Fix issue with setters from PdfSignatureFormField

DEVSIX-7969

Author: AnhelinaM

sign/src/main/java/com/itextpdf/signatures/PdfSignatureAppearance.java

@@ -188,6 +188,9 @@ public class PdfSignatureAppearance {
      * Indicates if we need to reuse the existing appearance as layer 0.
      */
     private boolean reuseAppearance = false;
+    // Option for backward compatibility.
+    private boolean reuseAppearanceSet = false;
+
 
     /**
      * Creates a PdfSignatureAppearance.
@@ -546,6 +549,7 @@ public PdfSignatureAppearance setSignatureGraphic(ImageData signatureGraphic) {
     @Deprecated
     public PdfSignatureAppearance setReuseAppearance(boolean reuseAppearance) {
         this.reuseAppearance = reuseAppearance;
+        this.reuseAppearanceSet = true;
         return this;
     }
 
@@ -868,6 +872,16 @@ boolean isReuseAppearance() {
         return reuseAppearance;
     }
 
+    /**
+     * Checks if reuseAppearance value was set using {@link this#setReuseAppearance(boolean)}.
+     * Used for backward compatibility.
+     *
+     * @return boolean value.
+     */
+    boolean isReuseAppearanceSet() {
+        return reuseAppearanceSet;
+    }
+
     /**
      * Gets the background layer that is present when creating the signature field if it was set.
      *

sign/src/main/java/com/itextpdf/signatures/PdfSigner.java

@@ -208,6 +208,11 @@ public enum CryptoStandard {
      */
     protected boolean closed = false;
 
+    /**
+     * AcroForm for the PdfDocument.
+     */
+    private final PdfAcroForm acroForm;
+
     /**
      * Creates a PdfSigner instance. Uses a {@link java.io.ByteArrayOutputStream} instead of a temporary file.
      *
@@ -241,6 +246,7 @@ public PdfSigner(PdfReader reader, OutputStream outputStream, String path, Stamp
             this.tempFile = FileUtil.createTempFile(path);
             document = initDocument(reader, new PdfWriter(FileUtil.getFileOutputStream(tempFile)), localProps);
         }
+        acroForm = PdfFormCreator.getAcroForm(document, true);
 
         originalOS = outputStream;
         fieldName = getNewSigFieldName();
@@ -255,6 +261,7 @@ public PdfSigner(PdfReader reader, OutputStream outputStream, String path, Stamp
             this.tempFile = tempFile;
         }
         this.document = document;
+        this.acroForm = PdfFormCreator.getAcroForm(document, true);
         this.originalOS = outputStream;
         this.fieldName = getNewSigFieldName();
         this.appearance = new PdfSignatureAppearance(document, new Rectangle(0, 0), 1);
@@ -385,7 +392,6 @@ public void setSignatureEvent(ISignatureEvent signatureEvent) {
      * @return A new signature field name.
      */
     public String getNewSigFieldName() {
-        PdfAcroForm acroForm = PdfFormCreator.getAcroForm(document, true);
         String name = "Signature";
         int step = 1;
 
@@ -404,8 +410,6 @@ public String getNewSigFieldName() {
      */
     public void setFieldName(String fieldName) {
         if (fieldName != null) {
-            PdfAcroForm acroForm = PdfFormCreator.getAcroForm(document, true);
-
             PdfFormField field = acroForm.getField(fieldName);
             if (field != null) {
                 if (!PdfName.Sig.equals(field.getFormType())) {
@@ -431,7 +435,7 @@ public void setFieldName(String fieldName) {
                 }
             }
 
-            appearance.setFieldName(fieldName);
+            this.appearance.setFieldName(fieldName);
             this.fieldName = fieldName;
         }
     }
@@ -622,6 +626,31 @@ public PdfSigner setLocation(String location) {
         return this;
     }
 
