Creating PDF from TIFF image using iText

Question

I'm currently generating PDF files from TIFF images using iText.

Basically the procedure is as follows: 1. Read the TIFF file. 2. For each "page" of the TIFF, instantiate an Image object and write that to a Document instance, which is the PDF file.

I'm having a hard time understanding how to add those images to the PDF keeping the original resolution.

I've tried to scale the Image to the dimensions in pixels of the original image of the TIFF, for instance:

// Pixel Dimensions 1728 × 2156 pixels
// Resolution 204 × 196 ppi
RandomAccessFileOrArray tiff = new RandomAccessFileOrArray("/path/to/tiff/file");
Document pdf = new Document(PageSize.LETTER);
Image temp = TiffImage.getTiffImage(tiff, page);
temp.scaleAbsolute(1728f, 2156f);
pdf.add(temp);

I would really appreciate if someone can shed some light on this. Perhaps I'm missing the functionality of the Image class methods...

Thanks in advance!

Answer 1

I've found that this line doesn't work well:

document.setPageSize(pageSize);

If your TIFF files only contain one image then you're better off using this instead:

RandomAccessFileOrArray ra = new RandomAccessFileOrArray(imageFilePath);
Image image = TiffImage.getTiffImage(ra, 1);
Rectangle pageSize = new Rectangle(image.getWidth(), image.getHeight());

Document document = new Document(pageSize);
PdfWriter writer = PdfWriter.getInstance(document,  new FileOutputStream(outputFileName));
writer.setStrictImageSequence(true);
document.open();
document.add(image);
document.newPage();

document.close();

This will result in a page size that fits the image size exactly, so no scaling is required.

Answer 2

I think if you scale the image then you can not retain the original resolution (please correct me if I am wrong :)). What you can try doing is to creat a PDF document with different sized pages (if images are of different resolution in the tif image).

Try the following code. It sets the size of PDF page equal to that of image file and then create that PDF page. the PDF page size varies according to the image size so the resolution is maintained :)

import java.io.FileOutputStream;
import java.io.IOException;

import com.itextpdf.text.Document;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.Image;
import com.itextpdf.text.PageSize;
import com.itextpdf.text.Paragraph;
import com.itextpdf.text.Rectangle;
import com.itextpdf.text.pdf.PdfWriter;
import com.itextpdf.text.pdf.RandomAccessFileOrArray;
import com.itextpdf.text.pdf.codec.TiffImage;

public class Tiff2Pdf {

    /**
     * @param args
     * @throws DocumentException
     * @throws IOException
     */
    public static void main(String[] args) throws DocumentException,
            IOException {

        String imgeFilename = "/home/saurabh/Downloads/image.tif";

        Document document = new Document();
        PdfWriter writer = PdfWriter.getInstance(
                document,
                new FileOutputStream("/home/saurabh/Desktop/out"
                        + Math.random() + ".pdf"));
        writer.setStrictImageSequence(true);
        document.open();

        document.add(new Paragraph("Multipages tiff file"));
        Image image;
        RandomAccessFileOrArray ra = new RandomAccessFileOrArray(imgeFilename);
        int pages = TiffImage.getNumberOfPages(ra);
        for (int i = 1; i <= pages; i++) {
            image = TiffImage.getTiffImage(ra, i);
            Rectangle pageSize = new Rectangle(image.getWidth(),
                    image.getHeight());
            document.setPageSize(pageSize);
            document.add(image);
            document.newPage();
        }

        document.close();

    }

}

Answer 3

Another example non-deprecated up to iText 5.5 with the first page issue fixed. I'm using 5.5.11 Itext.

import java.io.FileOutputStream;
import java.io.RandomAccessFile;
import java.nio.channels.FileChannel;
import com.itextpdf.text.Document;
import com.itextpdf.text.Image;
import com.itextpdf.text.Rectangle;
import com.itextpdf.text.io.FileChannelRandomAccessSource;
import com.itextpdf.text.pdf.PdfWriter;
import com.itextpdf.text.pdf.RandomAccessFileOrArray;
import com.itextpdf.text.pdf.codec.TiffImage;
public class Test1 {
    public static void main(String[] args) throws Exception {
        RandomAccessFile aFile = new RandomAccessFile("/myfolder/origin.tif", "r");
        FileChannel inChannel = aFile.getChannel();
        FileChannelRandomAccessSource fcra =  new FileChannelRandomAccessSource(inChannel);
        Document document = new Document();
        PdfWriter.getInstance(document,  new FileOutputStream("/myfolder/destination.pdf"));
        document.open();              
        RandomAccessFileOrArray rafa = new RandomAccessFileOrArray(fcra);
        int pages = TiffImage.getNumberOfPages(rafa);
        Image image;
        for (int i = 1; i <= pages; i++) {            
            image = TiffImage.getTiffImage(rafa, i);
            Rectangle pageSize = new Rectangle(image.getWidth(), image.getHeight());
            document.setPageSize(pageSize);
            document.newPage();
            document.add(image);
        }
        document.close();
        aFile.close();            
    }
}