Fixes a regression; missing cursor blink when input mask is set.

I can't say for sure why q*linecontrol passes an empty rect to
the updateNeeded() signal when an input mask is set; presumably
the empty rect at some point has meant "full update", but there
are a few problems with this. Surely a full update is wrong,
even if the semantics have been lost in translation somewhere
(likely the qlinecontrol refactoring). This fix ensures
that empty rects from updateNeeded() are interpreted as a request
to update the whole widget. A further improvement would be to
ensure the line control doesn't request a full update when an
input mask is set. The cursor is usually wider when a mask is
set but because of QLineEdit::paintEvent()'s implementation,
there is currently a mismatch between the cursor width as seen
by q*linecontrol and what is actually drawn, which causes
rendering artifacts if updateNeeded() sends the cursorRect().

Since QLineEdit and Q*LineControl aren't actively developed, it's
best to keep this fix minimal, although the performance cost of
updating the whole line edit when an input mask is set is
unfortunate.

cherry-picked from qt5/qtbase a9cda515177db1615f8d47becf2aa781f26955ae

Task-number: QTBUG-7174
Change-Id: Ie51e015d760915e07b0220b770f04fc958d93a12
Reviewed-by: Girish Ramakrishnan <girish.1.ramakrishnan@nokia.com>

1 files changed, 25 insertions, 0 deletions

diff --git a/tests/auto/qlineedit/tst_qlineedit.cpp b/tests/auto/qlineedit/tst_qlineedit.cpp
index 9000fd0..ec57ce2 100644
--- a/tests/auto/qlineedit/tst_qlineedit.cpp
+++ b/tests/auto/qlineedit/tst_qlineedit.cpp
@@ -282,6 +282,7 @@ private slots:
     void taskQTBUG_7395_readOnlyShortcut();
     void QTBUG697_paletteCurrentColorGroup();
     void QTBUG13520_textNotVisible();
+    void QTBUG7174_inputMaskCursorBlink();
 
 #ifdef QT3_SUPPORT
     void validateAndSet_data();
@@ -3823,6 +3824,30 @@ void tst_QLineEdit::QTBUG13520_textNotVisible()
 
 }
 
+class UpdateRegionLineEdit : public QLineEdit
+{
+public:
+    QRegion updateRegion;
+protected:
+    void paintEvent(QPaintEvent *event)
+    {
+        updateRegion = event->region();
+    }
+};
+
+void tst_QLineEdit::QTBUG7174_inputMaskCursorBlink()
+{
+    UpdateRegionLineEdit edit;
+    edit.setInputMask(QLatin1String("AAAA"));
+    edit.setFocus();
+    edit.setText(QLatin1String("AAAA"));
+    edit.show();
+    QRect cursorRect = edit.inputMethodQuery(Qt::ImMicroFocus).toRect();
+    QTest::qWaitForWindowShown(&edit);
+    edit.updateRegion = QRegion();
+    QTest::qWait(QApplication::cursorFlashTime());
+    QVERIFY(edit.updateRegion.contains(cursorRect));
+}
 
 void tst_QLineEdit::bidiVisualMovement_data()
 {