--- name: "QwtAbstractScale" section: "3" platform: "linux" package: "libqwt-doc" version: "6.1.4-2" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/QwtAbstractScale" --- # QwtAbstractScale(3) An abstract base class for widgets having a scale. ## NAME QwtAbstractScale - An abstract base class for widgets having a scale. ## SYNOPSIS `#include ` Inherits QWidget. Inherited by **QwtAbstractSlider**, and **QwtThermo**. ### Public Member Functions **QwtAbstractScale** (QWidget \*parent=NULL)\ virtual **~QwtAbstractScale** ()\ Destructor. void **setScale** (double **lowerBound**, double **upperBound**)\ Specify a scale. void **setScale** (const **QwtInterval** &)\ Specify a scale. void **setScale** (const **QwtScaleDiv** &)\ Specify a scale. const **QwtScaleDiv** & **scaleDiv** () const\ void **setLowerBound** (double value)\ double **lowerBound** () const\ void **setUpperBound** (double value)\ double **upperBound** () const\ void **setScaleStepSize** (double stepSize)\ Set the step size used for calculating a scale division. double **scaleStepSize** () const\ void **setScaleMaxMajor** (int ticks)\ Set the maximum number of major tick intervals. int **scaleMaxMinor** () const\ void **setScaleMaxMinor** (int ticks)\ Set the maximum number of minor tick intervals. int **scaleMaxMajor** () const\ void **setScaleEngine** (**QwtScaleEngine** \*)\ Set a scale engine. const **QwtScaleEngine** \* **scaleEngine** () const\ **QwtScaleEngine** \* **scaleEngine** ()\ int **transform** (double) const\ double **invTransform** (int) const\ bool **isInverted** () const\ double **minimum** () const\ double **maximum** () const\ const **QwtScaleMap** & **scaleMap** () const\ ### Protected Member Functions void **rescale** (double **lowerBound**, double **upperBound**, double stepSize)\ void **setAbstractScaleDraw** (**QwtAbstractScaleDraw** \*)\ Set a scale draw. const **QwtAbstractScaleDraw** \* **abstractScaleDraw** () const\ **QwtAbstractScaleDraw** \* **abstractScaleDraw** ()\ virtual void **scaleChange** ()\ Notify changed scale. ## Detailed Description An abstract base class for widgets having a scale. The scale of an **QwtAbstractScale** is determined by a **QwtScaleDiv** definition, that contains the boundaries and the ticks of the scale. The scale is painted using a **QwtScaleDraw** object. The scale division might be assigned explicitly - but usually it is calculated from the boundaries using a **QwtScaleEngine**. The scale engine also decides the type of transformation of the scale ( linear, logarithmic ... ). ## Constructor & Destructor Documentation ### QwtAbstractScale::QwtAbstractScale (QWidget \* parent = `NULL`) Constructor **Parameters:** *parent* Parent widget Creates a default **QwtScaleDraw** and a **QwtLinearScaleEngine**. The initial scale boundaries are set to \[ 0.0, 100.0 \] The **scaleStepSize()** is initialized to 0.0, **scaleMaxMajor()** to 5 and scaleMaxMajor to 3. ## Member Function Documentation ### const QwtAbstractScaleDraw \* QwtAbstractScale::abstractScaleDraw () const` [protected]` **Returns:** Scale draw **See also:** **setAbstractScaleDraw()** ### QwtAbstractScaleDraw \* QwtAbstractScale::abstractScaleDraw ()` [protected]` **Returns:** Scale draw **See also:** **setAbstractScaleDraw()** ### double QwtAbstractScale::invTransform (int value) const Translate a widget coordinate into a scale value **Parameters:** *value* Widget coordinate **Returns:** Corresponding scale coordinate for value **See also:** **scaleMap()**, **transform()** ### bool QwtAbstractScale::isInverted () const **Returns:** True, when the scale is increasing in opposite direction to the widget coordinates ### double QwtAbstractScale::lowerBound () const **Returns:** Lower bound of the scale **See also:** **setLowerBound()**, **setScale()**, **upperBound()** ### double QwtAbstractScale::maximum () const **Returns:** The boundary with the larger value **See also:** **minimum()**, **lowerBound()**, **upperBound()** ### double QwtAbstractScale::minimum () const **Returns:** The boundary with the smaller value **See also:** **maximum()**, **lowerBound()**, **upperBound()** ### void QwtAbstractScale::rescale (double lowerBound, double upperBound, double stepSize)` [protected]` Recalculate the scale division and update the scale. **Parameters:** *lowerBound* Lower limit of the scale interval \ *upperBound* Upper limit of the scale interval \ *stepSize* Major step size **See also:** **scaleChange()** ### const QwtScaleDiv & QwtAbstractScale::scaleDiv () const **Returns:** Scale boundaries and positions of the ticks The scale division might have been assigned explicitly or calculated implicitly by **rescale()**. ### const QwtScaleEngine \* QwtAbstractScale::scaleEngine () const **Returns:** Scale engine **See also:** **setScaleEngine()** ### QwtScaleEngine \* QwtAbstractScale::scaleEngine () **Returns:** Scale engine **See also:** **setScaleEngine()** ### const QwtScaleMap & QwtAbstractScale::scaleMap () const **Returns:** Map to translate between scale and widget coordinates ### int QwtAbstractScale::scaleMaxMajor () const **Returns:** Maximal number of major tick intervals **See also:** **setScaleMaxMajor()**, **scaleMaxMinor()** ### int QwtAbstractScale::scaleMaxMinor () const **Returns:** Maximal number of minor tick intervals **See also:** **setScaleMaxMinor()**, **scaleMaxMajor()** ### double QwtAbstractScale::scaleStepSize () const **Returns:** Hint for the step size of the scale **See also:** **setScaleStepSize()**, **QwtScaleEngine::divideScale()** ### void QwtAbstractScale::setAbstractScaleDraw (QwtAbstractScaleDraw \* scaleDraw)` [protected]` Set a scale draw. scaleDraw has to be created with new and will be deleted in the destructor or the next call of **setAbstractScaleDraw()**. **See also:** **abstractScaleDraw()** ### void QwtAbstractScale::setLowerBound (double value) Set the lower bound of the scale **Parameters:** *value* Lower bound **See also:** **lowerBound()**, **setScale()**, **setUpperBound()** **Note:** For inverted scales the lower bound is greater than the upper bound ### void QwtAbstractScale::setScale (double lowerBound, double upperBound) Specify a scale. Define a scale by an interval The ticks are calculated using **scaleMaxMinor()**, **scaleMaxMajor()** and **scaleStepSize()**. **Parameters:** *lowerBound* lower limit of the scale interval \ *upperBound* upper limit of the scale interval **Note:** For inverted scales the lower bound is greater than the upper bound ### void QwtAbstractScale::setScale (const QwtInterval & interval) Specify a scale. Define a scale by an interval The ticks are calculated using **scaleMaxMinor()**, **scaleMaxMajor()** and **scaleStepSize()**. **Parameters:** *interval* Interval ### void QwtAbstractScale::setScale (const QwtScaleDiv & scaleDiv) Specify a scale. **scaleMaxMinor()**, **scaleMaxMajor()** and **scaleStepSize()** and have no effect. **Parameters:** *scaleDiv* Scale division **See also:** setAutoScale() ### void QwtAbstractScale::setScaleEngine (QwtScaleEngine \* scaleEngine) Set a scale engine. The scale engine is responsible for calculating the scale division and provides a transformation between scale and widget coordinates. scaleEngine has to be created with new and will be deleted in the destructor or the next call of setScaleEngine. ### void QwtAbstractScale::setScaleMaxMajor (int ticks) Set the maximum number of major tick intervals. The scale's major ticks are calculated automatically such that the number of major intervals does not exceed ticks. The default value is 5. **Parameters:** *ticks* Maximal number of major ticks. **See also:** **scaleMaxMajor()**, **setScaleMaxMinor()**, **setScaleStepSize()**, **QwtScaleEngine::divideInterval()** ### void QwtAbstractScale::setScaleMaxMinor (int ticks) Set the maximum number of minor tick intervals. The scale's minor ticks are calculated automatically such that the number of minor intervals does not exceed ticks. The default value is 3. **Parameters:** *ticks* Maximal number of minor ticks. **See also:** **scaleMaxMajor()**, **setScaleMaxMinor()**, **setScaleStepSize()**, **QwtScaleEngine::divideInterval()** ### void QwtAbstractScale::setScaleStepSize (double stepSize) Set the step size used for calculating a scale division. The step size is hint for calculating the intervals for the major ticks of the scale. A value of 0.0 is interpreted as no hint. **Parameters:** *stepSize* Hint for the step size of the scale **See also:** **scaleStepSize()**, **QwtScaleEngine::divideScale()** **Note:** Position and distance between the major ticks also depends on **scaleMaxMajor()**. ### void QwtAbstractScale::setUpperBound (double value) Set the upper bound of the scale **Parameters:** *value* Upper bound **See also:** **upperBound()**, **setScale()**, **setLowerBound()** **Note:** For inverted scales the lower bound is greater than the upper bound ### int QwtAbstractScale::transform (double value) const Translate a scale value into a widget coordinate **Parameters:** *value* Scale value **Returns:** Corresponding widget coordinate for value **See also:** **scaleMap()**, **invTransform()** ### double QwtAbstractScale::upperBound () const **Returns:** Upper bound of the scale **See also:** **setUpperBound()**, **setScale()**, **lowerBound()** ## Author Generated automatically by Doxygen for Qwt User's Guide from the source code.