< Android samples

ElementEditTest - Java

The sample code shows how to edit the page display list and how to modify graphics state attributes on existing Elements. In particular the sample program strips all images from the page and changes text color to blue.

//---------------------------------------------------------------------------------------
// Copyright (c) 2001-2018 by PDFTron Systems Inc. All Rights Reserved.
// Consult legal.txt regarding legal and license information.
//---------------------------------------------------------------------------------------

import com.pdftron.pdf.*;
import com.pdftron.sdf.SDFDoc;
import java.util.*;
import com.pdftron.sdf.Obj;
//---------------------------------------------------------------------------------------
// The sample code shows how to edit the page display list and how to modify graphics state 
// attributes on existing Elements. In particular the sample program strips all images from 
// the page, changes path fill color to red, and changes text color to blue. 
//---------------------------------------------------------------------------------------
public class ElementEditTest 
{
	public static void processElements(ElementWriter writer, ElementReader reader, Set<Integer> visited)
	{
		Element element;
		try 
		{
			while ((element = reader.next()) != null)
			{
				switch (element.getType())
				{
					case Element.e_image:
					case Element.e_inline_image:
						// remove all images by skipping them			
						break;
					case Element.e_path:
						{
							// Set all paths to red color.
							GState gs = element.getGState();
							gs.setFillColorSpace(ColorSpace.createDeviceRGB());
							gs.setFillColor(new ColorPt(1, 0, 0));
							writer.writeElement(element);
						}
						break;
					case Element.e_text:
						{
							// Set all text to blue color.
							GState gs = element.getGState();
							gs.setFillColorSpace(ColorSpace.createDeviceRGB());
							gs.setFillColor(new ColorPt(0, 0, 1));
							writer.writeElement(element);
						}
						break;
					case Element.e_form:
						{
							writer.writeElement(element); // write Form XObject reference to current stream
							Obj form_obj = element.getXObject();
							if (!visited.contains((int)form_obj.getObjNum())) // if this XObject has not been processed
							{
								// recursively process the Form XObject
								visited.add((int)form_obj.getObjNum());
								ElementWriter new_writer=new ElementWriter();
								reader.formBegin();
								new_writer.begin(form_obj);
								processElements(new_writer, reader, visited);
								new_writer.end();
								reader.end();
							}
						}
						break;
					default:
						writer.writeElement(element);
						break;
				}
			}
		}
		catch(Exception e)
		{
			e.printStackTrace();
		}
	}

	public static void main(String[] args) {
	
		PDFNet.initialize();

		// Relative path to the folder containing test files.
		String input_path =  "../../TestFiles/";
		String output_path = "../../TestFiles/Output/";
		String input_filename = "newsletter.pdf";
		String output_filename = "newsletter_edited.pdf";

		try  
		{
			System.out.println("Opening the input file...");
			PDFDoc doc=new PDFDoc((input_path + input_filename));
			doc.initSecurityHandler();

			ElementWriter writer=new ElementWriter();
			ElementReader reader=new ElementReader();
			Set<Integer> visited=new TreeSet<Integer>();
		
			PageIterator itr = doc.getPageIterator();
			while (itr.hasNext())
			{
				Page page = itr.next();
				visited.add((int)page.getSDFObj().getObjNum());

				reader.begin(page);
				writer.begin(page, ElementWriter.e_replacement, false);
				ElementEditTest.processElements(writer, reader, visited);
				writer.end();
				reader.end();
			}

			// Save modified document
			doc.save((output_path + output_filename), SDFDoc.SaveMode.REMOVE_UNUSED, null);
			doc.close();
			System.out.println("Done. Result saved in " + output_filename +"...");
		}
		catch(Exception e)
		{
			e.printStackTrace();
		}

		PDFNet.terminate();
	}
}