qt a11y: Add mapping for relations added in Qt 6.6

Map `AccessibleRelationType::CONTENT_FLOWS_FROM`,
`AccessibleRelationType::CONTENT_FLOWS_TO` and
`AccessibleRelationType::DESCRIBED_BY` to the
Qt equivalents added in Qt 6.6 and vice versa.

As described in more detail in

commit e55713dffbe8d8eba18068f6c2af14c10b787220
Date:   Fri Feb 17 15:25:37 2023 +0100

qt a11y: Invert relation type to match Qt's semantic

, the "inverse" relation needs to be used when
mapping to/from the Qt relation.

For example the Orca screen reader on Linux makes
use of the FlOWS_FROM and FLOWS_TO relations.
So far, when using the qt6 VCL plugin with Orca
running, moving focus to a Writer paragraph resulted
in these warnings being emitted:

warn:vcl.qt:220606:220606:vcl/qt6/../qt5/QtAccessibleWidget.cxx:218: Unmatched relation: 1
warn:vcl.qt:220606:220606:vcl/qt6/../qt5/QtAccessibleWidget.cxx:218: Unmatched relation: 2

and thus Orca not being able to make use of those relations.

Sample use in Accerciser's Python console, with a Writer document
having three paragraphs with texts "First", "second", and "third"
and the a11y object of the second paragraph's a11y object selected
in Accerciser's a11y tree view:

In [1]: acc.queryText().getStringAtOffset(0, pyatspi.TEXT_GRANULARITY_PARAGRAPH)
Out[1]: ('second', 0, 6)
In [2]: acc.get_relation_set()
Out[2]:
[<Atspi.Relation object at 0x7fccc36862c0 (AtspiRelation at 0x421e100)>,
<Atspi.Relation object at 0x7fccc358c280 (AtspiRelation at 0x4493c60)>]
In [3]: first_relation = acc.get_relation_set()[0]
In [4]: first_relation.get_n_targets()
Out[4]: 1
In [5]: first_relation.get_relation_type()
Out[5]: <enum ATSPI_RELATION_FLOWS_FROM of type Atspi.RelationType>
In [6]: first_relation.get_target(0)
Out[6]: <Atspi.Accessible object at 0x7fccc35aa4c0 (AtspiAccessible at 0x4479820)>
In [7]: first_relation.get_target(0).queryText().getStringAtOffset(0, 1)
Out[7]: ('First', 0, 5)
In [8]: second_relation = acc.get_relation_set()[1]
In [9]: second_relation.get_n_targets()
Out[9]: 1
In [10]: second_relation.get_relation_type()
Out[10]: <enum ATSPI_RELATION_FLOWS_TO of type Atspi.RelationType>
In [11]: second_relation.get_target(0).queryText().getStringAtOffset(0,1)
Out[11]: ('third', 0, 5)

(QTBUG-105864 [1] also has a sample doc and pyatspi script that can be used
for testing.)

Qt commit adding the relations [2]:

commit f5358e5932bc8701621389c265c4ea86c92c536c
Author: Michael Weghorn <m.weghorn@posteo.de>
Date:   Fri Feb 17 13:48:38 2023 +0100

a11y: Add new relations DescriptionFor, Described, Flows{From,To}

This is equivalent to the corresponding relation types defined
in the IAccessible2 spec [1] (IA2_RELATION_DESCRIPTION_FOR,
IA2_RELATION_DESCRIBED_BY, IA2_RELATION_FLOWS_FROM,
IA2_RELATION_FLOWS_TO) and for AT-SPI on Linux [2]
(relation types ATSPI_RELATION_DESCRIPTION_FOR,
ATSPI_RELATION_DESCRIBED_BY, ATSPI_RELATION_FLOWS_FROM,
ATSPI_RELATION_FLOWS_TO).

User Interface Automation (UIA) on Windows also has corresponding
properties for 3 of them [3]: UIA_DescribedByPropertyId,
UIA_FlowsFromPropertyId, UIA_FlowsToPropertyId.

This commit adds the new flags and implements the mapping for
the AT-SPI case.
Note that the relation type is conceptually always "inverted"
when comparing Qt and AT-SPI (or Qt and UIA)
as clarified in afbfe30093d49eff0ec4c28c220d33c233b9f807.