+    /**
+     * Gets the signature field to be signed. The field can already be presented in the document. If the field is
+     * not presented in the document, it will be created.
+     *
+     * <p>
+     * This field instance is expected to be used for setting appearance related properties such as
+     * {@link PdfSignatureFormField#setReuseAppearance}, {@link PdfSignatureFormField#setBackgroundLayer} and
+     * {@link PdfSignatureFormField#setSignatureAppearanceLayer}.
+     *
+     * @return the {@link PdfSignatureFormField} instance.
+     */
+    public PdfSignatureFormField getSignatureField() {
+        PdfFormField field = acroForm.getField(fieldName);
+        if (field == null) {
+            PdfSignatureFormField sigField = new SignatureFormFieldBuilder(document, fieldName)
+                    .setWidgetRectangle(getPageRect()).createSignature();
+            acroForm.addField(sigField);
+            return sigField;
+        }
+        if (field instanceof PdfSignatureFormField) {
+            return (PdfSignatureFormField) field;
+        }
+        return null;
+    }
+
     /**
      * Signs the document using the detached mode, CMS or CAdES equivalent.
      * <br><br>
@@ -1036,7 +1065,6 @@ protected void preClose(Map<PdfName, Integer> exclusionSizes) throws IOException
             throw new PdfException(SignExceptionMessageConstant.DOCUMENT_ALREADY_PRE_CLOSED);
         }
         preClosed = true;
-        PdfAcroForm acroForm = PdfFormCreator.getAcroForm(document, true);
         SignatureUtil sgnUtil = new SignatureUtil(document);
         String name = getFieldName();
         boolean fieldExist = sgnUtil.doesSignatureFieldExist(name);
@@ -1149,7 +1177,6 @@ protected void preClose(Map<PdfName, Integer> exclusionSizes) throws IOException
      */
     protected PdfSigFieldLock populateExistingSignatureFormField(PdfAcroForm acroForm) throws IOException {
         PdfSignatureFormField sigField = (PdfSignatureFormField) acroForm.getField(fieldName);
-        sigField.put(PdfName.V, cryptoDictionary.getPdfObject());
 
         PdfSigFieldLock sigFieldLock = sigField.getSigFieldLockDictionary();
 
@@ -1172,9 +1199,15 @@ protected PdfSigFieldLock populateExistingSignatureFormField(PdfAcroForm acroFor
         sigField.put(PdfName.F, new PdfNumber(flags));
 
         sigField.disableFieldRegeneration();
-        sigField.setReuseAppearance(appearance.isReuseAppearance())
-                .setSignatureAppearanceLayer(appearance.getSignatureAppearanceLayer())
-                .setBackgroundLayer(appearance.getBackgroundLayer());
+        if (appearance.isReuseAppearanceSet()) {
+            sigField.setReuseAppearance(appearance.isReuseAppearance());
+        }
+        if (appearance.getSignatureAppearanceLayer() != null) {
+            sigField.setSignatureAppearanceLayer(appearance.getSignatureAppearanceLayer());
+        }
+        if (appearance.getBackgroundLayer() != null) {
+            sigField.setBackgroundLayer(appearance.getBackgroundLayer());
+        }
         sigField.getFirstFormAnnotation().setFormFieldElement(appearance.getSignatureAppearance());
         sigField.enableFieldRegeneration();
 
@@ -1382,24 +1415,21 @@ protected boolean documentContainsCertificationOrApprovalSignatures() {
             urSignature = catalogPerms.getAsDictionary(PdfName.UR3);
         }
 
-        PdfAcroForm acroForm = PdfFormCreator.getAcroForm(document, false);
-        if (acroForm != null) {
-            for (Map.Entry<String, PdfFormField> entry : acroForm.getAllFormFields().entrySet()) {
-                PdfDictionary fieldDict = entry.getValue().getPdfObject();
-                if (!PdfName.Sig.equals(fieldDict.get(PdfName.FT)))
-                    continue;
-                PdfDictionary sigDict = fieldDict.getAsDictionary(PdfName.V);
-                if (sigDict == null)
-                    continue;
-                PdfSignature pdfSignature = new PdfSignature(sigDict);
-                if (pdfSignature.getContents() == null || pdfSignature.getByteRange() == null) {
-                    continue;
-                }
+        for (Map.Entry<String, PdfFormField> entry : acroForm.getAllFormFields().entrySet()) {
+            PdfDictionary fieldDict = entry.getValue().getPdfObject();
+            if (!PdfName.Sig.equals(fieldDict.get(PdfName.FT)))
+                continue;
+            PdfDictionary sigDict = fieldDict.getAsDictionary(PdfName.V);
+            if (sigDict == null)
+                continue;
+            PdfSignature pdfSignature = new PdfSignature(sigDict);
+            if (pdfSignature.getContents() == null || pdfSignature.getByteRange() == null) {
+                continue;
+            }
 
