PDFtoolkit VCL
Edit, enhance, secure, merge, split, view, print PDF and AcroForms documents

Compatibility

Delphi C++Builder

Home » Newsletter » July 2009

By V. Subhash

Yes, you can use PDFtoolkit to identify blank pages in a PDF document. The content extraction method TgtPDFDocument.GetPageElements can identify and extract PDF page elements in a specified page. The method returns the page elements in a special list of type TgtPDFPageElementList. You can loop through all pages in a document and check the count of the list returned by GetPageElements method in each iteration. When the count is zero, then the current page is blank. Here is how it is done.

program FindBlankPages;

{$APPTYPE CONSOLE}

uses
  SysUtils,
  gtCstPDFDoc,
  gtPDFClasses,
  gtExPDFDoc,
  gtExProPDFDoc,
  gtPDFDoc;

var
  gtPDFDocument1: TgtPDFDocument;
  gtPDFPageElementList1: TgtPDFPageElementList;
  I: Integer;

begin
  // Create a PDF document object
  gtPDFDocument1 := TgtPDFDocument.Create(Nil);
  try
    // Load a document
    gtPDFDocument1.LoadFromFile('doc_with_blank_pages.pdf');

    // Check if the document is loaded
    if gtPDFDocument1.IsLoaded then

     // Sift through all pages in the document
     for I := 1 to gtPDFDocument1.PageCount do
     begin
       // Load the list with all text and image elements in 
       // the current page
       gtPDFPageElementList1
         := gtPDFDocument1.GetPageElements(I,
                                           [etText, etimage],
                                           muPixels);
       // Check if a page has no text or image elements 
       if gtPDFPageElementList1.Count = 0 then
         // We have a winner - a blank page!
         Writeln('Searching page #'
                   + IntToStr(i)
                   + '... This page is BLANK.')
       else
         // The current page is not blank.
         Writeln('Searching page #'
                   + IntToStr(i)
                   + '... This page has '
                   + IntToStr(gtPDFPageElementList1.Count)
                   + ' page/image elements.');

       // Remember to clear the list
       gtPDFPageElementList1.Clear;
     end;

  except on Err: exception do
   Writeln('Error: ' + Err.Message);
  end;
  // Clean up
  FreeAndNil(gtPDFPageElementList1);
  gtPDFDocument1.Reset;
  FreeAndNil(gtPDFDocument1);

  Writeln('Press Enter key to exit.');
  Readln;
end.

After you detect a blank page, you can as mentioned earlier write a "This page is intentionally left blank." message on it. Or, you can simply delete the page. Of course, with PDFtoolkit, you have more choices than that. Have fun.