//---------------------------------------------------------------------------------------
// Copyright (c) 2001-2008 by PDFTron Systems Inc. All Rights Reserved.
// Consult legal.txt regarding legal and license information.
//---------------------------------------------------------------------------------------

import pdftron.Filters.Filter;
import pdftron.Filters.FilterReader;
import pdftron.PDF.*;
import pdftron.SDF.DictIterator;
import pdftron.SDF.Obj;
import pdftron.SDF.ObjSet;
import pdftron.SDF.SDFDoc;

// This sample project illustrates how to recompress bi-tonal images in an 
// existing PDF document using JBIG2 compression. The sample is not intended 
// to be a generic PDF optimization tool.
//
// You can download the entire document using the following link:
//   http://www.pdftron.com/net/samplecode/data/US061222892.pdf
public class JBIG2Test 
{

	public static void main(String[] args) 
	{
		PDFNet.initialize();
		PDFNet.setResourcesPath("../../../resources");
		
		try 
		{
			PDFDoc pdf_doc=new PDFDoc("../../TestFiles/US061222892-a.pdf");
			pdf_doc.initSecurityHandler();

			SDFDoc cos_doc = pdf_doc.getSDFDoc();
			int num_objs = (int)cos_doc.xRefSize();
			for(int i=1; i<num_objs; ++i) 
			{
				Obj obj = cos_doc.getObj(i);
				if(obj!=null && !obj.isFree() && obj.isStream()) 
				{
					// Process only images
					DictIterator itr = obj.find("Subtype");
					if(!itr.hasNext() || !itr.value().getName().equals("Image"))
						continue;
					
					Image input_image=new Image(obj);
					// Process only gray-scale images
					if(input_image.getComponentNum() != 1)
						continue;
					int bpc = input_image.getBitsPerComponent();
					if(bpc != 1)	// Recompress only 1 BPC images
						continue;

					// Skip images that are already compressed using JBIG2
					itr = obj.find("Filter");
					if (itr.hasNext() && itr.value().isName() && 
						!itr.value().getName().equals("JBIG2Decode")) continue; 

					Filter filter=obj.getDecodedStream();
					FilterReader reader=new FilterReader(filter);

					ObjSet hint_set=new ObjSet(); 
					Obj hint=hint_set.createArray(); // A hint to image encoder to use JBIG2 compression
					hint.pushBackName("JBIG2");
					hint.pushBackName("Lossless");

					Image new_image = Image.create(cos_doc, reader, 
						input_image.getImageWidth(), 
						input_image.getImageHeight(), 1, ColorSpace.createDeviceGray(), hint);

					Obj new_img_obj = new_image.getSDFObj();
					itr = obj.find("Decode");
					if(itr.hasNext())
						new_img_obj.put("Decode", itr.value());
					itr = obj.find("ImageMask");
					if (itr.hasNext())
						new_img_obj.put("ImageMask", itr.value());
					itr = obj.find("Mask");
					if (itr.hasNext())
						new_img_obj.put("Mask", itr.value());

					cos_doc.swap(i, new_img_obj.getObjNum());
				}
			}

			pdf_doc.save("../../TestFiles/Output/US061222892_JBIG2.pdf", SDFDoc.e_remove_unused, null);
		}
		catch(Exception e)
		{
			e.printStackTrace();
		}

		PDFNet.terminate();
	}

}