Obsolete Members for QGraphicsScene

以下成員源於類 QGraphicsScene 被棄用。 提供它們是為使舊源代碼能繼續工作。強烈建議不要在新代碼中使用它們。

保護函數

(棄用) virtual void

drawItems (QPainter * painter , int numItems , QGraphicsItem *[] items , const QStyleOptionGraphicsItem [] options , QWidget * widget = nullptr)

成員函數文檔編製

[virtual protected] void QGraphicsScene:: drawItems ( QPainter * painter , int numItems , QGraphicsItem *[] items , const QStyleOptionGraphicsItem [] options , QWidget * widget = nullptr)

This function is deprecated. We strongly advise against using it in new code.

Paints the given items 使用提供 painter , after the background has been drawn, and before the foreground has been drawn. All painting is done in scene coordinates. Before drawing each item, the painter must be transformed using QGraphicsItem::sceneTransform ().

The options parameter is the list of style option objects for each item in items 。 numItems parameter is the number of items in items and options in options 。 widget parameter is optional; if specified, it should point to the widget that is being painted on.

The default implementation prepares the painter matrix, and calls QGraphicsItem::paint () on all items. Reimplement this function to provide custom painting of all items for the scene; gaining complete control over how each item is drawn. In some cases this can increase drawing performance significantly.

範例：

void CustomScene::drawItems(QPainter *painter, int numItems,
                            QGraphicsItem *items[],
                            const QStyleOptionGraphicsItem options[],
                            QWidget *widget)
{
    for (int i = 0; i < numItems; ++i) {
         // Draw the item
         painter->save();
         painter->setTransform(items[i]->sceneTransform(), true);
         items[i]->paint(painter, &options[i], widget);
         painter->restore();
     }
}
					

Since Qt 4.6, this function is not called anymore unless the QGraphicsView::IndirectPainting flag is given as an Optimization flag.

另請參閱 drawBackground () 和 drawForeground ().