a11y: Add XAccessibleValue::getMinimumIncrement method

Add a method 'getMinimumIncrement' to the XAccessibleValue interface.
The method returns the minimal increment by which the value represented by
the object can be adjusted.

The main motivation is to expose this to AT-SPI, so it can be retrieved e.g.
by libatspi's 'atspi_value_get_minimum_increment' function [1],
s. the note in Change-Id: I8af326c2d24c1801147a56ea2e2a886ab42ac634
"a11y: Expose FormattedField as spinbox" for more details.

The implementation relevant for the 'FormattedField' class is in
'SVTXAccessibleNumericField::getMinimumIncrement', which returns
the spin size.

While at it, also move the comment in sw/source/core/access/acccell.hxx
mentioning what methods are overriden for the 'XAccessibleValue' interface
to the right place.

[1] https://developer.gnome.org/libatspi/stable/libatspi-atspi-value.html#atspi-value-get-minimum-increment

Change-Id: Ie148a4e1cedbdbb5964f8565c81611d3480465cb
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/119596
Tested-by: Jenkins
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>

1 files changed, 6 insertions, 0 deletions

diff --git a/sc/source/ui/Accessibility/AccessibleCellBase.cxx b/sc/source/ui/Accessibility/AccessibleCellBase.cxx
index 5d7e1d2c612c..03ecf65af241 100644
--- a/sc/source/ui/Accessibility/AccessibleCellBase.cxx
+++ b/sc/source/ui/Accessibility/AccessibleCellBase.cxx
@@ -259,6 +259,12 @@ uno::Any SAL_CALL
     return uno::Any(-DBL_MAX);
 }
 
+uno::Any SAL_CALL
+    ScAccessibleCellBase::getMinimumIncrement(  )
+{
+    return uno::Any();
+}
+
     //=====  XServiceInfo  ====================================================
 
 OUString SAL_CALL ScAccessibleCellBase::getImplementationName()