QwtPlotRescaler(3)

📦

version 6.3.0 · 6 versions

🌸 QwtPlotRescaler(3) — Library Functions Manual 🌸

okay bestie, sit down, grab a strawberry drink 🍓, because we're diving into QwtPlotRescaler — and no, it's not a plugin for making your plots look thinner. it's the icon that handles fixed aspect ratios for plot scales. periodt. 💅

✨ NAME ✨

QwtPlotRescaler — literally takes care of fixed aspect ratios for plot scales. that's the whole job. that's the gig. she's focused. 👑

✨ SYNOPSIS ✨

#include <qwt_plot_rescaler.h>

Inherits QObject. yes, she's a proper Qt citizen, she's got signals-and-slots energy, she belongs. 🫶

🎀 Public Types 🎀

enum RescalePolicy { Fixed, Expanding, Fitting } — the three vibes of how she rescales stuff.
enum ExpandingDirection { ExpandUp, ExpandDown, ExpandBoth } — which end of the scale gets to grow when she's in her Expanding era.

🦋 Public Member Functions 🦋

QwtPlotRescaler (QWidget *canvas, QwtAxisId referenceAxis=QwtAxis::XBottom, RescalePolicy=Expanding) — the constructor, aka her grand entrance ✨
virtual ~QwtPlotRescaler () — Destructor. she's leaving, say bye 👋
void setEnabled (bool) — En/disable the rescaler. she can be turned on and off, like your read receipts.
bool isEnabled () const — is she enabled tho? 🤔
void setRescalePolicy (RescalePolicy) — pick her rescale strategy.
RescalePolicy rescalePolicy () const — tells you which strategy she's currently serving.
void setExpandingDirection (ExpandingDirection) — set the direction for the default/every-axis case.
void setExpandingDirection (QwtAxisId, ExpandingDirection) — same but for one specific axis, iykyk.
ExpandingDirection expandingDirection (QwtAxisId) const — ask about one axis's expanding direction.
void setReferenceAxis (QwtAxisId) — crowns a new reference axis 👑
QwtAxisId referenceAxis () const — who's the reference axis rn?
void setAspectRatio (double ratio) — set the ratio for the whole plot.
void setAspectRatio (QwtAxisId, double ratio) — set the ratio for one axis specifically.
double aspectRatio (QwtAxisId) const — get the ratio for an axis.
void setIntervalHint (QwtAxisId, const QwtInterval &) — drop an interval hint for an axis.
QwtInterval intervalHint (QwtAxisId) const — read back the interval hint.
QWidget * canvas () — the canvas pointer, non-const edition.
const QWidget * canvas () const — the canvas pointer, const edition, no touchy.
QwtPlot * plot () — the plot pointer.
const QwtPlot * plot () const — const plot pointer, look don't touch.
virtual bool eventFilter (QObject *, QEvent *) override — Event filter for the plot canvas. she's watching. 👀
void rescale () const — Adjust the plot axes scales. the main character moment.

💜 Protected Member Functions 💜

virtual void canvasResizeEvent (QResizeEvent *) — handles the canvas resize.
virtual void rescale (const QSize &oldSize, const QSize &newSize) const — the internal rescale doing the math between two sizes.
virtual QwtInterval expandScale (QwtAxisId, const QSize &oldSize, const QSize &newSize) const — works out the expanded scale for an axis.
virtual QwtInterval syncScale (QwtAxisId, const QwtInterval &reference, const QSize &size) const — syncs a scale to a reference interval at a given size.
virtual void updateScales (QwtInterval intervals[QwtAxis::AxisPositions]) const — pushes the new intervals into all the axes.
Qt::Orientation orientation (QwtAxisId) const — horizontal or vertical? the axis decides.
QwtInterval interval (QwtAxisId) const — grab the current interval for an axis.
QwtInterval expandInterval (const QwtInterval &, double width, ExpandingDirection) const — expand a given interval by a width, in a chosen direction.

✨ Detailed Description ✨

QwtPlotRescaler takes care of fixed aspect ratios for plot scales. fr fr, that's her whole personality and she's thriving. 🌈

QwtPlotRescaler auto adjusts the axes of a QwtPlot according to fixed aspect ratios. so you don't have to sit there manually nudging axis limits every time the window resizes — she handles it, you vibe. 💖

Definition at line 29 of file qwt_plot_rescaler.h. (yes she has receipts. 😌)

🧚 Member Enumeration Documentation 🧚

💫 enum QwtPlotRescaler::ExpandingDirection 💫

when rescalePolicy() is set to Expanding, its direction depends on ExpandingDirection. so this enum is literally the steering wheel for her expanding era. 🔥

Enumerators

ExpandUp — The upper limit of the scale is adjusted. she grows upward, ambitious queen. ⭐
ExpandDown — The lower limit of the scale is adjusted. going down, but make it deliberate. 🦋
ExpandBoth — Both limits of the scale are adjusted. why choose, bestie. 💅

Definition at line 70 of file qwt_plot_rescaler.h.

