a11y: Fix bug where some characters were not spoken while moving cursor

The problem occurred when we moved the cursor to the penultimate
character of the string, because the boundary condition was wrong. It
is important to realize that the offsets are moved *between* each
character (and also before and after the whole string), just like you
would move a cursor. This means that the offsets can be in the range

  [0, len]     (closed interval)

The problem could only be reproduced with JAWS.

Pick-to: 6.6 6.5 6.2
Fixes: QTBUG-115156
Change-Id: I0c5f05fa391e6c7744ab22d71afe8904b49e89bc
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>

1 files changed, 4 insertions, 4 deletions

diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiatextrangeprovider.cpp b/src/plugins/platforms/windows/uiautomation/qwindowsuiatextrangeprovider.cpp
index 9e46ffd5eb..a62a33cfe2 100644
--- a/src/plugins/platforms/windows/uiautomation/qwindowsuiatextrangeprovider.cpp
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiatextrangeprovider.cpp
@@ -316,14 +316,14 @@ HRESULT QWindowsUiaTextRangeProvider::Move(TextUnit unit, int count, int *pRetVa
 
     int len = textInterface->characterCount();
 
-    if (len < 1)
+    if (len < 1 || count == 0)  // MSDN: "Zero has no effect."
         return S_OK;
 
     if (unit == TextUnit_Character) {
         // Moves the start point, ensuring it lies within the bounds.
-        int start = qBound(0, m_startOffset + count, len - 1);
+        int start = qBound(0, m_startOffset + count, len);
         // If range was initially empty, leaves it as is; otherwise, normalizes it to one char.
-        m_endOffset = (m_endOffset > m_startOffset) ? start + 1 : start;
+        m_endOffset = (m_endOffset > m_startOffset) ? qMin(start + 1, len) : start;
         *pRetVal = start - m_startOffset; // Returns the actually moved distance.
         m_startOffset = start;
     } else {
@@ -394,7 +394,7 @@ HRESULT QWindowsUiaTextRangeProvider::MoveEndpointByUnit(TextPatternRangeEndpoin
 
     if (unit == TextUnit_Character) {
         if (endpoint == TextPatternRangeEndpoint_Start) {
-            int boundedValue = qBound(0, m_startOffset + count, len - 1);
+            int boundedValue = qBound(0, m_startOffset + count, len);
             *pRetVal = boundedValue - m_startOffset;
             m_startOffset = boundedValue;
             m_endOffset = qBound(m_startOffset, m_endOffset, len);