# QSize Class Reference

The QSize class defines the size of a two-dimensional object using integer point precision. More...

` #include <QSize>`

## Public Functions

QSize () | |

QSize ( int width, int height ) | |

QSize | boundedTo ( const QSize & otherSize ) const |

QSize | expandedTo ( const QSize & otherSize ) const |

int | height () const |

bool | isEmpty () const |

bool | isNull () const |

bool | isValid () const |

int & | rheight () |

int & | rwidth () |

void | scale ( int width, int height, Qt::AspectRatioMode mode ) |

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

void | setHeight ( int height ) |

void | setWidth ( int width ) |

void | transpose () |

int | width () const |

QSize & | operator*= ( qreal factor ) |

QSize & | operator+= ( const QSize & size ) |

QSize & | operator-= ( const QSize & size ) |

QSize & | operator/= ( qreal divisor ) |

## Related Non-Members

bool | operator!= ( const QSize & s1, const QSize & s2 ) |

const QSize | operator* ( const QSize & size, qreal factor ) |

const QSize | operator* ( qreal factor, const QSize & size ) |

const QSize | operator+ ( const QSize & s1, const QSize & s2 ) |

const QSize | operator- ( const QSize & s1, const QSize & s2 ) |

const QSize | operator/ ( const QSize & size, qreal divisor ) |

QDataStream & | operator<< ( QDataStream & stream, const QSize & size ) |

bool | operator== ( const QSize & s1, const QSize & s2 ) |

QDataStream & | operator>> ( QDataStream & stream, QSize & size ) |

## Detailed Description

The QSize class defines the size of a two-dimensional object using integer point precision.

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 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.

QSize objects can be streamed as well as compared.

**See also **QSizeF, QPoint, and QRect.

## Member Function Documentation

### QSize::QSize ()

Constructs a size with an invalid width and height (i.e., isValid() returns false).

**See also **isValid().

### QSize::QSize ( int *width*, int *height* )

Constructs a size with the given *width* and *height*.

**See also **setWidth() and setHeight().

### QSize QSize::boundedTo ( const QSize & *otherSize* ) const

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

**See also **expandedTo() and scale().

### QSize QSize::expandedTo ( const QSize & *otherSize* ) const

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

**See also **boundedTo() and scale().

### int QSize::height () const

Returns the height.

**See also **width() and setHeight().

### bool QSize::isEmpty () const

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

**See also **isNull() and isValid().

### bool QSize::isNull () const

Returns true if both the width and height is 0; otherwise returns false.

**See also **isValid() and isEmpty().

### bool QSize::isValid () const

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

**See also **isNull() and isEmpty().

### int & QSize::rheight ()

Returns a reference to the height.

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

QSize size(100, 10); size.rheight() += 5; // size becomes (100,15)

**See also **rwidth() and setHeight().

### int & QSize::rwidth ()

Returns a reference to the width.

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

QSize size(100, 10); size.rwidth() += 20; // size becomes (120,10)

**See also **rheight() and setWidth().

### void QSize::scale ( int *width*, int *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:

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

**See also **setWidth() and setHeight().

### void QSize::scale ( const QSize & *size*, Qt::AspectRatioMode *mode* )

This is an overloaded function.

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

### void QSize::setHeight ( int *height* )

Sets the height to the given *height*.

**See also **rheight(), height(), and setWidth().

### void QSize::setWidth ( int *width* )

Sets the width to the given *width*.

**See also **rwidth(), width(), and setHeight().

### void QSize::transpose ()

Swaps the width and height values.

**See also **setWidth() and setHeight().

### int QSize::width () const

Returns the width.

**See also **height() and setWidth().

### QSize & QSize::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.

Note that the result is rounded to the nearest integer.

**See also **scale().

### QSize & QSize::operator+= ( const QSize & *size* )

Adds the given *size* to *this* size, and returns a reference to this size. For example:

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

### QSize & QSize::operator-= ( const QSize & *size* )

Subtracts the given *size* from *this* size, and returns a reference to this size. For example:

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

### QSize & QSize::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.

Note that the result is rounded to the nearest integer.

**See also **QSize::scale().

## Related Non-Members

### bool operator!= ( const QSize & *s1*, const QSize & *s2* )

Returns true if *s1* and *s2* are different; otherwise returns false.

### const QSize operator* ( const QSize & *size*, qreal *factor* )

Multiplies the given *size* by the given *factor*, and returns the result rounded to the nearest integer.

**See also **QSize::scale().

### const QSize operator* ( qreal *factor*, const QSize & *size* )

This is an overloaded function.

Multiplies the given *size* by the given *factor*, and returns the result rounded to the nearest integer.

### const QSize operator+ ( const QSize & *s1*, const QSize & *s2* )

Returns the sum of *s1* and *s2*; each component is added separately.

### const QSize operator- ( const QSize & *s1*, const QSize & *s2* )

Returns *s2* subtracted from *s1*; each component is subtracted separately.

### const QSize operator/ ( const QSize & *size*, qreal *divisor* )

This is an overloaded function.

Divides the given *size* by the given *divisor*, and returns the result rounded to the nearest integer.

**See also **QSize::scale().

### QDataStream & operator<< ( QDataStream & *stream*, const QSize & *size* )

Writes the given *size* to the given *stream*, and returns a reference to the stream.

**See also **Serializing Qt Data Types.

### bool operator== ( const QSize & *s1*, const QSize & *s2* )

Returns true if *s1* and *s2* are equal; otherwise returns false.

### QDataStream & operator>> ( QDataStream & *stream*, QSize & *size* )

Reads a size from the given *stream* into the given *size*, and returns a reference to the stream.

**See also **Serializing Qt Data Types.

## No notes