tdf#160526, tdf#160549: fix split conditions at page start

A single large object in a paragraph must be moved down, when the page
has other content before this. On the other hand, there must not be
moving down, when an unsuccessful attempt to move was already done (so
the master frame is empty), or even the first time, when the frame is
at the page body start.

Change-Id: Ib8e2fe7b77c622d9cfac22722ca6b55dba7ad8ae
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/165869
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>

1 files changed, 88 insertions, 13 deletions

diff --git a/sw/source/core/text/frmform.cxx b/sw/source/core/text/frmform.cxx
index e19b834a5618..97eff3e607ec 100644
--- a/sw/source/core/text/frmform.cxx
+++ b/sw/source/core/text/frmform.cxx
@@ -1081,6 +1081,54 @@ void SwTextFrame::ChangeOffset( SwTextFrame* pFrame, TextFrameIndex nNew )
         MoveFlyInCnt( pFrame, nNew, TextFrameIndex(COMPLETE_STRING) );
 }
 
+static bool isFirstVisibleFrameInBody(const SwTextFrame* pFrame)
+{
+    const SwFrame* pBodyFrame = pFrame->FindBodyFrame();
+    if (!pBodyFrame)
+        return false;
+    for (const SwFrame* pCur = pFrame;;)
+    {
+        for (const SwFrame* pPrev = pCur->GetPrev(); pPrev; pPrev = pPrev->GetPrev())
+            if (!pPrev->IsHiddenNow())
+                return false;
+        pCur = pCur->GetUpper();
+        assert(pCur); // We found pBodyFrame, right?
+        if (pCur->IsBodyFrame())
+            return true;
+    }
+}
+
+static bool hasFly(const SwTextFrame* pFrame)
+{
+    if (auto pDrawObjs = pFrame->GetDrawObjs(); pDrawObjs && pDrawObjs->size())
+    {
+        auto anchorId = (*pDrawObjs)[0]->GetFrameFormat()->GetAnchor().GetAnchorId();
+        if (anchorId == RndStdIds::FLY_AT_PARA || anchorId == RndStdIds::FLY_AT_CHAR)
+            return true;
+    }
+    return false;
+}
+
+static bool hasAtPageFly(const SwFrame* pFrame)
+{
+    auto pPageFrame = pFrame->FindPageFrame();
+    if (!pPageFrame)
+        return false;
+    auto pPageDrawObjs = pPageFrame->GetDrawObjs();
+    if (pPageDrawObjs)
+    {
+        for (const auto pObject : *pPageDrawObjs)
+            if (pObject->GetFrameFormat()->GetAnchor().GetAnchorId() == RndStdIds::FLY_AT_PAGE)
+                return true;
+    }
+    return false;
+}
+
+static bool isReallyEmptyMaster(const SwTextFrame* pFrame)
+{
+    return pFrame->IsEmptyMaster() && (!pFrame->GetDrawObjs() || !pFrame->GetDrawObjs()->size());
+}
+
 void SwTextFrame::FormatAdjust( SwTextFormatter &rLine,
                              WidowsAndOrphans &rFrameBreak,
                              TextFrameIndex const nStrLen,
@@ -1108,27 +1156,55 @@ void SwTextFrame::FormatAdjust( SwTextFormatter &rLine,
                      ? 1 : 0;
 
     SwTextFormatInfo& rInf = rLine.GetInfo();
+    bool bEmptyWithSplitFly = false;
     if (nNew == 0 && !nStrLen && !rInf.GetTextFly().IsOn() && IsEmptyWithSplitFly())
     {
         // Empty paragraph, so IsBreakNow() is not called, but we should split the fly portion and
         // the paragraph marker.
         nNew = 1;
+        bEmptyWithSplitFly = true;
     }
 
+    const SwFrame *pBodyFrame = FindBodyFrame();
+
     // i#84870
     // no split of text frame, which only contains an as-character anchored object
-    bool bOnlyContainsAsCharAnchoredObj =
+    bool bLoneAsCharAnchoredObj =
+            pBodyFrame &&
             !IsFollow() && nStrLen == TextFrameIndex(1) &&
             GetDrawObjs() && GetDrawObjs()->size() == 1 &&
             (*GetDrawObjs())[0]->GetFrameFormat()->GetAnchor().GetAnchorId() == RndStdIds::FLY_AS_CHAR;
 
-    // Still try split text frame if we have columns.
-    if (FindColFrame())
-        bOnlyContainsAsCharAnchoredObj = false;
-
-    if ( nNew && bOnlyContainsAsCharAnchoredObj )
+    if (bLoneAsCharAnchoredObj)
     {
-        nNew = 0;
+        // Still try split text frame if we have columns.
+        if (FindColFrame())
+            bLoneAsCharAnchoredObj = false;
+        // tdf#160526: only no split if there is no preceding frames on same page
+        else if (!isFirstVisibleFrameInBody(this))
+            bLoneAsCharAnchoredObj = false;
+        else
+            nNew = 0;
+    }
+    else if (nNew)
+    {
+        if (IsFollow())
+        {
+            // tdf#160549: do not split the frame at the very beginning again, if its master was empty
+            auto precede = static_cast<SwTextFrame*>(GetPrecede());
+            assert(precede);
+            auto precedeText = precede->DynCastTextFrame();
+            assert(precedeText);
+            if (isReallyEmptyMaster(precedeText))
+                nNew = 0;
+        }
+        else if (!bEmptyWithSplitFly)
+        {
+            // Do not split immediately in the beginning of page (unless there is an at-para or
+            // at-char or at-page fly, which pushes the rest down)
+            if (isFirstVisibleFrameInBody(this) && !hasFly(this) && !hasAtPageFly(pBodyFrame))
+                nNew = 0;
+        }
     }
 
     if ( nNew )
@@ -1136,8 +1212,6 @@ void SwTextFrame::FormatAdjust( SwTextFormatter &rLine,
         SplitFrame( nEnd );
     }
 
-    const SwFrame *pBodyFrame = FindBodyFrame();
-
     const tools::Long nBodyHeight = pBodyFrame ? ( IsVertical() ?
                                           pBodyFrame->getFrameArea().Width() :
                                           pBodyFrame->getFrameArea().Height() ) : 0;
@@ -1239,9 +1313,10 @@ void SwTextFrame::FormatAdjust( SwTextFormatter &rLine,
             // content or contains no content, but has a numbering.
             // i#84870 - No split, if text frame only contains one
             // as-character anchored object.
-            if ( !bOnlyContainsAsCharAnchoredObj &&
-                 (nStrLen > TextFrameIndex(0) ||
-                   bHasVisibleNumRule )
+            if (!bLoneAsCharAnchoredObj
+                && (bHasVisibleNumRule
+                    || (nStrLen > TextFrameIndex(0)
+                        && (nEnd != rLine.GetStart() || rInf.GetRest())))
                )
             {
                 SplitFrame( nEnd );
@@ -1265,7 +1340,7 @@ void SwTextFrame::FormatAdjust( SwTextFormatter &rLine,
     SwTwips nChg = rLine.CalcBottomLine() - nDocPrtTop - nOldHeight;
 
     //#i84870# - no shrink of text frame, if it only contains one as-character anchored object.
-    if ( nChg < 0 && !bDelta && bOnlyContainsAsCharAnchoredObj )
+    if (nChg < 0 && !bDelta && bLoneAsCharAnchoredObj)
     {
         nChg = 0;
     }