"QAccessible::Description" instead of "QAccessible::DescriptionFor"
would align better with the naming scheme of the other relations, but
that is already used in the Text enum.

[1] https://accessibility.linuxfoundation.org/a11yspecs/ia2/docs/html/group__grp_relations.html
[2] https://lazka.github.io/pgi-docs/Atspi-2.0/enums.html#Atspi.RelationType
[3] https://docs.microsoft.com/en-us/windows/win32/winauto/uiauto-automation-element-propids

[ChangeLog][QtGui][QAccessible::RelationFlag] Added new relation
flags DescriptionFor, Described, FlowsFrom and FlowsTo.

Fixes: QTBUG-105864
Change-Id: If2d46099eeea75e177358c821d1ae833a553bd0e
Reviewed-by: Jan Arve Sæther <jan-arve.saether@qt.io>

[1] https://bugreports.qt.io/browse/QTBUG-105864
[2] https://code.qt.io/cgit/qt/qtbase.git/commit/?id=f5358e5932bc8701621389c265c4ea86c92c536c

Change-Id: I6e5d78fb26f62a6f1745d4f94647e8dc0fe2abfd
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/138687
Tested-by: Jenkins
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>

1 files changed, 21 insertions, 3 deletions

diff --git a/vcl/qt5/QtAccessibleWidget.cxx b/vcl/qt5/QtAccessibleWidget.cxx
index 7a55bae884f5..13823006b6cd 100644
--- a/vcl/qt5/QtAccessibleWidget.cxx
+++ b/vcl/qt5/QtAccessibleWidget.cxx
@@ -223,21 +223,28 @@ QAccessible::Relation lcl_matchUnoRelation(short relationType)
     // Qt semantics is the other way around
     switch (relationType)
     {
+#if QT_VERSION >= QT_VERSION_CHECK(6, 6, 0)
+        case AccessibleRelationType::CONTENT_FLOWS_FROM:
+            return QAccessible::FlowsTo;
+        case AccessibleRelationType::CONTENT_FLOWS_TO:
+            return QAccessible::FlowsFrom;
+#endif
         case AccessibleRelationType::CONTROLLED_BY:
             return QAccessible::Controller;
         case AccessibleRelationType::CONTROLLER_FOR:
             return QAccessible::Controlled;
+#if QT_VERSION >= QT_VERSION_CHECK(6, 6, 0)
+        case AccessibleRelationType::DESCRIBED_BY:
+            return QAccessible::DescriptionFor;
+#endif
         case AccessibleRelationType::LABELED_BY:
             return QAccessible::Label;
         case AccessibleRelationType::LABEL_FOR:
             return QAccessible::Labelled;
         case AccessibleRelationType::INVALID:
-        case AccessibleRelationType::CONTENT_FLOWS_FROM:
-        case AccessibleRelationType::CONTENT_FLOWS_TO:
         case AccessibleRelationType::MEMBER_OF:
         case AccessibleRelationType::SUB_WINDOW_OF:
         case AccessibleRelationType::NODE_CHILD_OF:
-        case AccessibleRelationType::DESCRIBED_BY:
         default:
             SAL_WARN("vcl.qt", "Unmatched relation: " << relationType);
             return {};
@@ -253,10 +260,21 @@ short lcl_matchQtRelation(QAccessible::Relation relationType)
             return AccessibleRelationType::CONTROLLER_FOR;
         case QAccessible::Controller:
             return AccessibleRelationType::CONTROLLED_BY;
+#if QT_VERSION >= QT_VERSION_CHECK(6, 6, 0)
+        case QAccessible::DescriptionFor:
+            return AccessibleRelationType::DESCRIBED_BY;
+        case QAccessible::FlowsFrom:
+            return AccessibleRelationType::CONTENT_FLOWS_TO;
+        case QAccessible::FlowsTo:
+            return AccessibleRelationType::CONTENT_FLOWS_FROM;
+#endif
         case QAccessible::Labelled:
             return AccessibleRelationType::LABEL_FOR;
         case QAccessible::Label:
             return AccessibleRelationType::LABELED_BY;
+#if QT_VERSION >= QT_VERSION_CHECK(6, 6, 0)
+        case QAccessible::Described:
+#endif
         default:
             SAL_WARN("vcl.qt", "Unmatched relation: " << relationType);
     }