextSharp.text.Image.GetInstance(@"C:\MyImage.png");

//Scale down from a 96 dpi image to standard itextsharp 72 dpi
frontCover.ScalePercent(75f);

frontCover.SetAbsolutePosition(0, 0);

doc.Add(frontCover);

doc.Close();

Inserting an image (20.8 KB png file) seems to increase the PDF file size by nearly 100 KB.

Is there a way of compressing the image before entry (bearing in mind that this needs to be of reasonable print quality), or of further compressing the entire PDF? Am I even performing any compression in the above example?

Best Answer

The answer appears to have been that you need to set an appropriate version of the PDF spec to target and then set the compression as follows:

PdfWriter writer = PdfWriter.GetInstance(doc, ms);
PdfContentByte contentPlacer;

writer.SetPdfVersion(PdfWriter.PDF_VERSION_1_5);

writer.CompressionLevel = PdfStream.BEST_COMPRESSION;

This has brought my file size down considerably. I also found that PNG's were giving me the best results as regards to final size of document.

Related Solutions

Saving a photoshop document as a .pdf results in blurry / pixelated images

I realize this question is a few years old but thought I'd offer a possible solution for anyone else having this issue. It isn't perfect but it produced much better results than anything else I've tried so far.

Note: this is assuming you're working off of a 72ppi Photoshop document (I'm using CS5).

First ensure you have a PDF printer installed.
Then in Photoshop go to File > Print and select the aforementioned printer.
Click "Print Settings..." and select "High Quality Print" from the default settings box. (Or click "Edit" to the right and make sure your image quality is set to max).
Still in the print settings dialog, go down to "Adobe PDF Page Size:" and click "Add.."
Name your new paper size "doc" (or whatever you want really).
Then for the size divide your document width by 109 (ppi) and your height by 109 (again ppi) and enter the resulting values in their respective locations (making sure inches is selected).
Click "Add/modify" to close the dialog. Make sure your new paper size is selected from the "Adobe PDF Page Size" dropdown and hit "OK."
In the "Scaled Print Size" box area change the scale to 66% (which should make the print resolution read 109 PPI).
Click "Print", save your document and hopefully your PDF looks much better!

As a side note, you could try using 110ppi instead, calculating your size and changing the scale to 65% to match. But from my experience, for whatever reason, 109 worked better.

If you're wondering how this helps, Adobe Reader/Acrobat tend to display PDF's at 110ppi by default, so by creating the PDF to reflect this (yes, it's 1ppi off) it looks 100% at 100%.

Again, this is what worked for me, hopefully you have the same luck.

C# – iTextSharp Password Protected PDF

Yes, there are two passwords that you can pass to PdfEncryptor.Encrypt(), userPassword and ownerPassword. Just pass null to the userPassword and people will be able to open it without specify a password.

        string WorkingFolder = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
        string InputFile = Path.Combine(WorkingFolder, "Test.pdf");
        string OutputFile = Path.Combine(WorkingFolder, "Test_enc.pdf");

        using (Stream input = new FileStream(InputFile, FileMode.Open, FileAccess.Read, FileShare.Read))
        {
            using (Stream output = new FileStream(OutputFile, FileMode.Create, FileAccess.Write, FileShare.None))
            {
                PdfReader reader = new PdfReader(input);
                PdfEncryptor.Encrypt(reader, output, true, null, "secret", PdfWriter.ALLOW_SCREENREADERS);
            }
        }

Best Answer

Related Solutions

Saving a photoshop document as a .pdf results in blurry / pixelated images

C# – iTextSharp Password Protected PDF

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