Visual signature with pdfbox 1.8.8

Question

I'm trying to produce PDF with visual signature and pdfbox. I have two streams and it seems that pdfbox can deal only with files. I didn't manage to make it work without three temporary files. I can see from here that API has changed, but still it deals with files.

public void signPdf(InputStream originalPdf, OutputStream signedPdf,
        InputStream image, float x, float y,
        String name, String location, String reason) {

    File temp = null;
    File temp2 = null;
    File scratchFile = null;
    RandomAccessFile randomAccessFile = null;
    OutputStream tempOut = null;
    InputStream tempIn = null;
    try {
        /* Copy original to temporary file */
        temp = File.createTempFile("signed1", ".tmp");
        tempOut = new FileOutputStream(temp);
        copyStream(originalPdf, tempOut);
        tempOut.close();

        /* Read temporary file to second temporary file and stream */
        tempIn = new FileInputStream(temp);
        temp2 = File.createTempFile("signed2", ".tmp");
        tempOut = new FileOutputStream(temp2);
        copyStream(tempIn, tempOut);
        tempIn.close();
        tempIn = new FileInputStream(temp2);

        scratchFile = File.createTempFile("signed3", ".bin");
        randomAccessFile = new RandomAccessFile(scratchFile, "rw");

        /* Read temporary file */
        PDDocument document = PDDocument.load(temp, randomAccessFile);
        document.getCurrentAccessPermission().setCanModify(false);

        PDSignature signature = new PDSignature();
        signature.setFilter(PDSignature.FILTER_ADOBE_PPKLITE);
        signature.setSubFilter(PDSignature.SUBFILTER_ADBE_PKCS7_DETACHED);
        signature.setName(name);
        signature.setLocation(location);
        signature.setReason(reason);
        signature.setSignDate(Calendar.getInstance());

        PDVisibleSignDesigner signatureDesigner = new PDVisibleSignDesigner(
                document, image, document.getNumberOfPages());
        signatureDesigner.xAxis(250).yAxis(60).zoom(-90).signatureFieldName("signature");

        PDVisibleSigProperties signatureProperties = new PDVisibleSigProperties();
        signatureProperties.signerName(name).signerLocation(location)
                .signatureReason(reason).preferredSize(0).page(1)
                .visualSignEnabled(true).setPdVisibleSignature(signatureDesigner)
                .buildSignature();

        SignatureOptions options = new SignatureOptions();
        options.setVisualSignature(signatureProperties);

        document.addSignature(signature, dataSigner, options);

        /* Sign */
        document.saveIncremental(tempIn, tempOut);
        document.close();
        tempIn.close();

        /* Copy temporary file to an output stream */
        tempIn = new FileInputStream(temp2);
        copyStream(tempIn, signedPdf);
    } catch (IOException e) {
        logger.error("PDF signing failure", e);
    } catch (COSVisitorException e) {
        logger.error("PDF creation failure", e);
    } catch (SignatureException e) {
        logger.error("PDF signing failure", e);
    } finally {
        closeStream(originalPdf);
        closeStream(signedPdf);
        closeStream(randomAccessFile);
        closeStream(tempOut);
        deleteTempFile(temp);
        deleteTempFile(temp2);
        deleteTempFile(scratchFile);
    }
}

private void deleteTempFile(File tempFile) {
    if (tempFile != null && tempFile.exists() && !tempFile.delete()) {
        tempFile.deleteOnExit();
    }
}

private void closeStream(Closeable is) {
    if (is!= null) {
        try {
            is.close();
        } catch (IOException e) {
            logger.error("failure", e);
        }
    }
}

private void copyStream(InputStream is, OutputStream os) throws IOException {
    byte[] buffer = new byte[1024];
    int c;
    while ((c = is.read(buffer)) != -1) {
        os.write(buffer, 0, c);
    }
    is.close();
}

Apart from file madness I don't see any text on the signature. This is how result looks like:

and this is how it looks, when I do similar thing with itext library

Why name, location and reason missing from the visual signature representation? How can I fix that?

Answer 1

Why name, location and reason missing from the visual signature representation?

They are not there because they are not drawn.

The default way of iText to represent a visualized signature is by adding those information to the visualization.

The default way of PDFBox' PDVisibleSigBuilder to represent a visualized signature is without such information.

Neither is wrong or right, both merely are defaults.

