java使用pdfbox添加带签名的图片

Question

我尝试了示例：CreateVisualSignature2.java，但没有成功。为什么我的图片不能显示，但是可以点击显示图片的区域，点击后也可以显示图片信息，但是看不到图片。

PDDocument doc = new PDDocument();
PDPage page = new PDPage(srcDoc.getPage(pageNum).getMediaBox());
doc.addPage(page);

PDAcroForm acroForm = new PDAcroForm(doc);
doc.getDocumentCatalog().setAcroForm(acroForm);

PDSignatureField signatureField = new PDSignatureField(acroForm);
PDAnnotationWidget widget = signatureField.getWidgets().get(0);
signatureField.setValue(signature);

List<PDField> acroFormFields = acroForm.getFields();
acroForm.setSignaturesExist(true);
acroForm.setAppendOnly(true);
acroForm.getCOSObject().setDirect(true);
acroFormFields.add(signatureField);

widget.setRectangle(rect);
widget.setPage(page);
page.getAnnotations().add(widget);
PDFormXObject form = new PDFormXObject(doc);
PDResources res = new PDResources();
PDRectangle bbox = new PDRectangle(rect.getWidth(), rect.getHeight());
form.setResources(res);
form.setFormType(1);
form.setBBox(bbox);

COSArray procSet = new COSArray();
procSet.add(COSName.getPDFName("PDF"));
procSet.add(COSName.getPDFName("Text"));
procSet.add(COSName.getPDFName("ImageB"));
procSet.add(COSName.getPDFName("ImageC"));
procSet.add(COSName.getPDFName("ImageI"));
res.getCOSObject().setItem(COSName.PROC_SET,procSet);

PDFormXObject frm = new PDFormXObject(doc);
PDResources res1 = new PDResources();
res.put(COSName.getPDFName("FRM"),frm);

frm.setResources(res1);
frm.setFormType(1);
frm.setBBox(bbox);

PDExtendedGraphicsState extGState = new PDExtendedGraphicsState();
extGState.setAlphaSourceFlag(false);
extGState.setBlendMode(BlendMode.DARKEN);
extGState.setNonStrokingAlphaConstant(1.0f);
extGState.setStrokingOverprintControl(true);
res1.put(COSName.getPDFName("Ext"),extGState);
res1.getCOSObject().setItem(COSName.PROC_SET,procSet);

ByteArrayOutputStream bao = new ByteArrayOutputStream();
ImageIO.write(image,"png", bao);
bao.flush();
byte[] imageByte = bao.toByteArray();
bao.close();

PDImageXObject ximage = PDImageXObject.createFromByteArray(doc, imageByte, null);
COSDictionary images = new COSDictionary();
images.setItem("Sign0",ximage);
res1.getCOSObject().setItem(COSName.XOBJECT,images);

PDAppearanceDictionary appearance = new PDAppearanceDictionary();
appearance.getCOSObject().setDirect(true);
PDAppearanceStream appearanceStream = new PDAppearanceStream(form.getCOSObject());
appearance.setNormalAppearance(appearanceStream);
widget.setAppearance(appearance);

PDAppearanceStream pdAppearanceStream = new PDAppearanceStream(frm.getCOSObject());
PDPageContentStream contentStream = new PDPageContentStream(doc, pdAppearanceStream);

contentStream.drawImage(ximage,0, 0,rect.getWidth(),rect.getHeight());

contentStream.close();

ByteArrayOutputStream baos = new ByteArrayOutputStream();

doc.save(baos);
doc.close();
return new ByteArrayInputStream(baos.toByteArray()

Answer 1

添加代码：

PDAppearanceStream pdStream = new PDAppearanceStream(form.getCOSObject());         
PDPageContentStream cStream = new PDPageContentStream(doc, pdStream);         
cStream.drawForm(frm);         
cStream.close();

非常感谢蒂尔曼·豪舍尔。