-                if (!pdfSignature.getType().equals(PdfName.DocTimeStamp) && sigDict != urSignature) {
-                    containsCertificationOrApprovalSignature = true;
-                    break;
-                }
+            if (!pdfSignature.getType().equals(PdfName.DocTimeStamp) && sigDict != urSignature) {
+                containsCertificationOrApprovalSignature = true;
+                break;
             }
         }
         return containsCertificationOrApprovalSignature;

sign/src/test/java/com/itextpdf/signatures/sign/PdfSignatureAppearanceTest.java

@@ -30,6 +30,7 @@ This file is part of the iText (R) project.
 import com.itextpdf.forms.fields.PdfFormCreator;
 import com.itextpdf.forms.fields.PdfSignatureFormField;
 import com.itextpdf.forms.fields.SignatureFormFieldBuilder;
+import com.itextpdf.forms.form.element.SignatureFieldAppearance;
 import com.itextpdf.io.image.ImageDataFactory;
 import com.itextpdf.commons.utils.MessageFormatUtil;
 import com.itextpdf.kernel.colors.ColorConstants;
@@ -575,6 +576,47 @@ public void signExistedSignatureFieldTest() throws IOException, GeneralSecurityE
         compareSignatureAppearances(dest, SOURCE_FOLDER + "cmp_" + fileName);
     }
 
+    @Test
+    public void reuseAppearanceTest() throws GeneralSecurityException,
+            IOException, InterruptedException {
+        // Field is not merged with widget and has /P key
+        String src = SOURCE_FOLDER + "emptyFieldNotMerged.pdf";
+        String fileName = "reuseAppearance.pdf";
+        testReuseAppearance(src, fileName, false, true, false);
+    }
+
+    @Test
+    public void reuseAppearanceDeprecatedTest() throws GeneralSecurityException,
+            IOException, InterruptedException {
+        // Field is not merged with widget and has /P key
+        String src = SOURCE_FOLDER + "emptyFieldNotMerged.pdf";
+        String fileName = "reuseAppearanceDeprecated.pdf";
+        testReuseAppearance(src, fileName, true, false, true);
+    }
+
+    @Test
+    public void reuseAppearanceCompatibilityTest() throws GeneralSecurityException,
+            IOException, InterruptedException {
+        // Field is not merged with widget and has /P key
+        String src = SOURCE_FOLDER + "emptyFieldNotMerged.pdf";
+        String fileName = "reuseAppearanceCompatibility.pdf";
+        testReuseAppearance(src, fileName, true, true, false);
+    }
+
+    @Test
+    public void fieldLayersTest() throws IOException, GeneralSecurityException {
+        String src = SOURCE_FOLDER + "noSignatureField.pdf";
+        String fileName = "fieldLayersTest.pdf";
+        testLayers(src, fileName, false);
+    }
+
+    @Test
+    public void deprecatedLayersTest() throws IOException, GeneralSecurityException {
+        String src = SOURCE_FOLDER + "noSignatureField.pdf";
+        String fileName = "deprecatedLayersTest.pdf";
+        testLayers(src, fileName, true);
+    }
+
     private static void compareSignatureAppearances(String outPdf, String cmpPdf) throws IOException {
         ITextTest.printOutCmpPdfNameAndDir(outPdf, cmpPdf);
         try (PdfDocument outDoc = new PdfDocument(new PdfReader(outPdf))) {
@@ -590,6 +632,94 @@ private static void compareSignatureAppearances(String outPdf, String cmpPdf) th
         }
     }
 
