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39
40#ifndef QGRAPHICSSCENELINEARINDEX_H
41#define QGRAPHICSSCENELINEARINDEX_H
42
43//
44// W A R N I N G
45// -------------
46//
47// This file is not part of the Qt API. It exists for the convenience
48// of other Qt classes. This header file may change from version to
49// version without notice, or even be removed.
50//
51// We mean it.
52//
53
54#include <QtWidgets/private/qtwidgetsglobal_p.h>
55
56#include <QtCore/qrect.h>
57#include <QtCore/qlist.h>
58#include <QtWidgets/qgraphicsitem.h>
59#include <private/qgraphicssceneindex_p.h>
60
61QT_REQUIRE_CONFIG(graphicsview);
62
63QT_BEGIN_NAMESPACE
64
65class Q_AUTOTEST_EXPORT QGraphicsSceneLinearIndex : public QGraphicsSceneIndex
66{
67 Q_OBJECT
68
69public:
70 QGraphicsSceneLinearIndex(QGraphicsScene *scene = nullptr) : QGraphicsSceneIndex(scene), m_numSortedElements(0)
71 { }
72
73 QList<QGraphicsItem *> items(Qt::SortOrder order = Qt::DescendingOrder) const override
74 { Q_UNUSED(order); return m_items; }
75
76 virtual QList<QGraphicsItem *> estimateItems(const QRectF &rect, Qt::SortOrder order) const override
77 {
78 Q_UNUSED(rect);
79 Q_UNUSED(order);
80 return m_items;
81 }
82
83protected :
84 virtual void clear() override
85 {
86 m_items.clear();
87 m_numSortedElements = 0;
88 }
89
90 virtual void addItem(QGraphicsItem *item) override
91 { m_items << item; }
92
93 virtual void removeItem(QGraphicsItem *item) override
94 {
95 // Sort m_items if needed
96 if (m_numSortedElements < m_items.size())
97 {
98 std::sort(first: m_items.begin() + m_numSortedElements, last: m_items.end() );
99 std::inplace_merge(first: m_items.begin(), middle: m_items.begin() + m_numSortedElements, last: m_items.end());
100 m_numSortedElements = m_items.size();
101 }
102
103 QList<QGraphicsItem*>::iterator element = std::lower_bound(m_items.begin(), m_items.end(), item);
104 if (element != m_items.end() && *element == item)
105 {
106 m_items.erase(pos: element);
107 --m_numSortedElements;
108 }
109 }
110
111private:
112 QList<QGraphicsItem*> m_items;
113 int m_numSortedElements;
114};
115
116QT_END_NAMESPACE
117
118#endif // QGRAPHICSSCENELINEARINDEX_H
119

source code of qtbase/src/widgets/graphicsview/qgraphicsscenelinearindex_p.h