fix(sigblock): invalid preview in case of sig-blocks with more than half page height

Issue: #68

## Info:
This is only a work-around, because it looks like a general issue in methods to create visual signature tables.
T

1 files changed, 8 insertions, 7 deletions

diff --git a/pdf-as-pdfbox-2/src/main/java/at/gv/egiz/pdfas/lib/impl/signing/pdfbox2/PADESPDFBOXSigner.java b/pdf-as-pdfbox-2/src/main/java/at/gv/egiz/pdfas/lib/impl/signing/pdfbox2/PADESPDFBOXSigner.java
index ef1f14b2..42f16598 100644
--- a/pdf-as-pdfbox-2/src/main/java/at/gv/egiz/pdfas/lib/impl/signing/pdfbox2/PADESPDFBOXSigner.java
+++ b/pdf-as-pdfbox-2/src/main/java/at/gv/egiz/pdfas/lib/impl/signing/pdfbox2/PADESPDFBOXSigner.java
@@ -363,7 +363,7 @@ public class PADESPDFBOXSigner implements IPdfSigner, IConfigurationConstants {
         }
 
         properties = new PDFAsVisualSignatureProperties(pdfObject.getStatus().getSettings(), pdfObject,
-            (PdfBoxVisualObject) visualObject, positioningInstruction, signatureProfileSettings);
+            (PdfBoxVisualObject) visualObject, positioningInstruction, signatureProfileSettings, false);
 
         properties.buildSignature();
 
@@ -825,7 +825,7 @@ public class PADESPDFBOXSigner implements IPdfSigner, IConfigurationConstants {
         positioningInstruction = Positioning.determineTablePositioning(new TablePos(), "", origDoc,
             visualObject, pdfObject.getStatus().getSettings());
       }
-
+          
       origDoc.close();
 
       final SignaturePositionImpl position = new SignaturePositionImpl();
@@ -839,15 +839,16 @@ public class PADESPDFBOXSigner implements IPdfSigner, IConfigurationConstants {
 
       final PDFAsVisualSignatureProperties properties = new PDFAsVisualSignatureProperties(
           pdfObject.getStatus().getSettings(), pdfObject, (PdfBoxVisualObject) visualObject,
-          positioningInstruction, signatureProfileSettings);
-
+          positioningInstruction, signatureProfileSettings, true);
+      
+      // build visual-signature form
       properties.buildSignature();
-      PDDocument visualDoc;
+            
+      PDDocument visualDoc;     
       synchronized (PDDocument.class) {
         visualDoc = PDDocument.load(properties.getVisibleSignature());
       }
 
-
       final float stdRes = 72;
       final float targetRes = resolution;
       final float factor = targetRes / stdRes;
@@ -859,7 +860,7 @@ public class PADESPDFBOXSigner implements IPdfSigner, IConfigurationConstants {
 
       visualDoc.close();
       pdfRenderer = null;
-      
+            
       final BufferedImage cutOut = new BufferedImage(
           (int) (position.getWidth() * factor),
           (int) (position.getHeight() * factor),