Some test text!

< Android samples

ElementEditTest - Java (Android)

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.
//---------------------------------------------------------------------------------------

package com.pdftron.android.pdfnetsdksamples.samples;

import com.pdftron.android.pdfnetsdksamples.OutputListener;
import com.pdftron.android.pdfnetsdksamples.PDFNetSample;
import com.pdftron.android.pdfnetsdksamples.R;
import com.pdftron.android.pdfnetsdksamples.util.Utils;
import com.pdftron.pdf.ColorPt;
import com.pdftron.pdf.ColorSpace;
import com.pdftron.pdf.Element;
import com.pdftron.pdf.ElementReader;
import com.pdftron.pdf.ElementWriter;
import com.pdftron.pdf.GState;
import com.pdftron.pdf.PDFDoc;
import com.pdftron.pdf.Page;
import com.pdftron.pdf.PageIterator;
import com.pdftron.sdf.Obj;
import com.pdftron.sdf.SDFDoc;

import java.io.File;
import java.util.ArrayList;
import java.util.Set;
import java.util.TreeSet;

public class ElementEditTest extends PDFNetSample {

	private static OutputListener mOutputListener;

	private static ArrayList<String> mFileList = new ArrayList<>();

    public ElementEditTest() {
        setTitle(R.string.sample_elementedit_title);
        setDescription(R.string.sample_elementedit_description);
    }

	@Override
	public void run(OutputListener outputListener) {
		super.run(outputListener);
		mOutputListener = outputListener;
		mFileList.clear();
		printHeader(outputListener);

        String input_filename = "newsletter.pdf";
        String output_filename = "newsletter_edited.pdf";

        try {
            mOutputListener.println("Opening the input file...");
            PDFDoc doc = new PDFDoc((Utils.getAssetTempFile(INPUT_PATH + input_filename).getAbsolutePath()));
            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);
                processElements(writer, reader, visited);
                writer.end();
                reader.end();
            }

            // Save modified document
            doc.save(Utils.createExternalFile(output_filename).getAbsolutePath(), SDFDoc.SaveMode.REMOVE_UNUSED, null);
            mFileList.add(new File(doc.getFileName()).getName());
            doc.close();
            mOutputListener.println("Done. Result saved in " + output_filename + "...");
        } catch (Exception e) {
            e.printStackTrace();
        }

		for (String file : mFileList) {
			addToFileList(file);
		}
		printFooter(outputListener);
	}
    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();
        }
    }

}