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QSizeF 类

QSizeF 类使用浮点精度定义 2D 对象的大小。 更多...

头： #include <QSizeF>
CMake: find_package(Qt6 REQUIRED COMPONENTS Core)
target_link_libraries(mytarget PRIVATE Qt6::Core)
qmake: QT += core

公共函数

QSizeF ()
QSizeF (const QSize & size )
QSizeF (qreal width , qreal height )
QSizeF boundedTo (const QSizeF & otherSize ) const
QSizeF expandedTo (const QSizeF & otherSize ) const
QSizeF grownBy (QMarginsF margins ) const
qreal height () const
bool isEmpty () const
bool isNull () const
bool isValid () const
qreal & rheight ()
qreal & rwidth ()
void scale (qreal width , qreal height , Qt::AspectRatioMode mode )
void scale (const QSizeF & size , Qt::AspectRatioMode mode )
QSizeF scaled (qreal width , qreal height , Qt::AspectRatioMode mode ) const
QSizeF scaled (const QSizeF & s , Qt::AspectRatioMode mode ) const
void setHeight (qreal height )
void setWidth (qreal width )
QSizeF shrunkBy (QMarginsF margins ) const
CGSize toCGSize () const
QSize toSize () const
void transpose ()
QSizeF transposed () const
qreal width () const
QSizeF & operator*= (qreal factor )
QSizeF & operator+= (const QSizeF & size )
QSizeF & operator-= (const QSizeF & size )
QSizeF & operator/= (qreal divisor )

静态公共成员

QSizeF fromCGSize (CGSize size )
bool operator!= (const QSizeF & s1 , const QSizeF & s2 )
QSizeF operator* (const QSizeF & size , qreal factor )
QSizeF operator* (qreal factor , const QSizeF & size )
QSizeF operator+ (const QSizeF & s1 , const QSizeF & s2 )
QSizeF operator- (const QSizeF & s1 , const QSizeF & s2 )
QSizeF operator/ (const QSizeF & size , qreal divisor )
QDataStream & operator<< (QDataStream & stream , const QSizeF & size )
bool operator== (const QSizeF & s1 , const QSizeF & s2 )
QDataStream & operator>> (QDataStream & stream , QSizeF & size )

详细描述

大小的指定是通过 width () 和 height ()。可以在构造函数中设置它和改变使用 setWidth (), setHeight ()，或 scale () 函数，或使用算术运算符。也可以直接操纵尺寸通过检索宽度和高度的引用使用 rwidth () 和 rheight () 函数。最后，可以交换宽度和高度使用 transpose () 函数。

The isValid () function determines if a size is valid. A valid size has both width and height greater than or equal to zero. The isEmpty () 函数返回 true if either of the width and height is less than (or equal to) zero, while the isNull () 函数返回 true 仅当宽度和高度两者为 0 时。

使用 expandedTo () function to retrieve a size which holds the maximum height and width of this size and a given size. Similarly, the boundedTo () 函数返回由此尺寸和给定尺寸保持的最小高度 宽度的尺寸。

The QSizeF class also provides the toSize () function returning a QSize copy of this size, constructed by rounding the width and height to the nearest integers.

QSizeF objects can be streamed as well as compared.

另请参阅 QSize , QPointF ，和 QRectF .

成员函数文档编制

[constexpr noexcept] QSizeF QSizeF:: grownBy ( QMarginsF margins ) const

返回尺寸产生自此尺寸的增长按 margins .

另请参阅 shrunkBy ().

[constexpr noexcept] QSizeF QSizeF:: shrunkBy ( QMarginsF margins ) const

返回尺寸产生从此尺寸的收缩按 margins .

另请参阅 grownBy ().

[constexpr noexcept] QSizeF:: QSizeF ()

Constructs an invalid size.

另请参阅 isValid ().

[constexpr noexcept] QSizeF:: QSizeF (const QSize & size )

Constructs a size with floating point accuracy from the given size .

