QQuickPane: calculate content size in C++ unless explicitly defined

No more need for the clumsy and slow contentWidth and contentHeight
bindings in Pane and its derivatives.

QmlBench on TX1:

    Pane: 26.4 -> 32.8 frames (~24%)
    Frame: 25.4 -> 31 frames (~22%)
    GroupBox: 28.6 -> 32 frames (~12%)

Change-Id: I4ba1d46ba6328de2ee0955c241d4b090127f6b85
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

1 files changed, 5 insertions, 2 deletions

diff --git a/src/quicktemplates2/qquickpane_p.h b/src/quicktemplates2/qquickpane_p.h
index 759c59d8..53bf7067 100644
--- a/src/quicktemplates2/qquickpane_p.h
+++ b/src/quicktemplates2/qquickpane_p.h
@@ -58,20 +58,23 @@ class QQuickPanePrivate;
 class Q_QUICKTEMPLATES2_PRIVATE_EXPORT QQuickPane : public QQuickControl
 {
     Q_OBJECT
-    Q_PROPERTY(qreal contentWidth READ contentWidth WRITE setContentWidth NOTIFY contentWidthChanged FINAL)
-    Q_PROPERTY(qreal contentHeight READ contentHeight WRITE setContentHeight NOTIFY contentHeightChanged FINAL)
+    Q_PROPERTY(qreal contentWidth READ contentWidth WRITE setContentWidth RESET resetContentWidth NOTIFY contentWidthChanged FINAL)
+    Q_PROPERTY(qreal contentHeight READ contentHeight WRITE setContentHeight RESET resetContentHeight NOTIFY contentHeightChanged FINAL)
     Q_PROPERTY(QQmlListProperty<QObject> contentData READ contentData FINAL)
     Q_PROPERTY(QQmlListProperty<QQuickItem> contentChildren READ contentChildren NOTIFY contentChildrenChanged FINAL)
     Q_CLASSINFO("DefaultProperty", "contentData")
 
 public:
     explicit QQuickPane(QQuickItem *parent = nullptr);
+    ~QQuickPane();
 
     qreal contentWidth() const;
     void setContentWidth(qreal width);
+    void resetContentWidth();
 
     qreal contentHeight() const;
     void setContentHeight(qreal height);
+    void resetContentHeight();
 
     QQmlListProperty<QObject> contentData();
     QQmlListProperty<QQuickItem> contentChildren();