tdf#152234 drawinglayer,svx: PDF/UA export: add Alt text to form controls

Specification: ISO 14289-1:2014, Clause: 7.18.1, Test number: 3
A form field whose hidden flag is not set and whose rectangle is not outside the crop-box shall have a TU key present or all its Widget annotations shall have alternative descriptions (in the form of an Alt entry in the enclosing structure elements)

Form controls are weird because they have an SdrObject with the usual
name/title/description plus a property "HelpText" on the control itself
which is already exported as "/TU" on the /Annot unless it's empty.

Exporting the SdrObject properties via ObjectInfoPrimitive2D doesn't
work as tragically that is only created for form controls when painting
to the screen while PDF export takes a detour that needs special
handling.

Change-Id: Id96f7dd13f190ab439c099cd1f4acb70c1c9fdc9
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/149554
Tested-by: Jenkins
Reviewed-by: Michael Stahl <michael.stahl@allotropia.de>
(cherry picked from commit 002a6fee2fbd07c3f0cd1f1ddba39c691130727e)
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/149602
Reviewed-by: Caolán McNamara <caolanm@redhat.com>

5 files changed, 31 insertions, 19 deletions

diff --git a/drawinglayer/source/primitive2d/controlprimitive2d.cxx b/drawinglayer/source/primitive2d/controlprimitive2d.cxx
index c776319e86f5..765a21afacfb 100644
--- a/drawinglayer/source/primitive2d/controlprimitive2d.cxx
+++ b/drawinglayer/source/primitive2d/controlprimitive2d.cxx
@@ -25,6 +25,7 @@
 #include <com/sun/star/uno/XComponentContext.hpp>
 #include <drawinglayer/geometry/viewinformation2d.hxx>
 #include <utility>
+#include <rtl/ustrbuf.hxx>
 #include <vcl/virdev.hxx>
 #include <vcl/svapp.hxx>
 #include <com/sun/star/awt/PosSize.hpp>
@@ -243,20 +244,21 @@ namespace drawinglayer::primitive2d
 
         ControlPrimitive2D::ControlPrimitive2D(
             basegfx::B2DHomMatrix aTransform,
-            uno::Reference< awt::XControlModel > xControlModel)
-        :   maTransform(std::move(aTransform)),
-            mxControlModel(std::move(xControlModel))
-        {
-        }
-
-        ControlPrimitive2D::ControlPrimitive2D(
-            basegfx::B2DHomMatrix aTransform,
             uno::Reference< awt::XControlModel > xControlModel,
-            uno::Reference< awt::XControl > xXControl)
+            uno::Reference<awt::XControl> xXControl,
+            ::std::u16string_view const rTitle,
+            ::std::u16string_view const rDescription)
         :   maTransform(std::move(aTransform)),
             mxControlModel(std::move(xControlModel)),
             mxXControl(std::move(xXControl))
         {
+            ::rtl::OUStringBuffer buf(rTitle);
+            if (!rTitle.empty() && !rDescription.empty())
+            {
+                buf.append(" - ");
+            }
+            buf.append(rDescription);
+            m_AltText = buf.makeStringAndClear();
         }
 
         const uno::Reference< awt::XControl >& ControlPrimitive2D::getXControl() const
diff --git a/drawinglayer/source/processor2d/vclmetafileprocessor2d.cxx b/drawinglayer/source/processor2d/vclmetafileprocessor2d.cxx
index fd60fc2c2808..c18fc7edb30f 100644
--- a/drawinglayer/source/processor2d/vclmetafileprocessor2d.cxx
+++ b/drawinglayer/source/processor2d/vclmetafileprocessor2d.cxx
@@ -1145,8 +1145,6 @@ void VclMetafileProcessor2D::processControlPrimitive2D(
     if (bPDFExport)
     {
         // PDF export. Emulate data handling from UnoControlPDFExportContact
-        // I have now moved describePDFControl to toolkit, thus i can implement the PDF
-        // form control support now as follows
         std::unique_ptr<vcl::PDFWriter::AnyWidget> pPDFControl(
             ::toolkitform::describePDFControl(rXControl, *mpPDFExtOutDevData));
 