💫 enum QwtPlotRescaler::RescalePolicy 💫

The rescale policy defines how to rescale the reference axis and their depending axes. this is the big-picture strategy, the blueprint, the vision board. ✨

See also: ExpandingDirection, setIntervalHint()

Enumerators

Fixed — The interval of the reference axis remains unchanged, when the geometry of the canvas changes. All other axes will be adjusted according to their aspect ratio. so the reference axis stays exactly as she is, no cap, and everyone else adapts to her. main character reference axis energy honestly. 👑
Expanding — The interval of the reference axis will be shrunk/expanded, when the geometry of the canvas changes. All other axes will be adjusted according to their aspect ratio. and — important detail, don't skip it — the interval, that is represented by one pixel is fixed. 📏
Fitting — The intervals of the axes are calculated, so that all axes include their interval hint. this is where those interval hints from setIntervalHint() finally get their moment. 🌸

Definition at line 40 of file qwt_plot_rescaler.h.

🍓 Constructor & Destructor Documentation 🍓

🌟 `QwtPlotRescaler::QwtPlotRescaler (QWidget * canvas, QwtAxisId referenceAxis = QwtAxis::XBottom, RescalePolicy policy = Expanding) [explicit]` 🌟

Constructor. her debut. the origin story. 🎀

Parameters:
- canvas — Canvas
- referenceAxis — Reference axis, see RescalePolicy
- policy — Rescale policy

See also: setRescalePolicy(), setReferenceAxis()

Definition at line 71 of file qwt_plot_rescaler.cpp.

🌟 `QwtPlotRescaler::~QwtPlotRescaler () [virtual]` 🌟

Destructor. she's logging off, closing her tabs, turning off her phone. goodbye icon. 😭💜

Definition at line 83 of file qwt_plot_rescaler.cpp.

to be continued, bestie — there's more where this came from 🦋

💅 MEMBER FUNCTION DOCUMENTATION 💅

okay bestie, buckle up — this is the full member-function lineup, and every single one is getting its moment. no skipping, no “we’ll come back to it,” periodt. 💖✨

`double QwtPlotRescaler::aspectRatio (QwtAxisId axisId) const`

Returns: the aspect ratio between an axis and the reference axis. cute, concise, iconic. 🌸

axisId — Axis

See also: setAspectRatio()

Definition: at line 243 of file qwt_plot_rescaler.cpp.

`QWidget * QwtPlotRescaler::canvas ()`

Returns: plot canvas 🎨

Definition: at line 282 of file qwt_plot_rescaler.cpp.

`const QWidget * QwtPlotRescaler::canvas () const`

Returns: plot canvas 🎨

Definition: at line 288 of file qwt_plot_rescaler.cpp.

`void QwtPlotRescaler::canvasResizeEvent (QResizeEvent * event)` — [protected], [virtual]

Event handler for resize events of the plot canvas. very “notify me when the canvas changes” energy. 🦋

event — Resize event

See also: rescale()

Definition: at line 343 of file qwt_plot_rescaler.cpp.

`bool QwtPlotRescaler::eventFilter (QObject * object, QEvent * event)` — [override], [virtual]

Event filter for the plot canvas. that’s it, that’s the whole mood. 💅

Definition: at line 314 of file qwt_plot_rescaler.cpp.

`QwtPlotRescaler::ExpandingDirection QwtPlotRescaler::expandingDirection (QwtAxisId axisId) const`

Returns: the direction in which an axis should be expanded. directional queen 👑

axisId — Axis

See also: setExpandingDirection()

Definition: at line 197 of file qwt_plot_rescaler.cpp.

`QwtInterval QwtPlotRescaler::expandInterval (const QwtInterval & interval, double width, ExpandingDirection direction) const` — [protected]

Expand the interval. literally stretching the vibe. 🌈

interval — Interval to be expanded
width — Distance to be added to the interval
direction — Direction of the expand operation

Returns: expanded interval

Definition: at line 526 of file qwt_plot_rescaler.cpp.

`QwtInterval QwtPlotRescaler::expandScale (QwtAxisId axisId, const QSize & oldSize, const QSize & newSize) const` — [protected], [virtual]

Calculate the new scale interval of a plot axis. math but make it fashion. 🧮✨

axisId — Axis
oldSize — Previous size of the canvas
newSize — New size of the canvas

Returns: calculated new interval for the axis

Definition: at line 405 of file qwt_plot_rescaler.cpp.

`QwtInterval QwtPlotRescaler::interval (QwtAxisId axisId) const` — [protected]

axisId — Axis

Returns: normalized interval of an axis

Definition: at line 509 of file qwt_plot_rescaler.cpp.

`QwtInterval QwtPlotRescaler::intervalHint (QwtAxisId axisId) const`

axisId — Axis

Returns: interval hint

See also: setIntervalHint(), RescalePolicy

Definition: at line 273 of file qwt_plot_rescaler.cpp.

`bool QwtPlotRescaler::isEnabled () const`

Returns: true when enabled, false otherwise. binary baddie behavior. 💀

See also: setEnabled, eventFilter()

Definition: at line 118 of file qwt_plot_rescaler.cpp.

`Qt::Orientation QwtPlotRescaler::orientation (QwtAxisId axisId) const` — [protected]

Returns: orientation of an axis 🧭

axisId — Axis

Definition: at line 500 of file qwt_plot_rescaler.cpp.

