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Refactor: use lambdas for visitor pattern in QGraphicsSceneBspTree

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This way, the visitor implementations are directly where they are used,
without the need for a virtual function call. The allocation of the
visitors on the heap was anyway overkill (they could just have been
allocated on the stack where they were used).

Change-Id: Ic41fd285e3a45daaf2e17aa5aeee07e754127a00
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>
This commit is contained in:
Volker Hilsheimer 2022-03-18 15:03:40 +01:00
parent 5e566ab373
commit 6492a9c877
2 changed files with 26 additions and 72 deletions
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80
src/widgets/graphicsview/qgraphicsscene_bsp.cpp
View File

@ -44,57 +44,14 @@
QT_BEGIN_NAMESPACE
class QGraphicsSceneInsertItemBspTreeVisitor : public QGraphicsSceneBspTreeVisitor
{
public:
QGraphicsItem *item;
void visit(QList<QGraphicsItem *> *items) override
{ items->prepend(item); }
};
class QGraphicsSceneRemoveItemBspTreeVisitor : public QGraphicsSceneBspTreeVisitor
{
public:
QGraphicsItem *item;
void visit(QList<QGraphicsItem *> *items) override
{ items->removeAll(item); }
};
class QGraphicsSceneFindItemBspTreeVisitor : public QGraphicsSceneBspTreeVisitor
{
public:
QList<QGraphicsItem *> *foundItems;
bool onlyTopLevelItems;
void visit(QList<QGraphicsItem *> *items) override
{
for (int i = 0; i < items->size(); ++i) {
QGraphicsItem *item = items->at(i);
if (onlyTopLevelItems && item->d_ptr->parent)
item = item->topLevelItem();
if (!item->d_func()->itemDiscovered && item->d_ptr->visible) {
item->d_func()->itemDiscovered = 1;
foundItems->prepend(item);
}
}
}
};
QGraphicsSceneBspTree::QGraphicsSceneBspTree()
: leafCnt(0)
{
insertVisitor = new QGraphicsSceneInsertItemBspTreeVisitor;
removeVisitor = new QGraphicsSceneRemoveItemBspTreeVisitor;
findVisitor = new QGraphicsSceneFindItemBspTreeVisitor;
}
QGraphicsSceneBspTree::~QGraphicsSceneBspTree()
{
delete insertVisitor;
delete removeVisitor;
delete findVisitor;
}
void QGraphicsSceneBspTree::initialize(const QRectF &rect, int depth)
@ -118,14 +75,16 @@ void QGraphicsSceneBspTree::clear()
void QGraphicsSceneBspTree::insertItem(QGraphicsItem *item, const QRectF &rect)
{
insertVisitor->item = item;
climbTree(insertVisitor, rect);
climbTree([item](QList<QGraphicsItem *> *items){
items->prepend(item);
}, rect);
}
void QGraphicsSceneBspTree::removeItem(QGraphicsItem *item, const QRectF &rect)
{
removeVisitor->item = item;
climbTree(removeVisitor, rect);
climbTree([item](QList<QGraphicsItem *> *items){
items->removeAll(item);
}, rect);
}
void QGraphicsSceneBspTree::removeItems(const QSet<QGraphicsItem *> &items)
@ -144,14 +103,22 @@ void QGraphicsSceneBspTree::removeItems(const QSet<QGraphicsItem *> &items)
QList<QGraphicsItem *> QGraphicsSceneBspTree::items(const QRectF &rect, bool onlyTopLevelItems) const
{
QList<QGraphicsItem *> tmp;
findVisitor->foundItems = &tmp;
findVisitor->onlyTopLevelItems = onlyTopLevelItems;
climbTree(findVisitor, rect);
QList<QGraphicsItem *> foundItems;
climbTree([&foundItems, onlyTopLevelItems](QList<QGraphicsItem *> *items) {
for (int i = 0; i < items->size(); ++i) {
QGraphicsItem *item = items->at(i);
if (onlyTopLevelItems && item->d_ptr->parent)
item = item->topLevelItem();
if (!item->d_func()->itemDiscovered && item->d_ptr->visible) {
item->d_func()->itemDiscovered = 1;
foundItems.prepend(item);
}
}
}, rect);
// Reset discovery bits.
for (int i = 0; i < tmp.size(); ++i)
tmp.at(i)->d_ptr->itemDiscovered = 0;
return tmp;
for (const auto &foundItem : qAsConst(foundItems))
foundItem->d_ptr->itemDiscovered = 0;
return foundItems;
}
int QGraphicsSceneBspTree::leafCount() const
@ -230,7 +197,8 @@ void QGraphicsSceneBspTree::initialize(const QRectF &rect, int depth, int index)
}
}
void QGraphicsSceneBspTree::climbTree(QGraphicsSceneBspTreeVisitor *visitor, const QRectF &rect, int index) const
template<typename Visitor>
void QGraphicsSceneBspTree::climbTree(Visitor &&visitor, const QRectF &rect, int index) const
{
if (nodes.isEmpty())
return;
@ -240,7 +208,7 @@ void QGraphicsSceneBspTree::climbTree(QGraphicsSceneBspTreeVisitor *visitor, con
switch (node.type) {
case Node::Leaf: {
visitor->visit(const_cast<QList<QGraphicsItem*>*>(&leaves[node.leafIndex]));
visitor(const_cast<QList<QGraphicsItem*>*>(&leaves[node.leafIndex]));
break;
}
case Node::Vertical:

18
src/widgets/graphicsview/qgraphicsscene_bsp_p.h
View File

@ -61,10 +61,6 @@ QT_REQUIRE_CONFIG(graphicsview);
QT_BEGIN_NAMESPACE
class QGraphicsItem;
class QGraphicsSceneBspTreeVisitor;
class QGraphicsSceneInsertItemBspTreeVisitor;
class QGraphicsSceneRemoveItemBspTreeVisitor;
class QGraphicsSceneFindItemBspTreeVisitor;
class QGraphicsSceneBspTree
{
@ -102,24 +98,14 @@ public:
private:
void initialize(const QRectF &rect, int depth, int index);
void climbTree(QGraphicsSceneBspTreeVisitor *visitor, const QRectF &rect, int index = 0) const;
template<typename Visitor>
void climbTree(Visitor &&visitor, const QRectF &rect, int index = 0) const;
QRectF rectForIndex(int index) const;
QList<Node> nodes;
QList<QList<QGraphicsItem *>> leaves;
int leafCnt;
QRectF rect;
QGraphicsSceneInsertItemBspTreeVisitor *insertVisitor;
QGraphicsSceneRemoveItemBspTreeVisitor *removeVisitor;
QGraphicsSceneFindItemBspTreeVisitor *findVisitor;
};
class QGraphicsSceneBspTreeVisitor
{
public:
virtual ~QGraphicsSceneBspTreeVisitor() { }
virtual void visit(QList<QGraphicsItem *> *items) = 0;
};
QT_END_NAMESPACE