QSize Class Reference

The QSize class defines the size of a two-dimensional object. More...

#include <qsize.h>

List of all member functions.

Public Members

enum ScaleMode { ScaleFree, ScaleMin, ScaleMax }
QSize ()
QSize ( int w, int h )
bool isNull () const
bool isEmpty () const
bool isValid () const
int width () const
int height () const
void setWidth ( int w )
void setHeight ( int h )
void transpose ()
void scale ( int w, int h, ScaleMode mode )
void scale ( const QSize & s, ScaleMode mode )
QSize expandedTo ( const QSize & otherSize ) const
QSize boundedTo ( const QSize & otherSize ) const
QCOORD & rwidth ()
QCOORD & rheight ()
QSize & operator+= ( const QSize & s )
QSize & operator-= ( const QSize & s )
QSize & operator*= ( int c )
QSize & operator*= ( double c )
QSize & operator/= ( int c )
QSize & operator/= ( double c )

Related Functions

bool operator== ( const QSize & s1, const QSize & s2 )
bool operator!= ( const QSize & s1, const QSize & s2 )
const QSize operator+ ( const QSize & s1, const QSize & s2 )
const QSize operator- ( const QSize & s1, const QSize & s2 )
const QSize operator* ( const QSize & s, int c )
const QSize operator* ( int c, const QSize & s )
const QSize operator* ( const QSize & s, double c )
const QSize operator* ( double c, const QSize & s )
const QSize operator/ ( const QSize & s, int c )
const QSize operator/ ( const QSize & s, double c )
QDataStream & operator<< ( QDataStream & s, const QSize & sz )
QDataStream & operator>> ( QDataStream & s, QSize & sz )

Detailed Description

The QSize class defines the size of a two-dimensional object.

A size is specified by a width and a height.

The coordinate type is QCOORD (defined in <qwindowdefs.h> as int). The minimum value of QCOORD is QCOORD_MIN (-2147483648) and the maximum value is QCOORD_MAX (2147483647).

The size can be set in the constructor and changed with setWidth() and setHeight(), or using operator+=(), operator-=(), operator*=() and operator/=(), etc. You can swap the width and height with transpose(). You can get a size which holds the maximum height and width of two sizes using expandedTo(), and the minimum height and width of two sizes using boundedTo().

Member Type Documentation

QSize::ScaleMode

This enum type defines the different ways of scaling a size.

QSize::ScaleFree - The size is scaled freely. The ratio is not preserved.
QSize::ScaleMin - The size is scaled to a rectangle as large as possible inside a given rectangle, preserving the aspect ratio.
QSize::ScaleMax - The size is scaled to a rectangle as small as possible outside a given rectangle, preserving the aspect ratio.

See also QSize::scale(), QImage::scale(), and QImage::smoothScale().

Member Function Documentation

QSize::QSize ()

Constructs a size with invalid (negative) width and height.

QSize::QSize ( int w, int h )

Constructs a size with width w and height h.

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

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

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

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

Examples: customlayout/card.cpp and customlayout/flow.cpp.

int QSize::height () const

Returns the height.

bool QSize::isEmpty () const

Returns TRUE if the width is <= 0 or the height is <= 0, otherwise FALSE.

bool QSize::isNull () const

Returns TRUE if the width is 0 and the height is 0; otherwise returns FALSE.

bool QSize::isValid () const

Returns TRUE if the width is equal to or greater than 0 and the height is equal to or greater than 0; otherwise returns FALSE.

QSize & QSize::operator*= ( int c )

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

QSize & QSize::operator*= ( double c )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

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

Note that the result is truncated.

QSize & QSize::operator+= ( const QSize & s )

Adds s to the size and returns a reference to this size.

Example:

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

QSize & QSize::operator-= ( const QSize & s )

Subtracts s from the size and returns a reference to this size.

Example:

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

QSize & QSize::operator/= ( int c )

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

QSize & QSize::operator/= ( double c )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

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

Note that the result is truncated.

QCOORD & QSize::rheight ()

Returns a reference to the height.

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

Example:

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

QCOORD & QSize::rwidth ()

Returns a reference to the width.

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

Example:

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

void QSize::scale ( int w, int h, ScaleMode mode )

Scales the size to a rectangle of width w and height h according to the ScaleMode mode.

If mode is ScaleFree, the size is set to (w, h).
If mode is ScaleMin, the current size is scaled to a rectangle as large as possible inside (w, h), preserving the aspect ratio.
If mode is ScaleMax, the current size is scaled to a rectangle as small as possible outside (w, h), preserving the aspect ratio.

Example:

    QSize t1( 10, 12 );
    t1.scale( 60, 60, QSize::ScaleFree );
    // t1 is (60, 60)

    QSize t2( 10, 12 );
    t2.scale( 60, 60, QSize::ScaleMin );
    // t2 is (50, 60)

    QSize t3( 10, 12 );
    t3.scale( 60, 60, QSize::ScaleMax );
    // t3 is (60, 72)

void QSize::scale ( const QSize & s, ScaleMode mode )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Equivalent to scale(s.width(), s.height(), mode).

void QSize::setHeight ( int h )

Sets the height to h.

void QSize::setWidth ( int w )

Sets the width to w.

void QSize::transpose ()

Swaps the values of width and height.

int QSize::width () const

Returns the width.

Related Functions

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

Returns TRUE if s1 and s2 are different; otherwise returns FALSE.

const QSize operator* ( const QSize & s, int c )

Multiplies s by c and returns the result.

const QSize operator* ( int c, const QSize & s )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Multiplies s by c and returns the result.

const QSize operator* ( const QSize & s, double c )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Multiplies s by c and returns the result.

const QSize operator* ( double c, const QSize & s )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Multiplies s by c and returns the result.

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 & s, int c )

Divides s by c and returns the result.

const QSize operator/ ( const QSize & s, double c )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Divides s by c and returns the result.

Note that the result is truncated.

QDataStream & operator<< ( QDataStream & s, const QSize & sz )

Writes the size sz to the stream s and returns a reference to the stream.

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

Returns TRUE if s1 and s2 are equal; otherwise returns FALSE.

QDataStream & operator>> ( QDataStream & s, QSize & sz )

Reads the size from the stream s into size sz and returns a reference to the stream.

Trademarks

Qt version 3.2.0b2