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>

2 files changed, 16 insertions, 11 deletions

diff --git a/drawinglayer/source/primitive2d/controlprimitive2d.cxx b/drawinglayer/source/primitive2d/controlprimitive2d.cxx
index 6fe6e57c10d1..372fb61244a0 100644
--- a/drawinglayer/source/primitive2d/controlprimitive2d.cxx
+++ b/drawinglayer/source/primitive2d/controlprimitive2d.cxx
@@ -26,6 +26,7 @@
 #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>
@@ -239,20 +240,21 @@ 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 d82465ceb313..56675ff113ef 100644
--- a/drawinglayer/source/processor2d/vclmetafileprocessor2d.cxx
+++ b/drawinglayer/source/processor2d/vclmetafileprocessor2d.cxx
@@ -1137,8 +1137,6 @@ 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));
 
@@ -1159,6 +1157,11 @@ 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();