OS X accessibility: implement AXRangeForPosition

This enables users with "Speak text under mouse after delay" set in
VoiceOver Utility > Verbosity > Announcements to hover mouse over text
in QTextEdit and have it spoken by VoiceOver. It also allows users with
Trackpad Commander on to interact with the text area (VO-Shift-arrow
down) and "touch-explore" the text while holding their finger on the
trackpad and moving it around.

[ChangeLog][QtWidgets][Accessibility][OS X] VoiceOver users of QTextEdit
can now use mouse and touch exploration on trackpad to point at text to
have spoken to them.

Change-Id: I6cfaa8b1ff2179cce027b22539ba9ee4f3ee7f3f
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@theqtcompany.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/src/plugins/platforms/cocoa/qcocoaaccessibilityelement.mm b/src/plugins/platforms/cocoa/qcocoaaccessibilityelement.mm
index 1cb51a37bc..47ba50a443 100644
--- a/src/plugins/platforms/cocoa/qcocoaaccessibilityelement.mm
+++ b/src/plugins/platforms/cocoa/qcocoaaccessibilityelement.mm
@@ -419,6 +419,11 @@ static void convertLineOffset(QAccessibleTextInterface *text, int &line, int &of
         NSRange range = [parameter rangeValue];
         QString text = iface->textInterface()->text(range.location, range.location + range.length);
         return [[NSAttributedString alloc] initWithString: text.toNSString()];
+    } else if ([attribute isEqualToString: NSAccessibilityRangeForPositionParameterizedAttribute]) {
+        NSPoint nsPoint = [parameter pointValue];
+        QPoint point(static_cast<int>(nsPoint.x), static_cast<int>(qt_mac_flipYCoordinate(nsPoint.y)));
+        int offset = iface->textInterface()->offsetAtPoint(point);
+        return [NSValue valueWithRange:NSMakeRange(static_cast<NSUInteger>(offset), 1)];
     }
     return nil;
 }