sw_redlinehide: SwTextFrame::IsHiddenNow() needs some work

Iterating the fields here looks a bit expensive, maybe it would be
better to check the ViewOptions first...

Change-Id: I41830e89a4fd683eee35bd2b0901fb9fb121b51c

sw/source/core/text/txtfrm.cxx

@@ -75,6 +75,7 @@
 #include <numrule.hxx>
 #include <swtable.hxx>
 #include <fldupde.hxx>
+#include <docufld.hxx>
 #include <IGrammarContact.hxx>
 #include <calbck.hxx>
 #include <ftnidx.hxx>
@@ -990,10 +991,56 @@ bool SwTextFrame::IsHiddenNow() const
         return true;
     }
 
-    if ( const SwViewShell* pVsh = getRootFrame()->GetCurrShell() )
+    bool bHiddenCharsHidePara(false);
+    bool bHiddenParaField(false);
+    if (m_pMergedPara)
+    {
+        TextFrameIndex nHiddenStart(COMPLETE_STRING);
+        TextFrameIndex nHiddenEnd(0);
+        if (auto const pScriptInfo = GetScriptInfo())
+        {
+            pScriptInfo->GetBoundsOfHiddenRange(TextFrameIndex(0),
+                    nHiddenStart, nHiddenEnd);
+        }
+        else // ParaPortion is created in Format, but this is called earlier
+        {
+            SwScriptInfo aInfo;
+            aInfo.InitScriptInfo(*m_pMergedPara->pFirstNode, m_pMergedPara.get(), IsRightToLeft());
+            aInfo.GetBoundsOfHiddenRange(TextFrameIndex(0),
+                        nHiddenStart, nHiddenEnd);
+        }
+        if (TextFrameIndex(0) == nHiddenStart &&
+            TextFrameIndex(GetText().getLength()) <= nHiddenEnd)
+        {
+            bHiddenCharsHidePara = true;
+        }
+        sw::MergedAttrIter iter(*this);
+        SwTextNode const* pNode(nullptr);
+        for (SwTextAttr const* pHint = iter.NextAttr(&pNode); pHint; pHint = iter.NextAttr(&pNode))
+        {
+            if (pHint->Which() == RES_TXTATR_FIELD)
+            {
+                const SwFormatField& rField = pHint->GetFormatField();
+                if (pNode->FieldCanHidePara(rField.GetField()->GetTyp()->Which()))
+                {
+                    bHiddenParaField = pNode->FieldHidesPara(*rField.GetField());
+                    if (!bHiddenParaField)
+                    {
+                        break; // not hidden, see CalcHiddenParaField()
+                    }
+                }
+            }
+        }
+    }
+    else
+    {
+        bHiddenCharsHidePara = static_cast<SwTextNode const*>(SwFrame::GetDep())->HasHiddenCharAttribute( true );
+        bHiddenParaField = static_cast<SwTextNode const*>(SwFrame::GetDep())->IsHiddenByParaField();
+    }
+    const SwViewShell* pVsh = getRootFrame()->GetCurrShell();
+
+    if ( pVsh && ( bHiddenCharsHidePara || bHiddenParaField ) )
     {
-        const bool bHiddenCharsHidePara = GetTextNode()->HasHiddenCharAttribute(true);
-        const bool bHiddenParaField = GetTextNode()->IsHiddenByParaField();
 
         if (
              ( bHiddenParaField &&