QwtAbstractScale(3)

📦

version 6.3.0 · 6 versions

okay so bestie, welcome to QwtAbstractScale(3) from the Library Functions Manual — this is the abstract base class for widgets that have a scale, and it is lowkey foundational. slay 💅

🎀 NAME 🎀

QwtAbstractScale - an abstract base class for widgets having a scale. periodt, that's the whole name vibe: scale-having widget energy. ✨

✨ SYNOPSIS ✨

#include <qwt_abstract_scale.h>

Inherits QWidget.

Inherited by QwtAbstractSlider, and QwtThermo.

So it's a QWidget, and QwtAbstractSlider and QwtThermo inherit from it. it's giving family tree realness. 🌸

💖 Public Member Functions 💖

QwtAbstractScale (QWidget *parent=NULL) — the constructor, with parent as a QWidget *.
virtual ~QwtAbstractScale () — destructor. bye bestie.
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 — the scale division getter.
void setLowerBound (double value) — lower-bound setter.
double lowerBound () const — lower-bound getter.
void setUpperBound (double value) — upper-bound setter.
double upperBound () const — upper-bound getter.
void setScaleStepSize (double stepSize) — set the step size used for calculating a scale division.
double scaleStepSize () const — step-size getter.
void setScaleMaxMajor (int ticks) — set the maximum number of major tick intervals.
int scaleMaxMinor () const — max minor tick intervals getter. yes, this one shows up before its setter in the original — iconic order, no notes.
void setScaleMaxMinor (int ticks) — set the maximum number of minor tick intervals.
int scaleMaxMajor () const — max major tick intervals getter.
void setScaleEngine (QwtScaleEngine *) — set a scale engine.
const QwtScaleEngine * scaleEngine () const — const scale-engine getter.
QwtScaleEngine * scaleEngine () — scale-engine getter.
int transform (double) const — transform call: takes a double, returns an int.
double invTransform (int) const — inverse transform call: takes an int, returns a double.
bool isInverted () const — inverted check, returns a bool.
double minimum () const — minimum getter.
double maximum () const — maximum getter.
const QwtScaleMap & scaleMap () const — scale-map getter.

🦋 Protected Member Functions 🦋

virtual void changeEvent (QEvent *) override — change-event override.
void rescale (double lowerBound, double upperBound, double stepSize) — rescale with lowerBound, upperBound, and stepSize.
void setAbstractScaleDraw (QwtAbstractScaleDraw *) — set a scale draw.
const QwtAbstractScaleDraw * abstractScaleDraw () const — const abstract-scale-draw getter.
QwtAbstractScaleDraw * abstractScaleDraw () — abstract-scale-draw getter.
void updateScaleDraw () — update the scale draw.
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. obsessed with this separation of concerns. ✨

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 ... ). linear? logarithmic? the scale engine said choose your fighter.

Definition at line 36 of file qwt_abstract_scale.h.

🧚 Constructor & Destructor Documentation 🧚

`QwtAbstractScale::QwtAbstractScale (QWidget * parent = NULL) [explicit]`

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.

bestie, yes, the original literally says scaleMaxMajor twice there — I am not fixing it, I am respecting the lore. iykyk 💅

Definition at line 57 of file qwt_abstract_scale.cpp.

`QwtAbstractScale::~QwtAbstractScale () [virtual]`

Destructor. cleanup era. 💖

Definition at line 65 of file qwt_abstract_scale.cpp.

💅 Member Function Documentation 💅

okay bestie, this is the member-function half of the page — every method, every return, every see-also, all of it. no skips, no cap. ✨

🎀 `abstractScaleDraw()` — non-const glow-up

QwtAbstractScaleDraw * QwtAbstractScale::abstractScaleDraw () [protected]

Returns: Scale draw 💖
See also: setAbstractScaleDraw()
Definition: Definition at line 293 of file qwt_abstract_scale.cpp.

🦋 `abstractScaleDraw()` — const queen

const QwtAbstractScaleDraw * QwtAbstractScale::abstractScaleDraw () const
       [protected]

Returns: Scale draw ✨
See also: setAbstractScaleDraw()
Definition: Definition at line 302 of file qwt_abstract_scale.cpp.

🌸 `changeEvent()` — the event-handler moment

void QwtAbstractScale::changeEvent (QEvent * event) [override],
       [protected],  [virtual]

Change Event handler, literally.

Parameters: event — Change event
Invalidates internal caches if necessary 🧹
Reimplemented in QwtDial, QwtKnob, QwtSlider, and QwtThermo.
Definition: Definition at line 453 of file qwt_abstract_scale.cpp.

