How to remove one indirectly referenced image from a PDF and keep all others? - pdf

Question

I would like to parse a PDF and find the logo via known attributes and when I find a match, remove that image and then copy everything else.
I am using the code below to replace an image with a blank white image to remove a logo from PDFs that are to be printed on letterhead. It replaces the image with a white image of the same size. Is there a way to modify this to actually remove the image (and thus save some space, etc.?).
private static void Main(string[] args)
{
ManipulatePdf(#"C:\in.pdf", #"C:\out.pdf");
Console.WriteLine("Finished - press a key");
Console.ReadKey();
}
public static void ManipulatePdf(String src, String dest)
{
Console.WriteLine("Start");
PdfReader reader = new PdfReader(src);
// first read all references and find the one we wish to work on.
PdfDictionary page = reader.GetPageN(1); // all resources are available to every page (?)
PdfDictionary resources = page.GetAsDict(PdfName.RESOURCES);
PdfDictionary xobjects = resources.GetAsDict(PdfName.XOBJECT);
page = reader.GetPageN(1);
resources = page.GetAsDict(PdfName.RESOURCES);
xobjects = resources.GetAsDict(PdfName.XOBJECT);
foreach (PdfName pdfName in xobjects.Keys)
{
PRStream stream = (PRStream) xobjects.GetAsStream(pdfName);
if (stream.Length > 100000)
{
PdfImage image = new PdfImage(MakeBlankImg(), "", null);
Console.WriteLine("Calling replace stream");
ReplaceStream(stream, image);
}
}
PdfStamper stamper = new PdfStamper(reader, new FileStream(dest, FileMode.Create));
stamper.Close();
reader.Close();
}
public static iTextSharp.text.Image MakeBlankImg()
{
Console.WriteLine("Making small blank image");
byte[] array;
using (MemoryStream ms = new MemoryStream())
{
//var drawingImage = image.GetDrawingImage();
using (Bitmap newBi = new Bitmap(1, 1))
{
using (Graphics g = Graphics.FromImage(newBi))
{
g.Clear(Color.White);
g.Flush();
}
newBi.Save(ms, ImageFormat.Jpeg);
}
array = ms.ToArray();
}
Console.WriteLine("Image array is " + array.Length + " bytes.");
return iTextSharp.text.Image.GetInstance(array);
}
public static void ReplaceStream(PRStream orig, PdfStream stream)
{
orig.Clear();
MemoryStream ms = new MemoryStream();
stream.WriteContent(ms);
orig.SetData(ms.ToArray(), false);
Console.WriteLine("Iterating keys");
foreach (KeyValuePair<PdfName, PdfObject> keyValuePair in stream)
{
Console.WriteLine("Key: " + keyValuePair.Key.ToString());
orig.Put(keyValuePair.Key, stream.Get(keyValuePair.Key));
}
}
}