+    private void testReuseAppearance(String src, String fileName, boolean useDeprecated, boolean fieldReuseAp,
+                                     boolean deprecatedReuseAp) throws IOException, GeneralSecurityException, InterruptedException {
+        String cmp = SOURCE_FOLDER + "cmp_" + fileName;
+        String dest = DESTINATION_FOLDER + fileName;
+        String fieldName = "Signature1";
+
+        PdfSigner signer = new PdfSigner(new PdfReader(src), new FileOutputStream(dest), new StampingProperties());
+        signer.setFieldName(fieldName);
+        signer.getSignatureField().setReuseAppearance(fieldReuseAp);
+        if (useDeprecated) {
+            signer.getSignatureAppearance().setReuseAppearance(deprecatedReuseAp);
+        }
+
+        signer.setReason("Test 1").setLocation("TestCity")
+                .setSignatureAppearance(new SignatureFieldAppearance(fieldName)
+                        .setContent("New appearance").setFontColor(ColorConstants.GREEN));
+
+        IExternalSignature pks = new PrivateKeySignature(pk, DigestAlgorithms.SHA256, FACTORY.getProviderName());
+        signer.signDetached(new BouncyCastleDigest(), pks, chain, null, null, null, 0, PdfSigner.CryptoStandard.CADES);
+
+        Assert.assertNull(new CompareTool().compareVisually(dest, cmp, DESTINATION_FOLDER, "diff_"));
+    }
+
+    private void testLayers(String src, String fileName, boolean useDeprecated)
+            throws IOException, GeneralSecurityException {
+        String dest = DESTINATION_FOLDER + fileName;
+        String fieldName = "Signature1";
+
+        PdfSigner signer = new PdfSigner(new PdfReader(src), new FileOutputStream(dest), new StampingProperties());
+        signer.setFieldName(fieldName);
+        signer.setPageRect(new Rectangle(250, 500, 100, 100)).setReason("Test 1").setLocation("TestCity")
+                .setSignatureAppearance(new SignatureFieldAppearance(fieldName));
+
+        PdfFormXObject layer0 = new PdfFormXObject(new Rectangle(0, 0, 100, 100));
+        // Draw pink rectangle with blue border
+        new PdfCanvas(layer0, signer.getDocument())
+                .saveState()
+                .setFillColor(ColorConstants.PINK)
+                .setStrokeColor(ColorConstants.BLUE)
+                .rectangle(0, 0, 100, 100)
+                .fillStroke()
+                .restoreState();
+
+        PdfFormXObject layer2 = new PdfFormXObject(new Rectangle(0, 0, 100, 100));
+        // Draw yellow circle with gray border
+        new PdfCanvas(layer2, signer.getDocument())
+                .saveState()
+                .setFillColor(ColorConstants.YELLOW)
+                .setStrokeColor(ColorConstants.DARK_GRAY)
+                .circle(50, 50, 50)
+                .fillStroke()
+                .restoreState();
+
+        signer.getSignatureField().setBackgroundLayer(layer0).setSignatureAppearanceLayer(layer2);
+
+        if (useDeprecated) {
+            // Creating the appearance
+            PdfSignatureAppearance appearance = signer.getSignatureAppearance();
+
+            PdfFormXObject deprecatedLayer0 = appearance.getLayer0();
+            // Draw yellow rectangle with gray border
+            new PdfCanvas(deprecatedLayer0, signer.getDocument())
+                    .saveState()
+                    .setFillColor(ColorConstants.YELLOW)
+                    .setStrokeColor(ColorConstants.DARK_GRAY)
+                    .rectangle(0, 0, 100, 100)
+                    .fillStroke()
+                    .restoreState();
+
+            PdfFormXObject deprecatedLayer2 = appearance.getLayer2();
+            // Draw pink circle with blue border
+            new PdfCanvas(deprecatedLayer2, signer.getDocument())
+                    .saveState()
+                    .setFillColor(ColorConstants.PINK)
+                    .setStrokeColor(ColorConstants.BLUE)
+                    .circle(50, 50, 50)
+                    .fillStroke()
+                    .restoreState();
+        }
+
+        // Signing
+        IExternalSignature pks = new PrivateKeySignature(pk, DigestAlgorithms.SHA256,
+                FACTORY.getProviderName());
+        signer.signDetached(new BouncyCastleDigest(), pks, chain, null, null, null, 0, PdfSigner.CryptoStandard.CADES);
+
+        compareSignatureAppearances(dest, SOURCE_FOLDER + "cmp_" + fileName);
+    }
+
     private void testSignatureOnRotatedPage(int pageNum, PdfSignatureAppearance.RenderingMode renderingMode,
             StringBuilder assertionResults) throws IOException, GeneralSecurityException, InterruptedException {
         String fileName = "signaturesOnRotatedPages" + pageNum + "_mode_" + renderingMode.name() + ".pdf";