# QwtScaleMap Class Reference

A scale map. More...

`#include <qwt_scale_map.h>`

List of all members.

## Public Member Functions

double | invTransform (double p) const
bool | isInverting () const
QwtScaleMap & | operator= (const QwtScaleMap &)
double | p1 () const
double | p2 () const
double | pDist () const
| QwtScaleMap (const QwtScaleMap &)
| QwtScaleMap ()
double | s1 () const
double | s2 () const
double | sDist () const
void | setPaintInterval (double p1, double p2)
void | setScaleInterval (double s1, double s2)
void | setTransformation (QwtScaleTransformation *)
double | transform (double s) const
const QwtScaleTransformation * | transformation () const
| ~QwtScaleMap ()

## Static Public Member Functions

static QRectF | invTransform (const QwtScaleMap &, const QwtScaleMap &, const QRectF &)
static QPointF | invTransform (const QwtScaleMap &, const QwtScaleMap &, const QPointF &)
static QPointF | transform (const QwtScaleMap &, const QwtScaleMap &, const QPointF &)
static QRectF | transform (const QwtScaleMap &, const QwtScaleMap &, const QRectF &)

## Public Attributes

QT_STATIC_CONST double | LogMax = 1.0e150
QT_STATIC_CONST double | LogMin = 1.0e-150

## Detailed Description

A scale map.

QwtScaleMap offers transformations from the coordinate system of a scale into the linear coordinate system of a paint device and vice versa.

## Constructor & Destructor Documentation

QwtScaleMap::QwtScaleMap | ( |  | ) |

Constructor.

The scale and paint device intervals are both set to [0,1].

QwtScaleMap::QwtScaleMap | ( | const QwtScaleMap & | other | ) |

Copy constructor.

QwtScaleMap::~QwtScaleMap | ( |  | ) |

Destructor

## Member Function Documentation

double QwtScaleMap::invTransform | ( | double | p | ) | const`[inline]`

Transform an paint device value into a value in the interval of the scale.

Parameters:

  p | Value relative to the coordinates of the paint device

See also:
  transform()

QPointF QwtScaleMap::invTransform | ( | const QwtScaleMap & | xMap,
|  | const QwtScaleMap & | yMap,
|  | const QPointF & | pos
| ) |  | `[static]`

Transform a rectangle from paint to scale coordinates

Parameters:

  xMap | X map
  yMap | Y map
  pos | Position in paint coordinates

Returns:
  Position in scale coordinates

See also:
  transform()

QRectF QwtScaleMap::invTransform | ( | const QwtScaleMap & | xMap,
|  | const QwtScaleMap & | yMap,
|  | const QRectF & | rect
| ) |  | `[static]`

Transform a rectangle from paint to scale coordinates

Parameters:

  xMap | X map
  yMap | Y map
  rect | Rectangle in paint coordinates

Returns:
  Rectangle in scale coordinates

See also:
  transform()

bool QwtScaleMap::isInverting | ( |  | ) | const`[inline]`

Returns:
  True, when ( p1() < p2() ) != ( s1() < s2() )

QwtScaleMap & QwtScaleMap::operator= | ( | const QwtScaleMap & | other | ) |

Assignment operator.

double QwtScaleMap::p1 | ( |  | ) | const`[inline]`

Returns:
  First border of the paint interval

double QwtScaleMap::p2 | ( |  | ) | const`[inline]`

Returns:
  Second border of the paint interval

double QwtScaleMap::pDist | ( |  | ) | const`[inline]`

Returns:
  qwtAbs(p2() - p1())

double QwtScaleMap::s1 | ( |  | ) | const`[inline]`

Returns:
  First border of the scale interval

double QwtScaleMap::s2 | ( |  | ) | const`[inline]`

Returns:
  Second border of the scale interval

double QwtScaleMap::sDist | ( |  | ) | const`[inline]`

Returns:
  qwtAbs(s2() - s1())

void QwtScaleMap::setPaintInterval | ( | double | p1,
|  | double | p2
| ) |  |

Specify the borders of the paint device interval.

Parameters:

  p1 | first border
  p2 | second border

void QwtScaleMap::setScaleInterval | ( | double | s1,
|  | double | s2
| ) |  |

Specify the borders of the scale interval.

Parameters:

  s1 | first border
  s2 | second border

Warning:
  logarithmic scales might be aligned to [LogMin, LogMax]

void QwtScaleMap::setTransformation | ( | QwtScaleTransformation * | transformation | ) |

Initialize the map with a transformation

QPointF QwtScaleMap::transform | ( | const QwtScaleMap & | xMap,
|  | const QwtScaleMap & | yMap,
|  | const QPointF & | pos
| ) |  | `[static]`

Transform a point from scale to paint coordinates

Parameters:

  xMap | X map
  yMap | Y map
  pos | Position in scale coordinates

Returns:
  Position in paint coordinates

See also:
  invTransform()

double QwtScaleMap::transform | ( | double | s | ) | const`[inline]`

Transform a point related to the scale interval into an point related to the interval of the paint device

Parameters:

  s | Value relative to the coordinates of the scale

QRectF QwtScaleMap::transform | ( | const QwtScaleMap & | xMap,
|  | const QwtScaleMap & | yMap,
|  | const QRectF & | rect
| ) |  | `[static]`

Transform a rectangle from scale to paint coordinates

Parameters:

  xMap | X map
  yMap | Y map
  rect | Rectangle in scale coordinates

Returns:
  Rectangle in paint coordinates

See also:
  invTransform()

const QwtScaleTransformation * QwtScaleMap::transformation | ( |  | ) | const

Get the transformation.

## Member Data Documentation

QT_STATIC_CONST_IMPL double QwtScaleMap::LogMax = 1.0e150

Largest allowed value for logarithmic scales: 1.0e150.

QT_STATIC_CONST_IMPL double QwtScaleMap::LogMin = 1.0e-150

Smallest allowed value for logarithmic scales: 1.0e-150.