tdf#160958: merge hidden section's follows; move first-on-page section back

Change-Id: I6bd6707089dcea58d5df4bef63aa769769d97ea9
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/168235
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>

1 files changed, 52 insertions, 0 deletions

diff --git a/sw/source/core/layout/sectfrm.cxx b/sw/source/core/layout/sectfrm.cxx
index 23b427c1507b..c92af1303fae 100644
--- a/sw/source/core/layout/sectfrm.cxx
+++ b/sw/source/core/layout/sectfrm.cxx
@@ -833,6 +833,42 @@ void SwSectionFrame::MakeAll(vcl::RenderContext* pRenderContext)
         setFramePrintAreaValid(true);
         return;
     }
+
+    if (!GetPrev() && !IsFollow() && IsInDocBody() && IsHiddenNow())
+    {
+        // This may be the first frame on a page, and it may had moved to that page because its
+        // content required that (a page break in the first paragraph, or a tall first line, or
+        // "do not break paragraph" setting, or the like). Try to move back, to allow following
+        // frames to move back, if possible. Sections cannot move back; workaround by a call to
+        // GetPrevSctLeaf(), which may return a candidate upper frame on a previous page, or it
+        // may create a new master for this at the end of the previous page. Cut and paste this
+        // appropriately; then drop the temporary, if needed.
+        if (SwLayoutFrame* moveBackPos = GetPrevSctLeaf())
+        {
+            SwLayoutFrame* newUpper = moveBackPos;
+            SwFrame* newSibling = nullptr;
+            const bool temporaryMasterCreated = IsFollow();
+            if (temporaryMasterCreated)
+            {
+                assert(moveBackPos == &GetPrecede()->GetFrame());
+                newUpper = moveBackPos->GetUpper();
+                newSibling = moveBackPos->GetNext(); // actually, will be also nullptr
+            }
+            if (newUpper != GetUpper())
+            {
+                // Can't use MoveSubTree, because the move needs to fire events to re-layout
+                Cut();
+                Paste(newUpper, newSibling);
+            }
+            if (temporaryMasterCreated)
+            {
+                moveBackPos->Cut();
+                DestroyFrame(moveBackPos);
+            }
+            assert(!IsFollow());
+        }
+    }
+
     LockJoin(); // I don't let myself to be destroyed on the way
 
     while( GetNext() && GetNext() == GetFollow() )
@@ -843,6 +879,17 @@ void SwSectionFrame::MakeAll(vcl::RenderContext* pRenderContext)
             break;
     }
 
+    if (GetFollow() && IsHiddenNow())
+    {
+        // Merge all the follows of this hidden section
+        while (auto* follow = GetFollow())
+        {
+            MergeNext(follow);
+            if (GetFollow() == follow) // failed to merge
+                break; // avoid endless loop
+        }
+    }
+
     // OD 2004-03-15 #116561# - In online layout join the follows, if section
     // can grow.
     const SwViewShell *pSh = getRootFrame()->GetCurrShell();
@@ -2677,6 +2724,11 @@ void SwSectionFrame::SwClientNotify(const SwModify& rMod, const SfxHint& rHint)
     {
         InvalidateAll();
         InvalidateObjs(false);
+        {
+            // Set it to a huge positive value, to make sure a recalculation fires
+            SwFrameAreaDefinition::FrameAreaWriteAccess area(*this);
+            SwRectFnSet(this).SetHeight(area, std::numeric_limits<tools::Long>::max());
+        }
 
         for (SwFrame* pLowerFrame = Lower(); pLowerFrame; pLowerFrame = pLowerFrame->GetNext())
         {