iTextPDF签名：如何不显示签名字段，但显示图像

Question

我使用itextpdf-5在PDF上签名。我想在文档上签名，但要使除图像之外的所有字段（原因，位置）不可见。我可以在第三方程序中执行此操作（我附有此类PDF的示例：签名存储所有数据，但不显示）。我在程序中未找到可在程序中找到的类似文件（我将包含示例代码）

Example PDF with hide data

 private static void emptySignature(String src, String dest, String sigName, int page, int x, int y) {
    try {
        Image image = Image.getInstance(new File(currentPatient.getCurrentSign().getLocalFilePath()).toURL());;
        PdfReader reader = new PdfReader(src);
        FileOutputStream os = new FileOutputStream(dest);
        PdfStamper stamper = PdfStamper.createSignature(reader,os,'\0',new File("data/results/temp"),true);

        PdfSignatureAppearance appearance = stamper.getSignatureAppearance();
        appearance.setVisibleSignature(new Rectangle(x,y,x+80,y-60),page,sigName); 
        //Hide it!
        appearance.setReason("Nikita");
        appearance.setLocation("Sanitas");
        //No hide
        appearance.setImage(image);

        ExternalSignatureContainer external = new ExternalBlankSignatureContainer(PdfName.ADOBE_PPKLITE, PdfName.ADBE_PKCS7_DETACHED);
        MakeSignature.signExternalContainer(appearance,external,8192);
        os.close();
        reader.close();
        stamper.close();
    } catch (Exception ex) {}
}

Answer 1

PdfSignatureAppearance具有带有setRenderingMode参数的设置器RenderingMode。RenderingMode是具有以下值的枚举：

public enum RenderingMode {
    /**
     * The rendering mode is just the description.
     */
    DESCRIPTION,
    /**
     * The rendering mode is the name of the signer and the description.
     */
    NAME_AND_DESCRIPTION,
    /**
     * The rendering mode is an image and the description.
     */
    GRAPHIC_AND_DESCRIPTION,
    /**
     * The rendering mode is just an image.
     */
    GRAPHIC
}

要使除图像以外的所有字段（原因，位置）不可见，因此，只需将渲染模式设置为GRAPHIC：

appearance.setRenderingMode(RenderingMode.GRAPHIC);