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39
40#ifndef QQUICKDRAGHANDLER_H
41#define QQUICKDRAGHANDLER_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 purely as an
48// implementation detail. 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 "qquickmultipointhandler_p.h"
55#include "qquickdragaxis_p.h"
56
57QT_BEGIN_NAMESPACE
58
59class Q_QUICK_PRIVATE_EXPORT QQuickDragHandler : public QQuickMultiPointHandler
60{
61 Q_OBJECT
62 Q_PROPERTY(QQuickDragAxis * xAxis READ xAxis CONSTANT)
63 Q_PROPERTY(QQuickDragAxis * yAxis READ yAxis CONSTANT)
64 Q_PROPERTY(QVector2D translation READ translation NOTIFY translationChanged)
65 Q_PROPERTY(SnapMode snapMode READ snapMode WRITE setSnapMode NOTIFY snapModeChanged)
66
67public:
68 enum SnapMode {
69 NoSnap = 0,
70 SnapAuto,
71 SnapIfPressedOutsideTarget,
72 SnapAlways
73 };
74 Q_ENUM(SnapMode)
75
76 explicit QQuickDragHandler(QQuickItem *parent = nullptr);
77
78 void handlePointerEventImpl(QQuickPointerEvent *event) override;
79
80 QQuickDragAxis *xAxis() { return &m_xAxis; }
81 QQuickDragAxis *yAxis() { return &m_yAxis; }
82
83 QVector2D translation() const { return m_translation; }
84 void setTranslation(const QVector2D &trans);
85 QQuickDragHandler::SnapMode snapMode() const;
86 void setSnapMode(QQuickDragHandler::SnapMode mode);
87
88 void enforceConstraints();
89
90Q_SIGNALS:
91 void translationChanged();
92 void snapModeChanged();
93
94protected:
95 void onActiveChanged() override;
96 void onGrabChanged(QQuickPointerHandler *grabber, QQuickEventPoint::GrabTransition transition, QQuickEventPoint *point) override;
97
98private:
99 void ungrab();
100 void enforceAxisConstraints(QPointF *localPos);
101 bool targetContainsCentroid();
102 QPointF targetCentroidPosition();
103
104private:
105 QPointF m_pressTargetPos; // We must also store the local targetPos, because we cannot deduce
106 // the press target pos from the scene pos in case there was e.g a
107 // flick in one of the ancestors during the drag.
108 QVector2D m_translation;
109
110 QQuickDragAxis m_xAxis;
111 QQuickDragAxis m_yAxis;
112 QQuickDragHandler::SnapMode m_snapMode = SnapAuto;
113 bool m_pressedInsideTarget = false;
114
115 friend class QQuickDragAxis;
116};
117
118QT_END_NAMESPACE
119
120QML_DECLARE_TYPE(QQuickDragHandler)
121QML_DECLARE_TYPE(QQuickDragAxis)
122
123#endif // QQUICKDRAGHANDLER_H
124