QSizeF Class▲
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Header: QSizeF
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CMake:
find_package(Qt6 REQUIRED COMPONENTS Core)
target_link_libraries(mytarget PRIVATE Qt6::Core)
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qmake: QT += core
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Group: QSizeF is part of painting
Detailed Description▲
A size is specified by a width() and a height(). It can be set in the constructor and changed using the setWidth(), setHeight(), or scale() functions, or using arithmetic operators. A size can also be manipulated directly by retrieving references to the width and height using the rwidth() and rheight() functions. Finally, the width and height can be swapped using the transpose() function.
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() function returns true if either of the width and height is less than (or equal to) zero, while the isNull() function returns true only if both the width and the height is zero.
Use the expandedTo() function to retrieve a size which holds the maximum height and width of this size and a given size. Similarly, the boundedTo() function returns a size which holds the minimum height and width of this size and a given size.
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.
See Also▲
Member Function Documentation▲
[constexpr, since 5.14] QSizeF QSizeF::grownBy(QMarginsF margins) const▲
Returns the size that results from growing this size by margins.
This function was introduced in Qt 5.14.
See Also▲
See also shrunkBy()
[constexpr, since 5.14] QSizeF QSizeF::shrunkBy(QMarginsF margins) const▲
Returns the size that results from shrinking this size by margins.
This function was introduced in Qt 5.14.
See Also▲
See also grownBy()
[constexpr] QSizeF::QSizeF()▲
[constexpr] QSizeF::QSizeF(const QSize &size)▲
Constructs a size with floating point accuracy from the given size.
See Also▲
See also toSize(), QSize::toSizeF()
[constexpr] QSizeF::QSizeF(qreal width, qreal height)▲
Constructs a size with the given finite width and height.
[constexpr] QSizeF QSizeF::boundedTo(const QSizeF &otherSize) const▲
Returns a size holding the minimum width and height of this size and the given otherSize.
See Also▲
See also expandedTo(), scale()
[constexpr] QSizeF QSizeF::expandedTo(const QSizeF &otherSize) const▲
Returns a size holding the maximum width and height of this size and the given otherSize.
See Also▲
[static, since 5.8] QSizeF QSizeF::fromCGSize(CGSize size)▲
[constexpr] qreal QSizeF::height() const▲
[constexpr] bool QSizeF::isEmpty() const▲
Returns true if either of the width and height is less than or equal to 0; otherwise returns false.
See Also▲
bool QSizeF::isNull() const▲
Returns true if both the width and height are 0.0 (ignoring the sign); otherwise returns false.
See Also▲
[constexpr] bool QSizeF::isValid() const▲
Returns true if both the width and height are equal to or greater than 0; otherwise returns false.
See Also▲
[constexpr] 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)See Also▲
[constexpr] 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)See Also▲
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.
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If mode is Qt::IgnoreAspectRatio, the size is set to (width, height).
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If mode is Qt::KeepAspectRatio, the current size is scaled to a rectangle as large as possible inside (width, height), preserving the aspect ratio.
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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)See Also▲
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.
[since 5.0] 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.
See Also▲
See also scale()
[since 5.0] 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.
[constexpr] void QSizeF::setHeight(qreal height)▲
[constexpr] void QSizeF::setWidth(qreal width)▲
[since 5.8] CGSize QSizeF::toCGSize() const▲
Creates a CGSize from a QSizeF.
This function was introduced in Qt 5.8.
See Also▲
See also fromCGSize()
[constexpr] 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.
See Also▲
See also QSizeF(), QSize::toSizeF()
void QSizeF::transpose()▲
[constexpr, since 5.0] QSizeF QSizeF::transposed() const▲
Returns the size with width and height values swapped.
This function was introduced in Qt 5.0.
See Also▲
See also transpose()
[constexpr] qreal QSizeF::width() const▲
[constexpr] QSizeF &QSizeF::operator*=(qreal factor)▲
This is an overloaded function.
Multiplies both the width and height by the given finite factor and returns a reference to the size.
See Also▲
See also scale()
[constexpr] 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)[constexpr] 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)▲
Related Non-Members▲
[constexpr] bool operator!=(const QSizeF &s1, const QSizeF &s2)▲
Returns true if s1 and s2 are sufficiently different; otherwise returns false.
This function does not check for strict inequality; instead, it uses a fuzzy comparison to compare the sizes' extents.
[constexpr] QSizeF operator*(const QSizeF &size, qreal factor)▲
This is an overloaded function.
Multiplies the given size by the given finite factor and returns the result.
See Also▲
See also QSizeF::scale()
[constexpr] QSizeF operator*(qreal factor, const QSizeF &size)▲
This is an overloaded function.
Multiplies the given size by the given finite factor and returns the result.
[constexpr] QSizeF operator+(const QSizeF &s1, const QSizeF &s2)▲
Returns the sum of s1 and s2; each component is added separately.
[constexpr] QSizeF operator-(const QSizeF &s1, const QSizeF &s2)▲
Returns s2 subtracted from s1; each component is subtracted separately.
QSizeF operator/(const QSizeF &size, qreal divisor)▲
This is an overloaded function.
Divides the given size by the given divisor and returns the result. The divisor must not be either zero or NaN.
See Also▲
See also QSizeF::scale()
QDataStream &operator<<(QDataStream &stream, const QSizeF &size)▲
Writes the given size to the given stream and returns a reference to the stream.
See Also▲
See also Serializing Qt Data Types
[constexpr] bool operator==(const QSizeF &s1, const QSizeF &s2)▲
Returns true if s1 and s2 are approximately equal; otherwise returns false.
This function does not check for strict equality; instead, it uses a fuzzy comparison to compare the sizes' extents.
See Also▲
See also qFuzzyCompare
QDataStream &operator>>(QDataStream &stream, QSizeF &size)▲
Reads a size from the given stream into the given size and returns a reference to the stream.
See Also▲
See also Serializing Qt Data Types