Limit tagging of background objects to images

i.e. don't tag custom shapes and other than bitmap background fills

Change-Id: I1d42012420f59e1e7b62affb8aca5a8c85688423
Reviewed-on: https://gerrit.libreoffice.org/69258
Tested-by: Jenkins
Reviewed-by: Katarina Behrens <Katarina.Behrens@cib.de>

drawinglayer/source/primitive2d/structuretagprimitive2d.cxx

@@ -31,10 +31,12 @@ namespace drawinglayer
         StructureTagPrimitive2D::StructureTagPrimitive2D(
             const vcl::PDFWriter::StructElement& rStructureElement,
             bool bBackground,
+            bool bIsImage,
             const Primitive2DContainer& rChildren)
         :   GroupPrimitive2D(rChildren),
             maStructureElement(rStructureElement),
-            mbBackground(bBackground)
+            mbBackground(bBackground),
+            mbIsImage(bIsImage)
         {
         }
 
@@ -44,7 +46,8 @@ namespace drawinglayer
             {
                 const StructureTagPrimitive2D& rCompare = static_cast<const StructureTagPrimitive2D&>(rPrimitive);
 
-                return (isBackground() == rCompare.isBackground());
+                return (isBackground() == rCompare.isBackground() &&
+                        isImage() == rCompare.isImage());
             }
 
             return false;

drawinglayer/source/processor2d/vclmetafileprocessor2d.cxx

@@ -2213,20 +2213,31 @@ namespace drawinglayer
         {
             // structured tag primitive
             const vcl::PDFWriter::StructElement& rTagElement(rStructureTagCandidate.getStructureElement());
-            const bool bTagUsed(vcl::PDFWriter::NonStructElement != rTagElement);
-            const bool bIsBackground(rStructureTagCandidate.isBackground());
+            bool bTagUsed((vcl::PDFWriter::NonStructElement != rTagElement));
 
             if(mpPDFExtOutDevData && bTagUsed)
             {
-                // Write start tag. For background elements use NonStructElement instead of real element type (e.g. Figure)
-                // to guarantee it gets exported as artifact (tagged PDF)
-                mpPDFExtOutDevData->BeginStructureElement(bIsBackground ? vcl::PDFWriter::NonStructElement : rTagElement);
+                // foreground object: tag as regular structure element
+                if (!rStructureTagCandidate.isBackground())
+                {
+                    mpPDFExtOutDevData->BeginStructureElement(rTagElement);
+                }
+                // background object
+                else
+                {
+                    // background image: tag as artifact
+                    if (rStructureTagCandidate.isImage())
+                        mpPDFExtOutDevData->BeginStructureElement(vcl::PDFWriter::NonStructElement);
+                    // any other background object: do not tag
+                    else
+                        bTagUsed = false;
+                }
             }
 
             // process children normally
             process(rStructureTagCandidate.getChildren());
 
-            if(mpPDFExtOutDevData &&  bTagUsed)
+            if(mpPDFExtOutDevData && bTagUsed)
             {
                 // write end tag
                 mpPDFExtOutDevData->EndStructureElement();

include/drawinglayer/primitive2d/structuretagprimitive2d.hxx

@@ -48,20 +48,23 @@ namespace drawinglayer
             /// the PDF structure element this grouping represents
             vcl::PDFWriter::StructElement           maStructureElement;
 
-            ///Z flag for background contenht that may be handled as
-            /// Tagged PDF '/Artifact'
+            /// flag for background object
             bool                                    mbBackground;
+            /// flag for image (OBJ_GRAF)
+            bool                                    mbIsImage;
 
         public:
             /// constructor
             StructureTagPrimitive2D(
                 const vcl::PDFWriter::StructElement& rStructureElement,
                 bool bBackground,
+                bool bIsImage,
                 const Primitive2DContainer& rChildren);
 
             /// data read access
             const vcl::PDFWriter::StructElement& getStructureElement() const { return maStructureElement; }
             bool isBackground() const { return mbBackground; }
+            bool isImage() const { return mbIsImage; }
 
             /// compare operator
             virtual bool operator==(const BasePrimitive2D& rPrimitive) const override;

sd/source/ui/unoidl/unomodel.cxx

@@ -1804,14 +1804,15 @@ drawinglayer::primitive2d::Primitive2DContainer ImplRenderPaintProc::createRedir
                         // embed Primitive2DSequence in a structure tag element for
                         // exactly this purpose (StructureTagPrimitive2D)
 
-                        //Z
                         const SdrPage* pSdrPage(pObject->getSdrPageFromSdrObject());
                         const bool bBackground(nullptr != pSdrPage && pSdrPage->IsMasterPage());
+                        const bool bImage(pObject->GetObjIdentifier() == OBJ_GRAF);
 
                         const drawinglayer::primitive2d::Primitive2DReference xReference(
                             new drawinglayer::primitive2d::StructureTagPrimitive2D(
                                 eElement,
                                 bBackground,
+                                bImage,
                                 xRetval));
 
                         xRetval = drawinglayer::primitive2d::Primitive2DContainer { xReference };