QGraphicsItem类-优快云博客

本文详细介绍了QGraphicsItem在Qt图形系统中的核心作用，包括其作为图形项基类的特性，以及公有类型、函数、保护函数和相关非成员函数，展示了图形项的缓存模式、变化通知和事件处理机制。

QGraphicsItem（图形项）类是 QGraphicsScene中所有图形项的基类。

Header:	#include <QGraphicsItem>
CMake:	find_package(Qt6 REQUIRED COMPONENTS Widgets) target_link_libraries(mytarget PRIVATE Qt6::Widgets)
qmake:	QT += widgets
Inherited By:	QAbstractGraphicsShapeItem, QGraphicsItemGroup, QGraphicsLineItem, QGraphicsObject, and QGraphicsPixmapItem

详细描述>>>

【公有类型】

enum	CacheMode { NoCache, ItemCoordinateCache, DeviceCoordinateCache }
enum	GraphicsItemChange { ItemEnabledChange, ItemEnabledHasChanged, ItemPositionChange, ItemPositionHasChanged, ItemTransformChange, …, ItemScenePositionHasChanged }
enum	GraphicsItemFlag { ItemIsMovable, ItemIsSelectable, ItemIsFocusable, ItemClipsToShape, ItemClipsChildrenToShape, …, ItemContainsChildrenInShape }
flags	GraphicsItemFlags
enum	PanelModality { NonModal, PanelModal, SceneModal }
enum	anonymous { Type, UserType }

