QPolygonF 类

QPolygonF 类提供使用浮点精度的点列表。 更多...

头：	#include <QPolygonF>
CMake:	find_package(Qt6 REQUIRED COMPONENTS Gui) target_link_libraries(mytarget PRIVATE Qt6::Gui)
qmake:	QT += gui
继承：	QList

• 所有成员列表，包括继承成员
• QPolygonF is part of 描绘类 and 隐式共享类 .

注意： 此类的所有函数 可重入 .

公共函数

	QPolygonF ()
	QPolygonF (const QList<QPointF> & points )
	QPolygonF (const QRectF & rectangle )
	QPolygonF (const QPolygon & polygon )
QRectF	boundingRect () const
bool	containsPoint (const QPointF & point , Qt::FillRule fillRule ) const
QPolygonF	intersected (const QPolygonF & r ) const
bool	intersects (const QPolygonF & p ) const
bool	isClosed () const
QPolygonF	subtracted (const QPolygonF & r ) const
void	swap (QPolygonF & other )
QPolygon	toPolygon () const
void	translate (const QPointF & offset )
void	translate (qreal dx , qreal dy )
QPolygonF	translated (const QPointF & offset ) const
QPolygonF	translated (qreal dx , qreal dy ) const
QPolygonF	united (const QPolygonF & r ) const
QVariant	operator QVariant () const

相关非成员

QDataStream &	operator<< (QDataStream & stream , const QPolygonF & polygon )
QDataStream &	operator>> (QDataStream & stream , QPolygonF & polygon )

详细描述

A QPolygonF is a QList < QPointF >. The easiest way to add points to a QPolygonF is to use its streaming operator, as illustrated below:

QPolygonF polygon;
polygon << QPointF(10.4, 20.5) << QPointF(20.2, 30.2);
					

In addition to the functions provided by QList , QPolygonF provides the boundingRect () 和 translate () functions for geometry operations. Use the QTransform::map () function for more general transformations of QPolygonFs.

QPolygonF also provides the isClosed () function to determine whether a polygon's start and end points are the same, and the toPolygon () function returning an integer precision copy of this polygon.

The QPolygonF class is 隐式共享 .

另请参阅 QList , QPolygon ，和 QLineF .

成员函数文档编制

[constexpr noexcept] QPolygonF:: QPolygonF ()

Constructs a polygon with no points.

另请参阅 QList::isEmpty ().

QPolygonF:: QPolygonF (const QList < QPointF > & points )

Constructs a polygon containing the specified points .

QPolygonF:: QPolygonF (const QRectF & rectangle )

Constructs a closed polygon from the specified rectangle .

The polygon contains the four vertices of the rectangle in clockwise order starting and ending with the top-left vertex.

另请参阅 isClosed ().

QPolygonF:: QPolygonF (const QPolygon & polygon )

Constructs a float based polygon from the specified integer based polygon .

另请参阅 toPolygon ().

QRectF QPolygonF:: boundingRect () const

Returns the bounding rectangle of the polygon, or QRectF (0,0,0,0) if the polygon is empty.

另请参阅 QList::isEmpty ().

bool QPolygonF:: containsPoint (const QPointF & point , Qt::FillRule fillRule ) const

返回 true 若给定 point is inside the polygon according to the specified fillRule ；否则返回 false .

QPolygonF QPolygonF:: intersected (const QPolygonF & r ) const

Returns a polygon which is the intersection of this polygon and r .

Set operations on polygons will treat the polygons as areas. Non-closed polygons will be treated as implicitly closed.

另请参阅 intersects ().

bool QPolygonF:: intersects (const QPolygonF & p ) const

返回 true if the current polygon intersects at any point the given polygon p 。也返回 true if the current polygon contains or is contained by any part of p .

Set operations on polygons will treat the polygons as areas. Non-closed polygons will be treated as implicitly closed.

另请参阅 intersected ().

bool QPolygonF:: isClosed () const

返回 true if the polygon is closed; otherwise returns false .

A polygon is said to be closed if its start point and end point are equal.

另请参阅 QList::first () 和 QList::last ().

QPolygonF QPolygonF:: subtracted (const QPolygonF & r ) const

Returns a polygon which is r subtracted from this polygon.

Set operations on polygons will treat the polygons as areas. Non-closed polygons will be treated as implicitly closed.

void QPolygonF:: swap ( QPolygonF & other )

Swaps polygon other with this polygon. This operation is very fast and never fails.

QPolygon QPolygonF:: toPolygon () const

创建并返回 QPolygon by converting each QPointF 到 QPoint .

另请参阅 QPointF::toPoint ().

void QPolygonF:: translate (const QPointF & offset )

Translate all points in the polygon by the given offset .

另请参阅 translated ().

void QPolygonF:: translate ( qreal dx , qreal dy )

这是重载函数。

Translates all points in the polygon by ( dx , dy ).

另请参阅 translated ().

QPolygonF QPolygonF:: translated (const QPointF & offset ) const

Returns a copy of the polygon that is translated by the given offset .

另请参阅 translate ().

QPolygonF QPolygonF:: translated ( qreal dx , qreal dy ) const

这是重载函数。

Returns a copy of the polygon that is translated by ( dx , dy ).

另请参阅 translate ().

QPolygonF QPolygonF:: united (const QPolygonF & r ) const

Returns a polygon which is the union of this polygon and r .

Set operations on polygons will treat the polygons as areas. Non-closed polygons will be treated as implicitly closed.

另请参阅 intersected () 和 subtracted ().

QVariant QPolygonF:: operator QVariant () const

Returns the polygon as a QVariant .

相关非成员

QDataStream & operator<< ( QDataStream & stream , const QPolygonF & polygon )

写入给定 polygon 到给定 stream ，并返回流引用。

另请参阅 序列化 Qt 数据类型 .

QDataStream & operator>> ( QDataStream & stream , QPolygonF & polygon )

Reads a polygon from the given stream 进给定 polygon ，并返回流引用。

另请参阅 序列化 Qt 数据类型 .

内容

• 公共函数

• 相关非成员

• 详细描述