Imposition

Sample C# code for using Apryse SDK to impose (combine) multiple PDF pages. Page imposition can be used to arrange/order pages prior to printing or for document assembly (assemble a 'master' page from several 'source' pages). It is also possible to write applications that can re-order the pages such that they will display in the correct order when the hard copy pages are compiled and folded correctly. Learn more about our Xamarin SDK and PDF Editing & Manipulation Library.

C#

//---------------------------------------------------------------------------------------
// Copyright (c) 2001-2021 by PDFTron Systems Inc. All Rights Reserved.
// Consult legal.txt regarding legal and license information.
//---------------------------------------------------------------------------------------
using System;
using System.IO;
using System.Collections;
using pdftron;
using pdftron.Common;
using pdftron.SDF;
using pdftron.PDF;

//-----------------------------------------------------------------------------------
// The sample illustrates how multiple pages can be combined/imposed 
// using PDFNet. Page imposition can be used to arrange/order pages 
// prior to printing or to assemble a 'master' page from several 'source' 
// pages. Using PDFNet API it is possible to write applications that can 
// re-order the pages such that they will display in the correct order 
// when the hard copy pages are compiled and folded correctly. 
//-----------------------------------------------------------------------------------

using NUnit.Framework;

namespace MiscellaneousSamples
{
	[TestFixture]
	public class ImpositionTest
	{
		
		[Test]
		public static void Sample()
		{

			// Relative path to the folder containing test files.
			const string input_path =  "TestFiles/";

			try	
			{    
				Console.WriteLine("-------------------------------------------------");
				Console.WriteLine("Opening the input pdf...");
				using (PDFDoc in_doc = new PDFDoc(Utils.GetAssetTempFile(input_path + "newsletter.pdf")))
				{
					in_doc.InitSecurityHandler();

					// Create a list of pages to import from one PDF document to another.
					ArrayList import_list = new ArrayList(); 
					for (PageIterator itr = in_doc.GetPageIterator(); itr.HasNext(); itr.Next()) 
						import_list.Add(itr.Current());

					using (PDFDoc new_doc = new PDFDoc()) //  Create a new document
					using (ElementBuilder builder = new ElementBuilder())
					using (ElementWriter  writer  = new ElementWriter())
					{
						ArrayList imported_pages = new_doc.ImportPages(import_list);

						// Paper dimension for A3 format in points. Because one inch has 
						// 72 points, 11.69 inch 72 = 841.69 points
						Rect media_box= new Rect(0, 0, 1190.88, 841.69); 
						double mid_point = media_box.Width()/2;

						for (int i=0; i<imported_pages.Count; ++i)
						{
							// Create a blank new A3 page and place on it two pages from the input document.
							Page new_page = new_doc.PageCreate(media_box);
							writer.Begin(new_page);

							// Place the first page
							Page src_page = (Page)imported_pages[i];
							Element element = builder.CreateForm(src_page);

							double sc_x = mid_point / src_page.GetPageWidth();
							double sc_y = media_box.Height() / src_page.GetPageHeight();
							double scale = Math.Min(sc_x, sc_y);
							element.GetGState().SetTransform(scale, 0, 0, scale, 0, 0);
							writer.WritePlacedElement(element);

							// Place the second page
							++i; 
							if (i<imported_pages.Count)	
							{
								src_page = (Page)imported_pages[i];
								element = builder.CreateForm(src_page);
								sc_x = mid_point / src_page.GetPageWidth();
								sc_y = media_box.Height() / src_page.GetPageHeight();
								scale = Math.Min(sc_x, sc_y);
								element.GetGState().SetTransform(scale, 0, 0, scale, mid_point, 0);
								writer.WritePlacedElement(element);
							}

							writer.End();
							new_doc.PagePushBack(new_page); 
						}
						new_doc.Save(Utils.CreateExternalFile("newsletter_booklet.pdf"), SDFDoc.SaveOptions.e_linearized);
						Console.WriteLine("Done. Result saved in newsletter_booklet.pdf...");
					}
				}
			}
			catch (Exception e)
			{
				Console.WriteLine("Exception caught:\n{0}", e);
				Assert.True(false);
			}
		}
	}
}