QSizeF Class

成员函数

QSizeF::QSizeF()

Constructs an invalid size.

参见 isValid().

QSizeF::QSizeF(const QSize &size)

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

参见 toSize().

QSizeF::QSizeF(qreal width, qreal height)

Constructs a size with the given width and height.

QSizeF QSizeF::boundedTo(const QSizeF &otherSize) const

Returns a size holding the minimum width and height of this size and the given otherSize.

参见 expandedTo() and scale().

QSizeF QSizeF::expandedTo(const QSizeF &otherSize) const

Returns a size holding the maximum width and height of this size and the given otherSize.

参见 boundedTo() and scale().

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

Creates a QRectF from size.

This function was introduced in Qt 5.8.

参见 toCGSize().

qreal QSizeF::height() const

Returns the height.

参见 width() and setHeight().

bool QSizeF::isEmpty() const

Returns true if either of the width and height is less than or equal to 0; otherwise returns false.

参见 isNull() and isValid().

bool QSizeF::isNull() const

Returns true if both the width and height are 0.0 (ignoring the sign); otherwise returns false.

参见 isValid() and isEmpty().

bool QSizeF::isValid() const

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

参见 isNull() and isEmpty().

qreal &QSizeF::rheight()

Returns a reference to the height.

Using a reference makes it possible to manipulate the height directly. For example:

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

  // size becomes (100,15.7)

参见 rwidth() and setHeight().

qreal &QSizeF::rwidth()

Returns a reference to the width.

Using a reference makes it possible to manipulate the width directly. For example:

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

   // size becomes (120.8,10)

参见 rheight() and setWidth().

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

Scales the size to a rectangle with the given width and height, according to the specified mode.

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

Example:

  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)

参见 setWidth(), setHeight(), and scaled().

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

This is an overloaded function.

Scales the size to a rectangle with the given size, according to the specified mode.

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

Returns a size scaled to a rectangle with the given width and height, according to the specified mode.

This function was introduced in Qt 5.0.

参见 scale().

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

This is an overloaded function.

Returns a size scaled to a rectangle with the given size s, according to the specified mode.

This function was introduced in Qt 5.0.

void QSizeF::setHeight(qreal height)

Sets the height to the given height.

参见 height(), rheight(), and setWidth().

void QSizeF::setWidth(qreal width)

Sets the width to the given width.

参见 width(), rwidth(), and setHeight().

CGSize QSizeF::toCGSize() const

Creates a CGSize from a QSizeF.

This function was introduced in Qt 5.8.

参见 fromCGSize().

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.

参见 QSizeF().

void QSizeF::transpose()

Swaps the width and height values.

参见 setWidth(), setHeight(), and transposed().

QSizeF QSizeF::transposed() const

Returns the size with width and height values swapped.

This function was introduced in Qt 5.0.

参见 transpose().

qreal QSizeF::width() const

Returns the width.

参见 height() and setWidth().

QSizeF &QSizeF::operator*=(qreal factor)

This is an overloaded function.

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

参见 scale().

QSizeF &QSizeF::operator+=(const QSizeF &size)

Adds the given 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)

QSizeF &QSizeF::operator-=(const QSizeF &size)

Subtracts the given 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)

This is an overloaded function.

Divides both the width and height by the given divisor and returns a reference to the size.

参见 scale().