【公有函数】

	QGraphicsItem(QGraphicsItem *parent = nullptr)
virtual	~QGraphicsItem()
bool	acceptDrops() const
bool	acceptHoverEvents() const
bool	acceptTouchEvents() const
Qt::MouseButtons	acceptedMouseButtons() const
virtual void	advance(int phase)
virtual QRectF	boundingRect() const = 0
QRegion	boundingRegion(const QTransform &itemToDeviceTransform) const
qreal	boundingRegionGranularity() const
QGraphicsItem::CacheMode	cacheMode() const
QList<QGraphicsItem *>	childItems() const
QRectF	childrenBoundingRect() const
void	clearFocus()
QPainterPath	clipPath() const
virtual bool	collidesWithItem(const QGraphicsItem *other, Qt::ItemSelectionMode mode = Qt::IntersectsItemShape) const
virtual bool	collidesWithPath(const QPainterPath &path, Qt::ItemSelectionMode mode = Qt::IntersectsItemShape) const
QList<QGraphicsItem *>	collidingItems(Qt::ItemSelectionMode mode = Qt::IntersectsItemShape) const
QGraphicsItem *	commonAncestorItem(const QGraphicsItem *other) const
virtual bool	contains(const QPointF &point) const
QCursor	cursor() const
QVariant	data(int key) const
QTransform	deviceTransform(const QTransform &viewportTransform) const
qreal	effectiveOpacity() const
void	ensureVisible(const QRectF &rect = QRectF(), int xmargin = 50, int ymargin = 50)
void	ensureVisible(qreal x, qreal y, qreal w, qreal h, int xmargin = 50, int ymargin = 50)
bool	filtersChildEvents() const
QGraphicsItem::GraphicsItemFlags	flags() const
QGraphicsItem *	focusItem() const
QGraphicsItem *	focusProxy() const
void	grabKeyboard()
void	grabMouse()
QGraphicsEffect *	graphicsEffect() const
QGraphicsItemGroup *	group() const
bool	hasCursor() const
bool	hasFocus() const
void	hide()
Qt::InputMethodHints	inputMethodHints() const
void	installSceneEventFilter(QGraphicsItem *filterItem)
bool	isActive() const
bool	isAncestorOf(const QGraphicsItem *child) const
bool	isBlockedByModalPanel(QGraphicsItem **blockingPanel = nullptr) const
bool	isClipped() const
bool	isEnabled() const
bool	isObscured(const QRectF &rect = QRectF()) const
bool	isObscured(qreal x, qreal y, qreal w, qreal h) const
virtual bool	isObscuredBy(const QGraphicsItem *item) const
bool	isPanel() const
bool	isSelected() const
bool	isUnderMouse() const
bool	isVisible() const
bool	isVisibleTo(const QGraphicsItem *parent) const
bool	isWidget() const
bool	isWindow() const
QTransform	itemTransform(const QGraphicsItem *other, bool *ok = nullptr) const
QPointF	mapFromItem(const QGraphicsItem *item, const QPointF &point) const
QPolygonF	mapFromItem(const QGraphicsItem *item, const QRectF &rect) const
QPolygonF	mapFromItem(const QGraphicsItem *item, const QPolygonF &polygon) const
QPainterPath	mapFromItem(const QGraphicsItem *item, const QPainterPath &path) const
QPointF	mapFromItem(const QGraphicsItem *item, qreal x, qreal y) const
QPolygonF	mapFromItem(const QGraphicsItem *item, qreal x, qreal y, qreal w, qreal h) const
QPointF	mapFromParent(const QPointF &point) const
QPolygonF	mapFromParent(const QRectF &rect) const
QPolygonF	mapFromParent(const QPolygonF &polygon) const
QPainterPath	mapFromParent(const QPainterPath &path) const
QPointF	mapFromParent(qreal x, qreal y) const
QPolygonF	mapFromParent(qreal x, qreal y, qreal w, qreal h) const
QPointF	mapFromScene(const QPointF &point) const
QPolygonF	mapFromScene(const QRectF &rect) const
QPolygonF	mapFromScene(const QPolygonF &polygon) const
QPainterPath	mapFromScene(const QPainterPath &path) const
QPointF	mapFromScene(qreal x, qreal y) const
QPolygonF	mapFromScene(qreal x, qreal y, qreal w, qreal h) const
QRectF	mapRectFromItem(const QGraphicsItem *item, const QRectF &rect) const
QRectF	mapRectFromItem(const QGraphicsItem *item, qreal x, qreal y, qreal w, qreal h) const
QRectF	mapRectFromParent(const QRectF &rect) const
QRectF	mapRectFromParent(qreal x, qreal y, qreal w, qreal h) const
QRectF	mapRectFromScene(const QRectF &rect) const
QRectF	mapRectFromScene(qreal x, qreal y, qreal w, qreal h) const
QRectF	mapRectToItem(const QGraphicsItem *item, const QRectF &rect) const
QRectF	mapRectToItem(const QGraphicsItem *item, qreal x, qreal y, qreal w, qreal h) const
QRectF	mapRectToParent(const QRectF &rect) const
QRectF	mapRectToParent(qreal x, qreal y, qreal w, qreal h) const
QRectF	mapRectToScene(const QRectF &rect) const
QRectF	mapRectToScene(qreal x, qreal y, qreal w, qreal h) const
QPointF	mapToItem(const QGraphicsItem *item, const QPointF &point) const
QPolygonF	mapToItem(const QGraphicsItem *item, const QRectF &rect) const
QPolygonF	mapToItem(const QGraphicsItem *item, const QPolygonF &polygon) const
QPainterPath	mapToItem(const QGraphicsItem *item, const QPainterPath &path) const
QPointF	mapToItem(const QGraphicsItem *item, qreal x, qreal y) const
QPolygonF	mapToItem(const QGraphicsItem *item, qreal x, qreal y, qreal w, qreal h) const
QPointF	mapToParent(const QPointF &point) const
QPolygonF	mapToParent(const QRectF &rect) const
QPolygonF	mapToParent(const QPolygonF &polygon) const
QPainterPath	mapToParent(const QPainterPath &path) const
QPointF	mapToParent(qreal x, qreal y) const
QPolygonF	mapToParent(qreal x, qreal y, qreal w, qreal h) const
QPointF	mapToScene(const QPointF &point) const
QPolygonF	mapToScene(const QRectF &rect) const
QPolygonF	mapToScene(const QPolygonF &polygon) const
QPainterPath	mapToScene(const QPainterPath &path) const
QPointF	mapToScene(qreal x, qreal y) const
QPolygonF	mapToScene(qreal x, qreal y, qreal w, qreal h) const
void	moveBy(qreal dx, qreal dy)
qreal	opacity() const
virtual QPainterPath	opaqueArea() const
virtual void	paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget = nullptr) = 0
QGraphicsItem *	panel() const
QGraphicsItem::PanelModality	panelModality() const
QGraphicsItem *	parentItem() const
QGraphicsObject *	parentObject() const
QGraphicsWidget *	parentWidget() const
QPointF	pos() const
void	removeSceneEventFilter(QGraphicsItem *filterItem)
void	resetTransform()
qreal	rotation() const
qreal	scale() const
QGraphicsScene *	scene() const
QRectF	sceneBoundingRect() const
QPointF	scenePos() const
QTransform	sceneTransform() const
void	scroll(qreal dx, qreal dy, const QRectF &rect = QRectF())
void	setAcceptDrops(bool on)
void	setAcceptHoverEvents(bool enabled)
void	setAcceptTouchEvents(bool enabled)
void	setAcceptedMouseButtons(Qt::MouseButtons buttons)
void	setActive(bool active)
void	setBoundingRegionGranularity(qreal granularity)
void	setCacheMode(QGraphicsItem::CacheMode mode, const QSize &logicalCacheSize = QSize())
void	setCursor(const QCursor &cursor)
void	setData(int key, const QVariant &value)
void	setEnabled(bool enabled)
void	setFiltersChildEvents(bool enabled)
void	setFlag(QGraphicsItem::GraphicsItemFlag flag, bool enabled = true)
void	setFlags(QGraphicsItem::GraphicsItemFlags flags)
void	setFocus(Qt::FocusReason focusReason = Qt::OtherFocusReason)
void	setFocusProxy(QGraphicsItem *item)
void	setGraphicsEffect(QGraphicsEffect *effect)
void	setGroup(QGraphicsItemGroup *group)
void	setInputMethodHints(Qt::InputMethodHints hints)
void	setOpacity(qreal opacity)
void	setPanelModality(QGraphicsItem::PanelModality panelModality)
void	setParentItem(QGraphicsItem *newParent)
void	setPos(const QPointF &pos)
void	setPos(qreal x, qreal y)
void	setRotation(qreal angle)
void	setScale(qreal factor)
void	setSelected(bool selected)
void	setToolTip(const QString &toolTip)
void	setTransform(const QTransform &matrix, bool combine = false)
void	setTransformOriginPoint(const QPointF &origin)
void	setTransformOriginPoint(qreal x, qreal y)
void	setTransformations(const QList<QGraphicsTransform > &transformations*)
void	setVisible(bool visible)
void	setX(qreal x)
void	setY(qreal y)
void	setZValue(qreal z)
virtual QPainterPath	shape() const
void	show()
void	stackBefore(const QGraphicsItem *sibling)
QGraphicsObject *	toGraphicsObject()
const QGraphicsObject *	toGraphicsObject() const
QString	toolTip() const
QGraphicsItem *	topLevelItem() const
QGraphicsWidget *	topLevelWidget() const
QTransform	transform() const
QPointF	transformOriginPoint() const
QList<QGraphicsTransform *>	transformations() const
virtual int	type() const
void	ungrabKeyboard()
void	ungrabMouse()
void	unsetCursor()
void	update(const QRectF &rect = QRectF())
void	update(qreal x, qreal y, qreal width, qreal height)
QGraphicsWidget *	window() const
qreal	x() const
qreal	y() const
qreal	zValue() const

