QWidget::grab: Add a default value for the QRect parameter.

The documentation is misleading in that a default-constructed
rectangle that has size = 0 causes the entire widget to be
painted; this happens only if the one of the size values is
 < 0.

Add a default value such that size < 0 and the entire widget is
painted based on the rationale that a size = 0 might be the result
of some calculation and it would be unexpected to get a pixmap
containing the entire widget in that case.

Change-Id: I2a5fb38cd407b4b64348213101d8196b2c40ad9a
Reviewed-by: Samuel Rødal <samuel.rodal@nokia.com>

2 files changed, 3 insertions, 5 deletions

diff --git a/src/widgets/kernel/qwidget.cpp b/src/widgets/kernel/qwidget.cpp
index 3d0ffd9269..355ef5bee0 100644
--- a/src/widgets/kernel/qwidget.cpp
+++ b/src/widgets/kernel/qwidget.cpp
@@ -4765,10 +4765,8 @@ static void sendResizeEvents(QWidget *target)
     given \a rectangle. If the \a widget has any children, then
     they are also painted in the appropriate positions.
 
-    If no rectangle is specified (the default) the entire widget is
-    painted.
-
-    Replacement for Qt 4's QPixmap::grabWidget().
+    If a rectangle with an invalid size is specified  (the default),
+    the entire widget is painted.
 
     \sa render(), QPixmap
 */
diff --git a/src/widgets/kernel/qwidget.h b/src/widgets/kernel/qwidget.h
index b7a5e26690..0110a3850b 100644
--- a/src/widgets/kernel/qwidget.h
+++ b/src/widgets/kernel/qwidget.h
@@ -351,7 +351,7 @@ public:
                 const QRegion &sourceRegion = QRegion(),
                 RenderFlags renderFlags = RenderFlags(DrawWindowBackground | DrawChildren));
 
-    Q_INVOKABLE QPixmap grab(const QRect &rectangle);
+    Q_INVOKABLE QPixmap grab(const QRect &rectangle = QRect(QPoint(0, 0), QSize(-1, -1)));
 
 #ifndef QT_NO_GRAPHICSEFFECT
     QGraphicsEffect *graphicsEffect() const;