QPolygonF Class

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

成员函数

QPolygonF::QPolygonF()

Constructs a polygon with no points.

参见 QVector::isEmpty().

QPolygonF::QPolygonF(int size)

Constructs a polygon of the given size. Creates an empty polygon if size == 0.

参见 QVector::isEmpty().

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

Constructs a polygon containing the specified points.

QPolygonF::QPolygonF(QVector<QPointF> &&v)

Default constructs an instance of QPolygonF.

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.

参见 isClosed().

QPolygonF::QPolygonF(const QPolygon &polygon)

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

参见 toPolygon().

QPolygonF::QPolygonF(const QPolygonF &polygon)

Constructs a copy of the given polygon.

QPolygonF::QPolygonF(QPolygonF &&other)

Move-copy constructor.

QPolygonF::~QPolygonF()

Destroys the polygon.

QRectF QPolygonF::boundingRect() const

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

参见 QVector::isEmpty().

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

Returns true if the given point is inside the polygon according to the specified fillRule; otherwise returns false.

This function was introduced in Qt 4.3.

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.

This function was introduced in Qt 4.3.

bool QPolygonF::isClosed() const

Returns 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.

参见 QVector::first() and QVector::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.

This function was introduced in Qt 4.3.

void QPolygonF::swap(QPolygonF &other)

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

This function was introduced in Qt 4.8.

QPolygon QPolygonF::toPolygon() const

Creates and returns a QPolygon by converting each QPointF to a QPoint.

参见 QPointF::toPoint().

void QPolygonF::translate(const QPointF &offset)

Translate all points in the polygon by the given offset.

参见 translated().

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

This is an overloaded function.

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

参见 translated().

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

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

This function was introduced in Qt 4.6.

参见 translate().

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

This is an overloaded function.

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

This function was introduced in Qt 4.6.

参见 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.

This function was introduced in Qt 4.3.

参见 intersected() and subtracted().

QPolygonF::operator QVariant() const

Returns the polygon as a QVariant.

QPolygonF &QPolygonF::operator=(QPolygonF &&other)

Move-assignment operator.

QPolygonF &QPolygonF::operator=(const QPolygonF &other)

Copy-assignment operator.