【保护函数】

virtual void	contextMenuEvent(QGraphicsSceneContextMenuEvent *event)
virtual void	dragEnterEvent(QGraphicsSceneDragDropEvent *event)
virtual void	dragLeaveEvent(QGraphicsSceneDragDropEvent *event)
virtual void	dragMoveEvent(QGraphicsSceneDragDropEvent *event)
virtual void	dropEvent(QGraphicsSceneDragDropEvent *event)
virtual void	focusInEvent(QFocusEvent *event)
virtual void	focusOutEvent(QFocusEvent *event)
virtual void	hoverEnterEvent(QGraphicsSceneHoverEvent *event)
virtual void	hoverLeaveEvent(QGraphicsSceneHoverEvent *event)
virtual void	hoverMoveEvent(QGraphicsSceneHoverEvent *event)
virtual void	inputMethodEvent(QInputMethodEvent *event)
virtual QVariant	inputMethodQuery(Qt::InputMethodQuery query) const
virtual QVariant	itemChange(QGraphicsItem::GraphicsItemChange change, const QVariant &value)
virtual void	keyPressEvent(QKeyEvent *event)
virtual void	keyReleaseEvent(QKeyEvent *event)
virtual void	mouseDoubleClickEvent(QGraphicsSceneMouseEvent *event)
virtual void	mouseMoveEvent(QGraphicsSceneMouseEvent *event)
virtual void	mousePressEvent(QGraphicsSceneMouseEvent *event)
virtual void	mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
void	prepareGeometryChange()
virtual bool	sceneEvent(QEvent *event)
virtual bool	sceneEventFilter(QGraphicsItem *watched, QEvent *event)
void	updateMicroFocus()
virtual void	wheelEvent(QGraphicsSceneWheelEvent *event)