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abcpdf

Converting PDF to Grayscale pdf using ABC PDF

I am trying convert PDF to grayscale(Black/White) PDF using Websupergoo ABCpdf.
I am referring

http://www.websupergoo.com/helppdfnet/source/8-abcpdf.operations/3-recoloroperation/1-methods/recolor.htm?q=recoloroperation 

        Doc theDoc = new Doc();
        theDoc.Read(Server.MapPath("src.pdf"));
        int pages = theDoc.PageCount;
       MyOp.Recolor(theDoc, (WebSupergoo.ABCpdf8.Objects.Page)theDoc.ObjectSoup[theDoc.Page]); //Here problem
      theDoc.Save(Server.MapPath("greyscale1.pdf"));
        theDoc.Clear();

Above code works fine for single page PDf.

This Code Converts only first page of PDF

When I tried to use a loop the below error is occurring

Code With error

Solution

  • Page Number is not the same as Page in abcPDF, so you cannot use the page number as an index into the object soup.

    Try something like this instead (untested):

    int pages = theDoc.PageCount;
for(int i=0; i < pages; i++)
{
    theDoc.PageNumber = i;
    MyOp.Recolor(theDoc, (WebSupergoo.ABCpdf8.Objects.Page)theDoc.ObjectSoup[theDoc.Page]);
}

    Edit: The above apparently didn't work, but as the documentation you linked to shows, there's a method that takes a Doc object instead of a Page object. This should work if you change your MyOp.Recolor() method to this:

    public class MyOp
{
  public static void Recolor(Doc doc) {
    RecolorOperation op = new RecolorOperation();
    op.DestinationColorSpace = new ColorSpace(doc.ObjectSoup, ColorSpaceType.DeviceGray);
    op.ConvertAnnotations = false;
    op.ProcessingObject += Recoloring;
    op.ProcessedObject += Recolored;
    op.Recolor(doc);
  }
}

    I am not sure what you are doing (or need to do) in the Recoloring() method or Recolored() method, but that should not matter for the changes here.