---
name: "QwtScaleMap"
section: "3"
platform: "linux"
package: "libqwt-doc"
version: "6.1.4-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/QwtScaleMap"
---

# QwtScaleMap(3)

A scale map.

## NAME

QwtScaleMap - A scale map.

## SYNOPSIS

`#include <qwt_scale_map.h>`

### Public Member Functions

**QwtScaleMap** ()\
 Constructor.  **QwtScaleMap** (const **QwtScaleMap** &)\
 Copy constructor.  **~QwtScaleMap** ()\
 **QwtScaleMap** & **operator=** (const **QwtScaleMap** &)\
 Assignment operator.  void **setTransformation** (**QwtTransform** \*)\
 const **QwtTransform** \* **transformation** () const\
 Get the transformation.  void **setPaintInterval** (double **p1**, double **p2**)\
 Specify the borders of the paint device interval.  void **setScaleInterval** (double **s1**, double **s2**)\
 Specify the borders of the scale interval.  double **transform** (double s) const\
 double **invTransform** (double p) const\
 double **p1** () const\
 double **p2** () const\
 double **s1** () const\
 double **s2** () const\
 double **pDist** () const\
 double **sDist** () const\
 bool **isInverting** () const\

### Static Public Member Functions

static QRectF **transform** (const **QwtScaleMap** &, const **QwtScaleMap** &, const QRectF &)\
 static QRectF **invTransform** (const **QwtScaleMap** &, const **QwtScaleMap** &, const QRectF &)\
 static QPointF **transform** (const **QwtScaleMap** &, const **QwtScaleMap** &, const QPointF &)\
 static QPointF **invTransform** (const **QwtScaleMap** &, const **QwtScaleMap** &, const QPointF &)\

## 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 ()

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

**Returns:**

Transformed value

**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()**

### 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()**

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

**Returns:**

True, when ( **p1()** \< **p2()** ) != ( **s1()** \< **s2()** )

### 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:**

scales might be aligned to transformation depending boundaries

### void QwtScaleMap::setTransformation (QwtTransform \* transform)

Initialize the map with a transformation

### 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

**Returns:**

Transformed value

**See also:**

**invTransform()**

### 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()**

### 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()**

## Author

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