🧚 `invTransform()` — widget coord → scale value

double QwtAbstractScale::invTransform (int value) const

Translate a widget coordinate into a scale value. it's giving translator bestie 💅

Parameters: value — Widget coordinate
Returns: Corresponding scale coordinate for value
See also: scaleMap(), transform()
Definition: Definition at line 381 of file qwt_abstract_scale.cpp.

🦋 `isInverted()` — is the scale going backwards?

bool QwtAbstractScale::isInverted () const

Returns: True, when the scale is increasing in opposite direction to the widget coordinates 👀
Definition: Definition at line 390 of file qwt_abstract_scale.cpp.

🍓 `lowerBound()` — bottom of the scale

double QwtAbstractScale::lowerBound () const

Returns: Lower bound of the scale
See also: setLowerBound(), setScale(), upperBound()
Definition: Definition at line 88 of file qwt_abstract_scale.cpp.

👑 `maximum()` — the bigger boundary

double QwtAbstractScale::maximum () const

Returns: The boundary with the larger value
See also: minimum(), lowerBound(), upperBound()
Definition: Definition at line 409 of file qwt_abstract_scale.cpp.

🎀 `minimum()` — the smaller boundary

double QwtAbstractScale::minimum () const

Returns: The boundary with the smaller value
See also: maximum(), lowerBound(), upperBound()
Definition: Definition at line 399 of file qwt_abstract_scale.cpp.

🔥 `rescale()` — recalculate + update

void QwtAbstractScale::rescale (double lowerBound, double upperBound, double
       stepSize) [protected]

Recalculate the scale division and update the scale. main character energy, fr fr.

Parameters:
- lowerBound — Lower limit of the scale interval
- upperBound — Upper limit of the scale interval
- stepSize — Major step size
See also: scaleChange()
Definition: Definition at line 429 of file qwt_abstract_scale.cpp.

💫 `scaleChange()` — notify changed scale

void QwtAbstractScale::scaleChange () [protected],  [virtual]

Notify changed scale. that's the whole vibe.

Reimplemented in QwtAbstractSlider, QwtDial, QwtSlider, and QwtThermo.
Definition: Definition at line 416 of file qwt_abstract_scale.cpp.

🌈 `scaleDiv()` — boundaries + tick positions

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(). iykyk 🫶
Definition: Definition at line 349 of file qwt_abstract_scale.cpp.

🧚 `scaleEngine()` — non-const version

QwtScaleEngine * QwtAbstractScale::scaleEngine ()

Returns: Scale engine
See also: setScaleEngine()
Definition: Definition at line 338 of file qwt_abstract_scale.cpp.

🦋 `scaleEngine()` — const version

const QwtScaleEngine * QwtAbstractScale::scaleEngine () const

Returns: Scale engine
See also: setScaleEngine()
Definition: Definition at line 329 of file qwt_abstract_scale.cpp.

🗺️ `scaleMap()` — the coordinate map

const QwtScaleMap & QwtAbstractScale::scaleMap () const

Returns: Map to translate between scale and widget coordinates
Definition: Definition at line 357 of file qwt_abstract_scale.cpp.

💅 `scaleMaxMajor()` — max major intervals

int QwtAbstractScale::scaleMaxMajor () const

Returns: Maximal number of major tick intervals
See also: setScaleMaxMajor(), scaleMaxMinor()
Definition: Definition at line 202 of file qwt_abstract_scale.cpp.

🌸 `scaleMaxMinor()` — max minor intervals

int QwtAbstractScale::scaleMaxMinor () const

Returns: Maximal number of minor tick intervals
See also: setScaleMaxMinor(), scaleMaxMajor()
Definition: Definition at line 232 of file qwt_abstract_scale.cpp.

⭐ `scaleStepSize()` — step-size hint

double QwtAbstractScale::scaleStepSize () const

Returns: Hint for the step size of the scale
See also: setScaleStepSize(), QwtScaleEngine::divideScale()
Definition: Definition at line 264 of file qwt_abstract_scale.cpp.

🎀 `setAbstractScaleDraw()` — adopt a scale draw

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(). no leaks, bestie 💖

See also: abstractScaleDraw()
Definition: Definition at line 277 of file qwt_abstract_scale.cpp.

🍓 `setLowerBound()` — set the lower bound

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 👀
Definition: Definition at line 79 of file qwt_abstract_scale.cpp.

🧚 `setScale()` — scale by interval

void QwtAbstractScale::setScale (const QwtInterval & interval)

Specify a scale. Define a scale by an interval.

The ticks are calculated using scaleMaxMinor(), scaleMaxMajor() and scaleStepSize(). math girlie behavior, honestly.

Parameters: interval — Interval
Definition: Definition at line 145 of file qwt_abstract_scale.cpp.

🦋 `setScale()` — scale by scale division

void QwtAbstractScale::setScale (const QwtScaleDiv & scaleDiv)

Specify a scale. scaleMaxMinor(), scaleMaxMajor() and scaleStepSize() and have no effect. yes, that's the note — fr fr.