另请参阅 toSize () 和 QSize::toSizeF ().

[constexpr noexcept] QSizeF:: QSizeF ( qreal width , qreal height )

Constructs a size with the given finite width and height .

[constexpr noexcept] QSizeF QSizeF:: boundedTo (const QSizeF & otherSize ) const

返回尺寸，该尺寸保持最小宽度 高度，及给定 otherSize .

另请参阅 expandedTo () 和 scale ().

[constexpr noexcept] QSizeF QSizeF:: expandedTo (const QSizeF & otherSize ) const

返回的尺寸保持此尺寸的最大宽度 高度和给定 otherSize .

另请参阅 boundedTo () 和 scale ().

[static noexcept] QSizeF QSizeF:: fromCGSize ( CGSize size )

创建 QRectF from size .

另请参阅 toCGSize ().

[constexpr noexcept] qreal QSizeF:: height () const

返回高度。

另请参阅 width () 和 setHeight ().

[constexpr noexcept] bool QSizeF:: isEmpty () const

返回 true 若宽度和高度两者任一 <= 0；否则返回 false .

另请参阅 isNull () 和 isValid ().

[noexcept] bool QSizeF:: isNull () const

返回 true 若宽度和高度两者为 0.0 (忽略正负号)；否则返回 false .

另请参阅 isValid () 和 isEmpty ().

[constexpr noexcept] bool QSizeF:: isValid () const

返回 true if both the width and height are equal to or greater than 0; otherwise returns false .

另请参阅 isNull () 和 isEmpty ().

[constexpr noexcept] qreal &QSizeF:: rheight ()

返回高度的引用。

使用引用使直接操纵高度成为可能。例如： 

QSizeF size(100, 10.2);
size.rheight() += 5.5;
// size becomes (100,15.7)

另请参阅 rwidth () 和 setHeight ().

[constexpr noexcept] qreal &QSizeF:: rwidth ()

返回宽度的引用。

使用引用使直接操纵宽度成为可能。例如： 

QSizeF size(100.3, 10);
size.rwidth() += 20.5;
 // size becomes (120.8,10)

另请参阅 rheight () 和 setWidth ().

[noexcept] void QSizeF:: scale ( qreal width , qreal height , Qt::AspectRatioMode mode )

把尺寸比例缩放到矩形采用给定 width and height ，根据指定 mode .

  • 若 mode is Qt::IgnoreAspectRatio ，尺寸被设为 ( width , height ).
  • 若 mode is Qt::KeepAspectRatio , the current size is scaled to a rectangle as large as possible inside ( width , height ), preserving the aspect ratio.
  • 若 mode is Qt::KeepAspectRatioByExpanding , the current size is scaled to a rectangle as small as possible outside ( width , height ), preserving the aspect ratio.

范例： 

QSizeF t1(10, 12);
t1.scale(60, 60, Qt::IgnoreAspectRatio);
// t1 is (60, 60)
QSizeF t2(10, 12);
t2.scale(60, 60, Qt::KeepAspectRatio);
// t2 is (50, 60)
QSizeF t3(10, 12);
t3.scale(60, 60, Qt::KeepAspectRatioByExpanding);
// t3 is (60, 72)

另请参阅 setWidth (), setHeight ()，和 scaled ().

[noexcept] void QSizeF:: scale (const QSizeF & size , Qt::AspectRatioMode mode )

这是重载函数。

把尺寸比例缩放到矩形采用给定 size ，根据指定 mode .

[noexcept] QSizeF QSizeF:: scaled ( qreal width , qreal height , Qt::AspectRatioMode mode ) const

Returns a size scaled to a rectangle with the given width and height ，根据指定 mode .

另请参阅 scale ().

[noexcept] QSizeF QSizeF:: scaled (const QSizeF & s , Qt::AspectRatioMode mode ) const

这是重载函数。

Returns a size scaled to a rectangle with the given size s ，根据指定 mode .

