Create an Outline in PDF ​

// Init Methods
- (instancetype)initWithDocument:(CPDFDocument *)document {
  CPDFDocument *myDocument = document;
  [self createOutline:myDocument];
}

// Create outline
- (void)createOutline:(CPDFDocument *)oldDocument {
  NSString *commandLineStr = @""
  
  // Get Sandbox path for saving the PDF File
  NSString *path = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"];
  NSString *writeDirectoryPath = [NSString stringWithFormat:@"%@/%@", path, @"Outline"];

  if (![[NSFileManager defaultManager] fileExistsAtPath:writeDirectoryPath])
      [[NSFileManager defaultManager] createDirectoryAtURL:[NSURL fileURLWithPath:writeDirectoryPath] withIntermediateDirectories:YES attributes:nil error:nil];
  NSString *writeFilePath = [NSString stringWithFormat:@"%@/%@.pdf",writeDirectoryPath,@"CreateOutlineTest"];

  // Save the document in the test PDF file
  NSURL *outlineURL = [NSURL fileURLWithPath:writeFilePath];
  [oldDocument writeToURL:outlineURL];

  // Create a new document for test PDF file
  CPDFDocument *document = [[CPDFDocument alloc] initWithURL:outlineURL];

  // Create outline root
  [document setNewOutlineRoot];

  // Get root from PDF document
  CPDFOutline *outline = [document outlineRoot];

  // Insert a new outline node and set the outline title
  CPDFOutline *outlinePage1 = [outline insertChildAtIndex:0];
  outlinePage1.label = @"1. page1";

  CPDFOutline *outlinePage2 = [outline insertChildAtIndex:1];
  outlinePage2.label = @"2. page2";

  CPDFOutline *outlinePage3 = [outline insertChildAtIndex:2];
  outlinePage3.label = @"3. page3";

  CPDFOutline *outlinePage4 = [outline insertChildAtIndex:3];
  outlinePage4.label = @"4. page4";

  CPDFOutline *outlinePage5 = [outline insertChildAtIndex:4];
  outlinePage5.label = @"5. page5";

  // Insert secondary directory and set outline text
  CPDFOutline *outlinePage1_1 = [outlinePage1 insertChildAtIndex:0];
  outlinePage1_1.label = @"1.1 page1_1";

  // Save the create outline action in document
  [document writeToURL:outlineURL];

  commandLineStr = [commandLineStr stringByAppendingString:@"Done.\n"];
  commandLineStr = [commandLineStr stringByAppendingString:@"Done. Results saved in CreateOutlineTest.pdf\n"];
  
  [self printOutline:document];
}

// Print document outline information
- (void)printOutline:(CPDFDocument *)document {
    // Get root from PDF document
    CPDFOutline *outline = [document outlineRoot];
    
    // Get subdirectory from root
    [self loadOutline:outline level:0];
}

// Get subdirectory from root
- (void)loadOutline:(CPDFOutline *)outline level:(NSInteger)level {
    NSString *commandLineStr = @""  
  
    for (int i=0; i<[outline numberOfChildren]; i++) {
        CPDFOutline *data = [outline childAtIndex:i];
        CPDFDestination *destination = [data destination];
        if (!destination) {
            CPDFAction *action = [data action];
            if (action && [action isKindOfClass:[CPDFGoToAction class]]) {
                destination = [(CPDFGoToAction *)action destination];
            }
        }
        
        // The previous level directory will be one \t away from the previous level directory
        NSString *intervalStr = @"";
        for (int j = 0; j < level; j++) {
            commandLineStr = [self.commandLineStr stringByAppendingString:@"\t"];
        }
        commandLineStr = [self.commandLineStr stringByAppendingFormat:@"%@->%@\n", intervalStr, data.label];

        [self loadOutline:data level:level+1];
    }
}