Compress images of PDF using iTextSharpes causes Insufficient Memory

Question

Im basing the code in this thread: PDF Compression with iTextSharp

Im having an exception "Insufficient Memory", the PDF Im handling have 47 images weighting different Kb each, making the pdf 16.5mb.

The code is the same:

public void ReduceResolution(PdfReader reader, long quality)
{
    int n = reader.XrefSize;
    for (int i = 0; i < n; i++)
    {
        PdfObject obj = reader.GetPdfObject(i);
        if (obj == null || !obj.IsStream()) { continue; }

        PdfDictionary dict = (PdfDictionary)PdfReader.GetPdfObject(obj);
        PdfName subType = (PdfName)PdfReader.GetPdfObject(
          dict.Get(PdfName.SUBTYPE)
        );
        if (!PdfName.IMAGE.Equals(subType)) { continue; }

        PRStream stream = (PRStream)obj;
        try
        {
            PdfImageObject image = new PdfImageObject(stream);
            PdfName filter = (PdfName)image.Get(PdfName.FILTER);
            if (
              PdfName.JBIG2DECODE.Equals(filter)
              || PdfName.JPXDECODE.Equals(filter)
              || PdfName.CCITTFAXDECODE.Equals(filter)
              || PdfName.FLATEDECODE.Equals(filter)
            ) continue;

            System.Drawing.Image img = image.GetDrawingImage();
            if (img == null) continue;

            var ll = ImageToByteArray(img);
            int width = img.Width;
            int height = img.Height;
            using (System.Drawing.Bitmap dotnetImg =
               new System.Drawing.Bitmap(img))
            {
                // set codec to jpeg type => jpeg index codec is "1"
                System.Drawing.Imaging.ImageCodecInfo codec =
                System.Drawing.Imaging.ImageCodecInfo.GetImageEncoders()[1];
                // set parameters for image quality
                System.Drawing.Imaging.EncoderParameters eParams =
                 new System.Drawing.Imaging.EncoderParameters(1);
                eParams.Param[0] =
                 new System.Drawing.Imaging.EncoderParameter(
                   System.Drawing.Imaging.Encoder.Quality, quality
                );
                using (MemoryStream msImg = new MemoryStream())
                {
                    dotnetImg.Save(msImg, codec, eParams);
                    msImg.Position = 0;
                    stream.SetData(msImg.ToArray());
                    stream.SetData(
                     msImg.ToArray(), false, PRStream.BEST_COMPRESSION
                    );
                    stream.Put(PdfName.TYPE, PdfName.XOBJECT);
                    stream.Put(PdfName.SUBTYPE, PdfName.IMAGE);
                    stream.Put(PdfName.FILTER, filter);
                    stream.Put(PdfName.FILTER, PdfName.DCTDECODE);
                    stream.Put(PdfName.WIDTH, new PdfNumber(width));
                    stream.Put(PdfName.HEIGHT, new PdfNumber(height));
                    stream.Put(PdfName.BITSPERCOMPONENT, new PdfNumber(8));
                    stream.Put(PdfName.COLORSPACE, PdfName.DEVICERGB);
                }
            }
        }
        catch(Exception ex)
        {
            // throw ex;
            // iText[Sharp] can't handle all image types...
        }
        finally
        {
            // may or may not help      
            reader.RemoveUnusedObjects();
        }
    }
}

It happens after the 1st image, it seems the 2nd image is an x amount of bytes large enough that causes the exception.

Is there any way to avoid this type of error, what could be causing it?

Compress images of PDF using iTextSharpes causes Insufficient Memory

0 Answers0