Respect Password and NoEcho mode while pre-editing

During composition of text using an input method, incomplete characters
should not be visible at all in NoEcho mode, and should be replaced by
the password character in Password mode.

In NoEcho mode, when the cursor is always at position 0, the pre-edit cursor
should also always be at that position so that the UI doesn't give
away the length of the text entered so far.

Task-number: QTBUG-84664
Change-Id: I44a30eee3f5c6fe9fa00073b0a8ac3c333fbaa59
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

1 files changed, 15 insertions, 1 deletions

diff --git a/src/widgets/widgets/qwidgetlinecontrol.cpp b/src/widgets/widgets/qwidgetlinecontrol.cpp
index 77c62b106b..35541b455c 100644
--- a/src/widgets/widgets/qwidgetlinecontrol.cpp
+++ b/src/widgets/widgets/qwidgetlinecontrol.cpp
@@ -573,7 +573,21 @@ void QWidgetLineControl::processInputMethodEvent(QInputMethodEvent *event)
         }
     }
 #ifndef QT_NO_IM
-    setPreeditArea(m_cursor, event->preeditString());
+    // in NoEcho mode, the cursor is always at the beginning of the lineedit
+    switch (m_echoMode) {
+    case QLineEdit::NoEcho:
+        setPreeditArea(0, QString());
+        break;
+    case QLineEdit::Password: {
+        QString preeditString = event->preeditString();
+        preeditString.fill(m_passwordCharacter);
+        setPreeditArea(m_cursor, preeditString);
+        break;
+    }
+    default:
+        setPreeditArea(m_cursor, event->preeditString());
+        break;
+    }
 #endif //QT_NO_IM
     const int oldPreeditCursor = m_preeditCursor;
     m_preeditCursor = event->preeditString().length();