Java 类com.itextpdf.text.pdf.AcroFields.Item 实例源码

private int numberOfVisibleSignatureFieldsOnSignaturePage(AcroFields readerFields, ArrayList<String> signatureFieldsNames, int signaturePage) {
    int count = 0;
    for (String signatureFieldName : signatureFieldsNames) {
        Item i = readerFields.getFieldItem(signatureFieldName);
        int page = i.getPage(0);
        if(page == signaturePage){
            PdfDictionary pdct = i.getMerged(0); 
            PdfNumber flags = pdct.getAsNumber(PdfName.F); 
            if ((flags.intValue() & PdfAnnotation.FLAGS_HIDDEN) == 0) {
                count = count + 1;
            } 
        }
    }
    return count;
}

/**
 * <a href="http://stackoverflow.com/questions/37027579/how-to-associate-a-previous-signature-in-a-new-signature-field">
 * How to associate a previous signature in a new signature field
 * </a>
 * <br/>
 * <span>BLANK-signed.pdf, <em>a blank file from elsewhere with an invisible signature.</em></span>
 * <p>
 * Quite surprisingly it turns out that changing the signature appearance is possible without
 * breaking the signature, merely a warning appears which can be hidden by simply signing again.
 * </p>
 */
@Test
public void testChangeAppearances() throws IOException, DocumentException
{
    try (   InputStream resource = getClass().getResourceAsStream("BLANK-signed.pdf");
            OutputStream result = new FileOutputStream(new File(RESULT_FOLDER, "BLANK-signed-app.pdf")))
    {
        PdfReader pdfReader = new PdfReader(resource);
        PdfStamper pdfStamper = new PdfStamper(pdfReader, result, '\0', true);

        AcroFields acroFields = pdfStamper.getAcroFields();
        for (String signatureName : acroFields.getSignatureNames())
        {
            Item field = acroFields.getFieldItem(signatureName);
            field.writeToAll(PdfName.RECT, new PdfArray(new int[]{100,100,200,200}), Item.WRITE_WIDGET);
            field.markUsed(acroFields, Item.WRITE_WIDGET);

            PdfAppearance appearance = PdfAppearance.createAppearance(pdfStamper.getWriter(), 100, 100);
            appearance.setColorStroke(BaseColor.RED);
            appearance.moveTo(0, 0);
            appearance.lineTo(99, 99);
            appearance.moveTo(0, 99);
            appearance.lineTo(99, 0);
            appearance.stroke();

            PdfDictionary appDict = new PdfDictionary();
            appDict.put(PdfName.N, appearance.getIndirectReference());
            field.writeToAll(PdfName.AP, appDict, Item.WRITE_WIDGET);
        }

        pdfStamper.close();
    }
}

/**
 * When the "signable" aspect is applied, extract the signature fields and add them
 * to the multivalue property
 */
public void onAddAspect(NodeRef nodeRef, QName aspectTypeQName) 
{
    try 
    {
        // when the aspect is added, extract the signature fields from the PDF
        ArrayList<String> signatureFields = new ArrayList<String>();
        ContentReader pdfReader = serviceRegistry.getContentService().getReader(nodeRef, ContentModel.PROP_CONTENT);
        PdfReader reader = new PdfReader(pdfReader.getContentInputStream());
        AcroFields form = reader.getAcroFields();
        Map<String, Item> fields = form.getFields();
        Iterator<String> it = fields.keySet().iterator();
        while(it.hasNext())
        {
            String fieldName = it.next();
            if(form.getFieldType(fieldName) == AcroFields.FIELD_TYPE_SIGNATURE)
            {
                // add this signature field to the list of available fields
                signatureFields.add(fieldName);
            }
        }
        serviceRegistry.getNodeService().setProperty(nodeRef, CounterSignSignatureModel.PROP_SIGNATUREFIELDS, signatureFields);

    }
    catch(IOException ex)
    {
        logger.error("Error extracting PDF signature fields from document: " + ex);
    }
}