The canonical place where people shall look for such information is the signature panel after all.

How can I fix that?

The actual contents of the signature visualization are created by a PDVisibleSigBuilder instance during signatureProperties.buildSignature():

public void buildSignature() throws IOException
{
    PDFTemplateBuilder builder = new PDVisibleSigBuilder();
    PDFTemplateCreator creator = new PDFTemplateCreator(builder);
    setVisibleSignature(creator.buildPDF(getPdVisibleSignature()));
}

Thus, by replacing

    signatureProperties.signerName(name).signerLocation(location)
            .signatureReason(reason).preferredSize(0).page(1)
            .visualSignEnabled(true).setPdVisibleSignature(signatureDesigner)
            .buildSignature();

in your code by

    signatureProperties.signerName(name).signerLocation(location)
            .signatureReason(reason).preferredSize(0).page(1)
            .visualSignEnabled(true).setPdVisibleSignature(signatureDesigner);

    PDFTemplateBuilder builder = new ExtSigBuilder();
    PDFTemplateCreator creator = new PDFTemplateCreator(builder);
    signatureProperties.setVisibleSignature(creator.buildPDF(signatureProperties.getPdVisibleSignature()));

for a customized version ExtSigBuilder of this PDVisibleSigBuilder class, you can draw anything you want there, e.g.:

class ExtSigBuilder extends PDVisibleSigBuilder
{
    String fontName;

    public void createImageForm(PDResources imageFormResources, PDResources innerFormResource,
            PDStream imageFormStream, PDRectangle formrect, AffineTransform affineTransform, PDJpeg img)
            throws IOException
    {
        super.createImageForm(imageFormResources, innerFormResource, imageFormStream, formrect, affineTransform, img);

        PDFont font = PDType1Font.HELVETICA;
        fontName = getStructure().getImageForm().getResources().addFont(font);

        logger.info("Added font to image form: " + fontName);
    }

    public void injectAppearanceStreams(PDStream holderFormStream, PDStream innterFormStream, PDStream imageFormStream,
            String imageObjectName, String imageName, String innerFormName, PDVisibleSignDesigner properties)
            throws IOException
    {
        super.injectAppearanceStreams(holderFormStream, innterFormStream, imageFormStream, imageObjectName, imageName, innerFormName, properties);

        String imgFormComment = "q " + 100 + " 0 0 50 0 0 cm /" + imageName + " Do Q\n";
        String text = "BT /" + fontName + " 10 Tf (Hello) Tj ET\n";
        appendRawCommands(getStructure().getImageFormStream().createOutputStream(), imgFormComment + text);

        logger.info("Added text commands to image form: " + text);
    }
}

writes "Hello" in Helvetica at size 10 atop the lower left of the image form (the form actually displaying something).

PS: In my opinion the object oriented structure behind this should be completely overhauled.

Answer 2

Display the text over the signatory some time it doesn't look nice. For me, I create new image base on the text that I want to display. And merge it with the signatory image. I can add background for signatory image (company name watermark)

Here is the code create new signatory image with text and background:

public class ImageSignatory {

public static void main(String[] args) {
    DateFormat df = new SimpleDateFormat("MM.dd.yyyy");
    Date today = Calendar.getInstance().getTime();
    String reportDate = df.format(today);
    String text = "Signature eletronic Company AA DUC NGUYEN  - Date " + reportDate;
    String background = "background.png";
    String signImage = "sign.jpg";
    String textImage = createImageFromText(text);
    String imageResultURL = null ;
    try {

        String mergedImage = mergeTwoImage(signImage, textImage);
        imageResultURL = addBackgroundToImage(background, mergedImage);
    } catch (Exception ex) {

    }

}

public static String StringDivider(String s) {

    StringBuilder sb = new StringBuilder(s);
    int i = 0;
    while ((i = sb.indexOf(" ", i + 30)) != -1) {
        sb.replace(i, i + 1, "\n");
    }
    return sb.toString();

}

public static BufferedImage toBufferedImage(Image img) {
    if (img instanceof BufferedImage) {
        return (BufferedImage) img;
    }
    BufferedImage bimage = new BufferedImage(img.getWidth(null), img.getHeight(null), BufferedImage.TYPE_INT_ARGB);
    Graphics2D bGr = bimage.createGraphics();
    bGr.drawImage(img, 0, 0, null);
    bGr.dispose();
    return bimage;
}

public static String addBackgroundToImage(String backgroundPATH, String imagePath) {
    try {
        String imageResult = "result.jpg";
        Image backgroundImage = ImageIO.read(new File(backgroundPATH));
        int width = backgroundImage.getWidth(null);
        int height = backgroundImage.getHeight(null);

