Improve PdfSigner signature appearance customization API

DEVSIX-7795

Author: AnhelinaM

itext/itext.samples/itext/samples/sandbox/signatures/SignatureExample.cs

@@ -6,6 +6,7 @@
 using iText.Bouncycastle.Crypto;
 using iText.Commons.Bouncycastle.Cert;
 using iText.Commons.Bouncycastle.Crypto;
+using iText.Forms.Form.Element;
 using iText.IO.Image;
 using iText.Kernel.Geom;
 using iText.Kernel.Pdf;
@@ -57,14 +58,15 @@ protected void SignDocumentSignature(string filePath, ElectronicSignatureInfoDTO
             // If you create new signature field (or use SetFieldName(System.String) with
             // the name that doesn't exist in the document or don't specify it at all) then
             // the signature is invisible by default.
-            PdfSignatureAppearance signatureAppearance = pdfSigner.GetSignatureAppearance();
-            signatureAppearance.SetRenderingMode(PdfSignatureAppearance.RenderingMode.GRAPHIC);
-            signatureAppearance.SetReason("");
-            signatureAppearance.SetLocationCaption("");
-            signatureAppearance.SetSignatureGraphic(clientSignatureImage);
-            signatureAppearance.SetPageNumber(signatureInfo.PageNumber);
-            signatureAppearance.SetPageRect(new Rectangle(signatureInfo.Left, signatureInfo.Bottom,
-                25, 25));
+            SignatureFieldAppearance appearance = new SignatureFieldAppearance(pdfSigner.GetFieldName())
+                    .SetRenderingMode(SignatureFieldAppearance.RenderingMode.GRAPHIC)
+                    .SetReason("")
+                    .SetLocationCaption("")
+                    .SetSignatureGraphic(clientSignatureImage);
+            pdfSigner.SetPageNumber(signatureInfo.PageNumber)
+                    .SetPageRect(new Rectangle(signatureInfo.Left, signatureInfo.Bottom,
+                25, 25))
+                    .SetSignatureAppearance(appearance);
 
             char[] password = "testpass".ToCharArray();
             IExternalSignature pks = GetPrivateKeySignature(CERT_PATH, password);

itext/itext.samples/itext/samples/sandbox/typography/latin/LatinSignature.cs

@@ -5,6 +5,7 @@
 using iText.Bouncycastle.Crypto;
 using iText.Commons.Bouncycastle.Cert;
 using iText.Commons.Utils;
+using iText.Forms.Form.Element;
 using Org.BouncyCastle.Crypto;
 using Org.BouncyCastle.X509;
 using iText.IO.Font;
@@ -65,12 +66,13 @@ public virtual void CreatePDF(String dest)
             signer.SetFieldName("Field1");
 
             // Get Signature Appearance and set some of its properties
-            signer.GetSignatureAppearance()
-                    .SetPageRect(rect)
+            SignatureFieldAppearance appearance = new SignatureFieldAppearance(signer.GetFieldName())
                     .SetReason(line1)
                     .SetLocation(line2)
                     .SetReasonCaption(line3)
-                    .SetLayer2Font(font);
+                    .SetFont(font);
+            signer.SetPageRect(rect)
+                    .SetSignatureAppearance(appearance);
 
             IX509Certificate[] certificateWrappers = new IX509Certificate[signChain.Length];
             for (int i = 0; i < certificateWrappers.Length; ++i) {