`QwtPlot * QwtPlotRescaler::plot ()`

Returns: plot widget 📊

Definition: at line 294 of file qwt_plot_rescaler.cpp.

`const QwtPlot * QwtPlotRescaler::plot () const`

Returns: plot widget 📊

Definition: at line 304 of file qwt_plot_rescaler.cpp.

`QwtAxisId QwtPlotRescaler::referenceAxis () const`

Returns: reference axis (see RescalePolicy). the main-character axis, basically. 👑

See also: setReferenceAxis()

Definition: at line 158 of file qwt_plot_rescaler.cpp.

`void QwtPlotRescaler::rescale () const`

Adjust the plot axes scales. go off, scales. 🔥

Definition: at line 355 of file qwt_plot_rescaler.cpp.

`void QwtPlotRescaler::rescale (const QSize & oldSize, const QSize & newSize) const` — [protected], [virtual]

Adjust the plot axes scales. same energy, now with size lore. 📐

oldSize — Previous size of the canvas
newSize — New size of the canvas

Definition: at line 367 of file qwt_plot_rescaler.cpp.

`QwtPlotRescaler::RescalePolicy QwtPlotRescaler::rescalePolicy () const`

Returns: rescale policy 📜

See also: setRescalePolicy()

Definition: at line 138 of file qwt_plot_rescaler.cpp.

`void QwtPlotRescaler::setAspectRatio (double ratio)`

Set the aspect ratio between the scale of the reference axis and the other scales. The default ratio is 1.0. slay that default. 💅

ratio — Aspect ratio

See also: aspectRatio()

Definition: at line 212 of file qwt_plot_rescaler.cpp.

`void QwtPlotRescaler::setAspectRatio (QwtAxisId axisId, double ratio)`

Set the aspect ratio between the scale of the reference axis and another scale. The default ratio is 1.0. yes, again, and it ate. ✨

axisId — Axis
ratio — Aspect ratio

See also: aspectRatio()

Definition: at line 226 of file qwt_plot_rescaler.cpp.

`void QwtPlotRescaler::setEnabled (bool on)`

En/disable the rescaler. When enabled is true, an event filter is installed for the canvas; otherwise the event filter is removed. toggle toggle, bestie. 🔘

on — true or false

See also: isEnabled(), eventFilter()

Definition: at line 97 of file qwt_plot_rescaler.cpp.

`void QwtPlotRescaler::setExpandingDirection (ExpandingDirection direction)`

Set the direction in which all axis should be expanded. all of them. collectively. 💫

direction — Direction

See also: expandingDirection()

Definition: at line 169 of file qwt_plot_rescaler.cpp.

`void QwtPlotRescaler::setExpandingDirection (QwtAxisId axisId, ExpandingDirection direction)`

Set the direction in which an axis should be expanded. one axis, very personal. 🎀

axisId — Axis
direction — Direction

See also: expandingDirection()

Definition: at line 183 of file qwt_plot_rescaler.cpp.

`void QwtPlotRescaler::setIntervalHint (QwtAxisId axisId, const QwtInterval & interval)`

Set an interval hint for an axis. In Fitting mode, the hint is used as minimal interval that always needs to be displayed. noted and respected. 📝

axisId — Axis
interval — Axis

See also: intervalHint(), RescalePolicy

Definition: at line 261 of file qwt_plot_rescaler.cpp.

`void QwtPlotRescaler::setReferenceAxis (QwtAxisId axisId)`

Set the reference axis (see RescalePolicy). crown the reference axis, honestly. 👑

axisId — Axis

See also: referenceAxis()

Definition: at line 149 of file qwt_plot_rescaler.cpp.

`void QwtPlotRescaler::setRescalePolicy (RescalePolicy policy)`

Change the rescale policy. new policy, who dis? 🦋

policy — Rescale policy

See also: rescalePolicy()

Definition: at line 129 of file qwt_plot_rescaler.cpp.

`QwtInterval QwtPlotRescaler::syncScale (QwtAxisId axisId, const QwtInterval & reference, const QSize & size) const` — [protected], [virtual]

Synchronize an axis scale according to the scale of the reference axis. teamwork makes the dream work. 🫶

axisId — Axis
reference — Interval of the reference axis
size — Size of the canvas

Returns: new interval for axis

Definition: at line 469 of file qwt_plot_rescaler.cpp.

`void QwtPlotRescaler::updateScales (QwtInterval intervals[QwtAxis::AxisPositions]) const` — [protected], [virtual]

Update the axes scales. all together now. 📈

intervals — Scale intervals

Definition: at line 588 of file qwt_plot_rescaler.cpp.

✨ AUTHOR ✨

Generated automatically by Doxygen for Qwt User's Guide from the source code. iconic autogenerated behavior, no notes. 🎀

💖 footer vibe check, bestie: this page is auto-generated by Doxygen for Qwt User's Guide from the source code, and the footer tag is QwtPlotRescaler(3) — no actual date/version line on this one, so I’m not inventing one. byeee 💅✨

📦 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

QwtPlotRescaler(3)