PDFBOX-5938: implement missing method and use it

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1923313 13f79535-47bb-0310-9956-ffa450edef68

Author: THausherr

pdfbox/src/main/java/org/apache/pdfbox/pdmodel/graphics/form/PDFormXObject.java

@@ -121,9 +121,9 @@ public void setFormType(int formType)
     }
 
     /**
-     * Returns the group attributes dictionary.
+     * Returns the transparency group attributes dictionary.
      *
-     * @return the group attributes dictionary
+     * @return the transparency group attributes dictionary, never null.
      */
     public PDTransparencyGroupAttributes getGroup()
     {
@@ -137,7 +137,18 @@ public PDTransparencyGroupAttributes getGroup()
         }
         return group;
     }
-    
+
+    /**
+     * Sets the transparency group attributes dictionary.
+     *
+     * @param group a transparency group attributes dictionary.
+     */
+    public void setGroup(PDTransparencyGroupAttributes group)
+    {
+        this.group = group;
+        getCOSObject().setItem(COSName.GROUP, group);
+    }
+
     public PDStream getContentStream()
     {
         return new PDStream(getCOSObject());

pdfbox/src/main/java/org/apache/pdfbox/pdmodel/interactive/annotation/handlers/PDHighlightAppearanceHandler.java

@@ -19,8 +19,6 @@
 import java.io.IOException;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.LogManager;
-import org.apache.pdfbox.cos.COSDictionary;
-import org.apache.pdfbox.cos.COSName;
 import org.apache.pdfbox.pdmodel.PDFormContentStream;
 import org.apache.pdfbox.pdmodel.PDResources;
 import org.apache.pdfbox.pdmodel.common.PDRectangle;
@@ -32,6 +30,7 @@
 import org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotationHighlight;
 import org.apache.pdfbox.pdmodel.PDAppearanceContentStream;
 import org.apache.pdfbox.pdmodel.PDDocument;
+import org.apache.pdfbox.pdmodel.graphics.form.PDTransparencyGroupAttributes;
 
 /**
  * 
@@ -128,10 +127,7 @@ public void generateNormalAppearance()
                 mwfofrmCS.drawForm(frm2);
             }
             frm1.setBBox(annotation.getRectangle());
-            COSDictionary groupDict = new COSDictionary();
-            groupDict.setItem(COSName.S, COSName.TRANSPARENCY);
-            //TODO PDFormXObject.setGroup() is missing
-            frm1.getCOSObject().setItem(COSName.GROUP, groupDict);
+            frm1.setGroup(new PDTransparencyGroupAttributes());
             cs.drawForm(frm1);
             frm2.setBBox(annotation.getRectangle());
             try (PDFormContentStream frm2CS = new PDFormContentStream(frm2))