        Image signAndText = ImageIO.read(new File(imagePath));
        signAndText = signAndText.getScaledInstance(width, height, Image.SCALE_SMOOTH);
        signAndText = toBufferedImage(signAndText);

        BufferedImage combined = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics g2 = combined.getGraphics();
        g2.drawImage(backgroundImage, 0, 0, null);
        g2.drawImage(signAndText, 0, 0, null);
        g2.dispose();
        ImageIO.write(combined, "JPG", new File(imageResult));
        return imageResult;
    } catch (IOException ex) {
        return null;
    }
}

public static String mergeTwoImage(String first, String second) {
    try {
        String tempFileName = "merged_image.png";
        Image signatoryImage = ImageIO.read(new File(first));
        Image addtionalTextImage = ImageIO.read(new File(second));
        float ratio = (float) signatoryImage.getWidth(null) / (float) addtionalTextImage.getWidth(null);
        addtionalTextImage = addtionalTextImage.getScaledInstance((int) (ratio * (float) addtionalTextImage.getWidth(null)), (int) (ratio * (float) addtionalTextImage.getHeight(null)), Image.SCALE_SMOOTH);
        addtionalTextImage = toBufferedImage(addtionalTextImage);
        BufferedImage combinedTemp = new BufferedImage(signatoryImage.getWidth(null), signatoryImage.getHeight(null) + (int) (ratio * (float) addtionalTextImage.getHeight(null)), BufferedImage.TYPE_INT_ARGB);

        Graphics g = combinedTemp.getGraphics();
        g.drawImage(signatoryImage, 0, 0, null);
        g.drawImage(addtionalTextImage, 0, signatoryImage.getHeight(null), null);
        g.dispose();
        ImageIO.write(combinedTemp, "PNG", new File(tempFileName));
        return tempFileName;
    } catch (IOException ex) {
        return null;
    }
}

public static String createImageFromText(String text) {
    String tempFileName = "text.png";
    text = StringDivider(text);
    String[] textParts = text.split("\n");

    BufferedImage img = new BufferedImage(1, 1, BufferedImage.TYPE_INT_ARGB);
    Graphics2D g2d = img.createGraphics();
    Font font = new Font("Arial", Font.PLAIN, 48);
    g2d.setFont(font);
    FontMetrics fm = g2d.getFontMetrics();
    int width = 0;
    for (String textPart : textParts) {
        int tempWidth = fm.stringWidth(textPart);
        if (tempWidth > width) {
            width = tempWidth;
        }
    }
    width += 10;
    int oneLineHeight = fm.getHeight();
    int height = (oneLineHeight) * textParts.length;
    g2d.dispose();

    img = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
    g2d = img.createGraphics();
    g2d.setRenderingHint(RenderingHints.KEY_ALPHA_INTERPOLATION, RenderingHints.VALUE_ALPHA_INTERPOLATION_QUALITY);
    g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
    g2d.setRenderingHint(RenderingHints.KEY_COLOR_RENDERING, RenderingHints.VALUE_COLOR_RENDER_QUALITY);
    g2d.setRenderingHint(RenderingHints.KEY_DITHERING, RenderingHints.VALUE_DITHER_ENABLE);
    g2d.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON);
    g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
    g2d.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
    g2d.setRenderingHint(RenderingHints.KEY_STROKE_CONTROL, RenderingHints.VALUE_STROKE_PURE);
    g2d.setFont(font);
    fm = g2d.getFontMetrics();
    g2d.setColor(Color.BLACK);
    int index = 0;
    for (String textPart : textParts) {
        g2d.drawString(textPart, 5, (oneLineHeight) * index + fm.getAscent());
        index++;
    }

    g2d.dispose();
    try {
        ImageIO.write(img, "PNG", new File(tempFileName));
    } catch (IOException ex) {
        return null;
    }
    return tempFileName;
}

 public static void removeFile(String fileName) {
    try {
        File file = new File(fileName);
        file.delete();
    } catch (Exception ex) {

    }
}

}