Parameters: scaleDiv — Scale division
See also: setAutoScale()
Definition: Definition at line 158 of file qwt_abstract_scale.cpp.

🌈 `setScale()` — scale by two bounds

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 👑
Definition: Definition at line 130 of file qwt_abstract_scale.cpp.

🔥 `setScaleEngine()` — swap in a scale engine

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. that's a lot of responsibility, tbh.

scaleEngine has to be created with new and will be deleted in the destructor or the next call of setScaleEngine.

Definition: Definition at line 316 of file qwt_abstract_scale.cpp.

💫 `setScaleMaxMajor()` — cap those major ticks

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. periodt.

Parameters: ticks — Maximal number of major ticks.
See also: scaleMaxMajor(), setScaleMaxMinor(), setScaleStepSize(), QwtScaleEngine::divideInterval()
Definition: Definition at line 189 of file qwt_abstract_scale.cpp.

🌸 `setScaleMaxMinor()` — cap those minor ticks

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. slay.

Parameters: ticks — Maximal number of minor ticks.
See also: scaleMaxMajor(), setScaleMaxMinor(), setScaleStepSize(), QwtScaleEngine::divideInterval()
Definition: Definition at line 219 of file qwt_abstract_scale.cpp.

⭐ `setScaleStepSize()` — hint the step size

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().
Definition: Definition at line 251 of file qwt_abstract_scale.cpp.

🎀 `setUpperBound()` — set the upper bound

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 💅
Definition: Definition at line 102 of file qwt_abstract_scale.cpp.

🗺️ `transform()` — scale value → widget coord

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()
Definition: Definition at line 369 of file qwt_abstract_scale.cpp.

🧹 `updateScaleDraw()` — recalculate everything

void QwtAbstractScale::updateScaleDraw () [protected]

Recalculate ticks and scale boundaries. get that refresh, bestie ✨

Definition: Definition at line 466 of file qwt_abstract_scale.cpp.

👑 `upperBound()` — top of the scale

double QwtAbstractScale::upperBound () const

Returns: Upper bound of the scale
See also: setUpperBound(), setScale(), lowerBound()
Definition: Definition at line 111 of file qwt_abstract_scale.cpp.

👑 Author 👑

Generated automatically by Doxygen for Qwt User's Guide from the source code. yes, the robots wrote this bit, and it ate. 💖

and that's the footer vibe, bestie — source/version says Qwt User's Guide, page QwtAbstractScale(3), no extra drama, just a cute little sign-off ✨🫶

📦 where this page comes from

alpine 3.24: qwt-doc 6.3.0-r0 · custom
💖 girlified by deepseek-ai/DeepSeek-V4.1-Flash-1017 on 2026-11-04: a language model's rewrite of the original, under its terms

QwtAbstractScale(3)

🎀 NAME 🎀

✨ SYNOPSIS ✨

💖 Public Member Functions 💖

🦋 Protected Member Functions 🦋

💖 Detailed Description 💖

🧚 Constructor & Destructor Documentation 🧚

QwtAbstractScale::QwtAbstractScale (QWidget * parent = NULL) [explicit]

QwtAbstractScale::~QwtAbstractScale () [virtual]

💅 Member Function Documentation 💅

🎀 abstractScaleDraw() — non-const glow-up

🦋 abstractScaleDraw() — const queen

🌸 changeEvent() — the event-handler moment

🧚 invTransform() — widget coord → scale value

🦋 isInverted() — is the scale going backwards?

🍓 lowerBound() — bottom of the scale

👑 maximum() — the bigger boundary

🎀 minimum() — the smaller boundary

🔥 rescale() — recalculate + update

💫 scaleChange() — notify changed scale

🌈 scaleDiv() — boundaries + tick positions

🧚 scaleEngine() — non-const version

🦋 scaleEngine() — const version

🗺️ scaleMap() — the coordinate map

💅 scaleMaxMajor() — max major intervals

🌸 scaleMaxMinor() — max minor intervals

⭐ scaleStepSize() — step-size hint

🎀 setAbstractScaleDraw() — adopt a scale draw

🍓 setLowerBound() — set the lower bound

🧚 setScale() — scale by interval

🦋 setScale() — scale by scale division

🌈 setScale() — scale by two bounds

🔥 setScaleEngine() — swap in a scale engine

💫 setScaleMaxMajor() — cap those major ticks

🌸 setScaleMaxMinor() — cap those minor ticks

⭐ setScaleStepSize() — hint the step size

🎀 setUpperBound() — set the upper bound

🗺️ transform() — scale value → widget coord

🧹 updateScaleDraw() — recalculate everything

👑 upperBound() — top of the scale