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, 2 insertions, 1 deletions

diff --git a/src/gui/widgets/qlineedit_p.cpp b/src/gui/widgets/qlineedit_p.cpp
index 08b0685..c2cb3fc 100644
--- a/src/gui/widgets/qlineedit_p.cpp
+++ b/src/gui/widgets/qlineedit_p.cpp
@@ -61,9 +61,10 @@ const int QLineEditPrivate::horizontalMargin(2);
 
 QRect QLineEditPrivate::adjustedControlRect(const QRect &rect) const
 {
+    QRect widgetRect = !rect.isEmpty() ? rect : q_func()->rect();
     QRect cr = adjustedContentsRect();
     int cix = cr.x() - hscroll + horizontalMargin;
-    return rect.translated(QPoint(cix, vscroll));
+    return widgetRect.translated(QPoint(cix, vscroll));
 }
 
 int QLineEditPrivate::xToPos(int x, QTextLine::CursorPosition betweenOrOn) const