@@ -1167,6 +1165,11 @@ void VclMetafileProcessor2D::processControlPrimitive2D(
             pPDFControl->TextFont.SetFontSize(aFontSize);
 
             mpPDFExtOutDevData->BeginStructureElement(vcl::PDFWriter::Form);
+            OUString const& rAltText(rControlPrimitive.GetAltText());
+            if (!rAltText.isEmpty())
+            {
+                mpPDFExtOutDevData->SetAlternateText(rAltText);
+            }
             mpPDFExtOutDevData->CreateControl(*pPDFControl);
             mpPDFExtOutDevData->EndStructureElement();
 
diff --git a/include/drawinglayer/primitive2d/controlprimitive2d.hxx b/include/drawinglayer/primitive2d/controlprimitive2d.hxx
index e3d5a5c0948d..e33c26886cd9 100644
--- a/include/drawinglayer/primitive2d/controlprimitive2d.hxx
+++ b/include/drawinglayer/primitive2d/controlprimitive2d.hxx
@@ -55,6 +55,9 @@ private:
     /// the last used scaling, used from getDecomposition for buffering
     basegfx::B2DVector maLastViewScaling;
 
+    /// yet another special snowflake way to generate PDF Alt text
+    OUString m_AltText;
+
     /** used from getXControl() to create a local awt::XControl which is remembered in mxXControl
                 and from thereon always used and returned by getXControl()
              */
@@ -71,17 +74,14 @@ private:
                           const geometry::ViewInformation2D& rViewInformation) const override;
 
 public:
-    /// constructor
-    ControlPrimitive2D(basegfx::B2DHomMatrix aTransform,
-                       css::uno::Reference<css::awt::XControlModel> xControlModel);
-
-    /** constructor with an additional XControl as parameter to allow to hand it over at incarnation time
+    /** constructor with an optional XControl as parameter to allow to hand it over at incarnation time
         if it exists. This will avoid to create a 2nd one on demand in createXControl()
         and thus double the XControls.
      */
     ControlPrimitive2D(basegfx::B2DHomMatrix aTransform,
                        css::uno::Reference<css::awt::XControlModel> xControlModel,
-                       css::uno::Reference<css::awt::XControl> xXControl);
+                       css::uno::Reference<css::awt::XControl> xXControl,
+                       ::std::u16string_view rTitle, ::std::u16string_view rDescription);
 
     /// data read access
     const basegfx::B2DHomMatrix& getTransform() const { return maTransform; }
@@ -96,6 +96,8 @@ public:
      */
     const css::uno::Reference<css::awt::XControl>& getXControl() const;
 
+    OUString const& GetAltText() const { return m_AltText; }
+
     /// compare operator
     virtual bool operator==(const BasePrimitive2D& rPrimitive) const override;
 
diff --git a/svx/source/sdr/contact/viewcontactofunocontrol.cxx b/svx/source/sdr/contact/viewcontactofunocontrol.cxx
index f99b24372ba7..cc14ae06ad5e 100644
--- a/svx/source/sdr/contact/viewcontactofunocontrol.cxx
+++ b/svx/source/sdr/contact/viewcontactofunocontrol.cxx
@@ -111,7 +111,10 @@ namespace sdr::contact {
             const drawinglayer::primitive2d::Primitive2DReference xRetval(
                 new drawinglayer::primitive2d::ControlPrimitive2D(
                     aTransform,
-                    xControlModel));
+                    xControlModel,
+                    nullptr,
+                    GetSdrObject().GetTitle(),
+                    GetSdrObject().GetDescription()));
 
             rVisitor.visit(xRetval);
         }
diff --git a/svx/source/sdr/contact/viewobjectcontactofunocontrol.cxx b/svx/source/sdr/contact/viewobjectcontactofunocontrol.cxx
index c3233c6d6d23..20217a1985d8 100644
--- a/svx/source/sdr/contact/viewobjectcontactofunocontrol.cxx
+++ b/svx/source/sdr/contact/viewobjectcontactofunocontrol.cxx
@@ -1569,7 +1569,9 @@ namespace sdr::contact {
         // create a primitive and hand over the existing xControl. This will
         // allow the primitive to not need to create another one on demand.
         rContainer.push_back( new ::drawinglayer::primitive2d::ControlPrimitive2D(
-            m_aTransformation, xControlModel, rControl.getControl() ) );
+            m_aTransformation, xControlModel, rControl.getControl(),
+            m_pVOCImpl->getViewContact().GetSdrObject().GetTitle(),
+            m_pVOCImpl->getViewContact().GetSdrObject().GetDescription()) );
     }
 
     sal_uInt32 LazyControlCreationPrimitive2D::getPrimitive2DID() const