tdf#126533 docx export: page background vml fill: tiles/patterns

This patch only benefits LO. MSO ignores "frame" and always
treats page background as it if were tiled,
but that is a trait we do NOT want to mimic.

Textures are the primary fill type that needs to be tiled
(instead of scaled/stretched).

LO export also treats patterns as tiled bitmaps,
and the end result of exporting as a tile looks the same
as the original pattern.
It just loses HOW the page background (i.e. as a pattern)
but that is very low value. It is rather difficult
to export as a true pattern and just not worth the effort
of identifying the correct fore/background colors,
converting to b&w image, and inverting the B&W image
if the first pixel is white instead of black.

[Hatching seems similar to patterns,
but rarely (and only coincidentally) would it tile well.
I think hatching is a new DML-only thing.
Hatching is not in the page background UI of MS Word.
LO just exports any hatching as a solid color.]

Change-Id: I5cd3f1c6e380edb5e5b21900bad289fa298574e2
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/163206
Tested-by: Jenkins
Reviewed-by: Justin Luth <jluth@mail.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/sw/source/filter/ww8/docxexport.cxx b/sw/source/filter/ww8/docxexport.cxx
index fcb55e19c314..466fe652d5dd 100644
--- a/sw/source/filter/ww8/docxexport.cxx
+++ b/sw/source/filter/ww8/docxexport.cxx
@@ -55,6 +55,7 @@
 #include <oox/ole/olehelper.hxx>
 
 #include <svx/svdpage.hxx>
+#include <svx/xflbmtit.hxx>
 
 #include <map>
 #include <algorithm>
@@ -1914,6 +1915,7 @@ void DocxExport::WriteMainText()
         m_pDocumentFS->startElementNS(XML_w, XML_background, FSNS(XML_w, XML_color),
                                       msfilter::util::ConvertColor(oBrush->GetColor()));
 
+        const SwAttrSet& rPageStyleAttrSet = m_rDoc.GetPageDesc(0).GetMaster().GetAttrSet();
         const GraphicObject* pGraphicObj = oBrush->GetGraphicObject();
         if (pGraphicObj) // image/pattern/texture
         {
@@ -1922,8 +1924,12 @@ void DocxExport::WriteMainText()
             {
                 m_pDocumentFS->startElementNS(XML_v, XML_background);
 
+                // Although MSO treats everything as tile, it is better for LO to not always tile
+                OString sType = "frame"_ostr; // single image
+                if (rPageStyleAttrSet.Get(XATTR_FILLBMP_TILE).GetValue())
+                    sType = "tile"_ostr; // primarily for patterns / textures
                 m_pDocumentFS->singleElementNS(XML_v, XML_fill, FSNS(XML_r, XML_id), aRelId,
-                                            XML_type, "frame");
+                                            XML_type, sType);
 
                 m_pDocumentFS->endElementNS(XML_v, XML_background);
             }