tdf#159565 prerequisite: make hidden sections have zero-height frames

As mentioned in commit bb733957dd39e6f0b9d80bb59eb0177188794797 (tdf#114973
sw: enable SelectAll with hidden para at start/end, 2023-01-27), the hidden
sections didn't have frames. That prevented correct handling of the case
when such a frame was in the beginning of the document.

This change re-implements the hidden section to use 0-height frames, like
hidden paragraphs, as a pre-requisite for a follow-up change.

Some layout breakages noticed while working on this are unit-tested now.

This change needed to handle the case when the first section is hidden, and
then goes a page break with page style. In this case, the page style must
apply to the very first page of the document. Implementing this now, when
the frame that defines the page style is not the first in the document, I
accidentally fixed also the previously broken case when the first paragraph
was hidden. Now the page style defined in the second paragraph's page break
will apply correctly.

This change makes hidden sections break outer section's frames. This means
that when text borders are shown, there will be an artifact in the place of
the hidden sections (a horizontal line breaking outer frame). I suppose
it's not a problem, actually helping to see the layout better, so in line
with the "show text borders" helper functionality. If this proves to be
problematic, this can be handled specially in a follow-up.

[backport: move invalidations from SwSectionFrame::SwClientNotify() to
SwSectionFrame::Modify()]

Change-Id: I14ebf0559b463186aba28902cd10c5cc978ba456
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/163151
Tested-by: Mike Kaganski <mike.kaganski@collabora.com>
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>
Signed-off-by: Xisco Fauli <xiscofauli@libreoffice.org>
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/163477
Tested-by: Jenkins
Reviewed-by: Michael Stahl <michael.stahl@allotropia.de>
(cherry picked from commit ff7f1b59e22092d8548459e75fe912db852f056f)

1 files changed, 5 insertions, 10 deletions

diff --git a/sw/source/core/text/txtfrm.cxx b/sw/source/core/text/txtfrm.cxx
index 82546e533954..676210c0c800 100644
--- a/sw/source/core/text/txtfrm.cxx
+++ b/sw/source/core/text/txtfrm.cxx
@@ -1373,6 +1373,9 @@ bool SwTextFrame::IsHiddenNow() const
         return true;
     }
 
+    if (SwContentFrame::IsHiddenNow())
+        return true;
+
     bool bHiddenCharsHidePara(false);
     bool bHiddenParaField(false);
     if (m_pMergedPara)
@@ -1442,23 +1445,15 @@ bool SwTextFrame::IsHiddenNow() const
             // be visible - check this for the 1st body paragraph
             if (IsInDocBody() && FindPrevCnt() == nullptr)
             {
-                bool isAllHidden(true);
                 for (SwContentFrame const* pNext = FindNextCnt(true);
                         pNext != nullptr; pNext = pNext->FindNextCnt(true))
                 {
-                    if (!pNext->IsTextFrame()
-                        || !static_cast<SwTextFrame const*>(pNext)->IsHiddenNow())
-                    {
-                        isAllHidden = false;
-                        break;
+                    if (!pNext->IsHiddenNow())
+                        return true;
                     }
-                }
-                if (isAllHidden)
-                {
                     SAL_INFO("sw.core", "unhiding one body paragraph");
                     return false;
                 }
-            }
             return true;
         }
     }