[constexpr noexcept] void QSizeF:: setHeight ( qreal height )

Sets the height to the given finite height .

另请参阅 height (), rheight ()，和 setWidth ().

[constexpr noexcept] void QSizeF:: setWidth ( qreal width )

Sets the width to the given finite width .

另请参阅 width (), rwidth ()，和 setHeight ().

[noexcept] CGSize QSizeF:: toCGSize () const

创建 CGSize 从 QSizeF .

另请参阅 fromCGSize ().

[constexpr noexcept] QSize QSizeF:: toSize () const

Returns an integer based copy of this size.

Note that the coordinates in the returned size will be rounded to the nearest integer.

另请参阅 QSizeF () 和 QSize::toSizeF ().

[noexcept] void QSizeF:: transpose ()

交换宽度和高度值。

另请参阅 setWidth (), setHeight ()，和 transposed ().

[constexpr noexcept] QSizeF QSizeF:: transposed () const

Returns the size with width and height values swapped.

另请参阅 transpose ().

[constexpr noexcept] qreal QSizeF:: width () const

返回宽度。

另请参阅 height () 和 setWidth ().

[constexpr noexcept] QSizeF &QSizeF:: operator*= ( qreal factor )

这是重载函数。

Multiplies both the width and height by the given finite factor and returns a reference to the size.

另请参阅 scale ().

[constexpr noexcept] QSizeF &QSizeF:: operator+= (const QSizeF & size )

添加给定 size to this size and returns a reference to this size. For example: 

QSizeF s( 3, 7);
QSizeF r(-1, 4);
s += r;
// s becomes (2,11)

[constexpr noexcept] QSizeF &QSizeF:: operator-= (const QSizeF & size )

减去给定 size from this size and returns a reference to this size. For example: 

QSizeF s( 3, 7);
QSizeF r(-1, 4);
s -= r;
// s becomes (4,3)

QSizeF &QSizeF:: operator/= ( qreal divisor )

这是重载函数。

Divides both the width and height by the given divisor and returns a reference to the size. The divisor must not be either zero or NaN.

另请参阅 scale ().

相关非成员

[constexpr] bool operator!= (const QSizeF & s1 , const QSizeF & s2 )

返回 true if s1 and s2 are sufficiently different; otherwise returns false .

警告： This function does not check for strict inequality; instead, it uses a fuzzy comparison to compare the sizes' extents.

[constexpr noexcept] QSizeF operator* (const QSizeF & size , qreal factor )

这是重载函数。

乘以给定 size by the given finite factor and returns the result.

另请参阅 QSizeF::scale ().

[constexpr noexcept] QSizeF operator* ( qreal factor , const QSizeF & size )

这是重载函数。

乘以给定 size by the given finite factor and returns the result.

[constexpr noexcept] QSizeF operator+ (const QSizeF & s1 , const QSizeF & s2 )

Returns the sum of s1 and s2 ；分别相加各分量。

[constexpr noexcept] QSizeF operator- (const QSizeF & s1 , const QSizeF & s2 )

返回 s2 减去 s1 ；分别减去各分量。

QSizeF operator/ (const QSizeF & size , qreal divisor )

这是重载函数。

除以给定 size 通过给定 divisor and returns the result. The divisor must not be either zero or NaN.

另请参阅 QSizeF::scale ().

QDataStream & operator<< ( QDataStream & stream , const QSizeF & size )

写入给定 size 到给定 stream 并返回流引用。

另请参阅 序列化 Qt 数据类型 .

[constexpr] bool operator== (const QSizeF & s1 , const QSizeF & s2 )

返回 true if s1 and s2 are approximately equal; otherwise returns false.

警告： This function does not check for strict equality; instead, it uses a fuzzy comparison to compare the sizes' extents.

另请参阅 qFuzzyCompare .

QDataStream & operator>> ( QDataStream & stream , QSizeF & size )

读取大小从给定 stream 进给定 size 并返回流引用。

另请参阅 序列化 Qt 数据类型 .

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