Dart Requires Chilkat v11.7.0+

Put a Letterhead Behind the First Page of a PDF

See more PDF Watermark Examples

Demonstrates the pdfPage type, which places a page of another PDF as the watermark. It is the way to use a letterhead, a cover overlay or a vector logo that was saved as a PDF, and unlike an image it stays sharp at any size because it is drawn, not resampled. "zOrder" set to back puts it behind the existing content, where a letterhead belongs, and "pages" set to first restricts it to page one. Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // This example requires the Chilkat API to have been previously unlocked.
  // See Global Unlock Sample for sample code.

  // The PDF used in this example is available at two_page_memo.pdf

  // The PDF used in this example is available at letterhead.pdf

  final pdf = CkPdf();
  try {
    pdf.loadFile('qa_data/pdf/two_page_memo.pdf');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  final json = CkJsonObject();
  json.updateString('type', 'pdfPage');
  json.updateString('pdf.path', 'qa_data/pdf/letterhead.pdf');

  // The page of the source PDF to use (1 by default).  "match" instead of a number places source
  // page n on target page n, which suits a set of per-page backgrounds.
  json.updateInt('pdf.page', 1);

  // Behind the memo's own text, on page one, scaled to the page.
  json.updateString('zOrder', 'back');
  json.updateString('pages', 'first');
  json.updateString('scale.fit', 'page');
  json.updateString('id', 'letterhead');

  final jsonOut = CkJsonObject();
  try {
    pdf.watermark('add', json, jsonOut);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('id: ${jsonOut.stringOf('id')} pages: ${jsonOut.stringOf('pages')}');

  try {
    pdf.writeFile('qa_output/memo_letterhead.pdf');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Sample output:

  // id: letterhead pages: 1
}