QwtPolarPlot - A plotting widget, displaying a polar coordinate system.

NAME

QwtPolarPlot − A plotting widget, displaying a polar coordinate system.

SYNOPSIS

#include <qwt_polar_plot.h>

Inherits QFrame, and QwtPolarItemDict.

Public Types

enum LegendPosition { LeftLegend, RightLegend, BottomLegend, TopLegend, ExternalLegend }

Public Slots

virtual void replot ()
Redraw the plot.
void autoRefresh ()
Replots the plot if QwtPlot::autoReplot() is true.
void setAzimuthOrigin (double)
Change the origin of the azimuth scale.

Signals

void itemAttached (QwtPolarItem *plotItem, bool on)
void legendDataChanged (const QVariant &itemInfo, const QList< QwtLegendData > &data)
void layoutChanged ()

Public Member Functions

QwtPolarPlot (QWidget *parent=NULL)
QwtPolarPlot (const QwtText &title, QWidget *parent=NULL)
virtual ˜QwtPolarPlot ()
Destructor.
void setTitle (const QString &)
void setTitle (const QwtText &)
QwtText title () const
QwtTextLabel * titleLabel ()
const QwtTextLabel * titleLabel () const
void setAutoReplot (bool tf=true)
Set or reset the autoReplot option.
bool autoReplot () const
void setAutoScale (int scaleId)
Enable autoscaling.
bool hasAutoScale (int scaleId) const
void setScaleMaxMinor (int scaleId, int maxMinor)
int scaleMaxMinor (int scaleId) const
int scaleMaxMajor (int scaleId) const
void setScaleMaxMajor (int scaleId, int maxMajor)
QwtScaleEngine * scaleEngine (int scaleId)
const QwtScaleEngine * scaleEngine (int scaleId) const
void setScaleEngine (int scaleId, QwtScaleEngine *)
void setScale (int scaleId, double min, double max, double step=0)
Disable autoscaling and specify a fixed scale for a selected scale.
void setScaleDiv (int scaleId, const QwtScaleDiv &)
Disable autoscaling and specify a fixed scale for a selected scale.
const QwtScaleDiv * scaleDiv (int scaleId) const
Return the scale division of a specified scale.
QwtScaleDiv * scaleDiv (int scaleId)
Return the scale division of a specified scale.
QwtScaleMap scaleMap (int scaleId, double radius) const
QwtScaleMap scaleMap (int scaleId) const
void updateScale (int scaleId)
double azimuthOrigin () const
void zoom (const QwtPointPolar &, double factor)
Translate and in/decrease the zoom factor.
void unzoom ()
QwtPointPolar zoomPos () const
double zoomFactor () const
QwtPolarCanvas * canvas ()
const QwtPolarCanvas * canvas () const
void setPlotBackground (const QBrush &c)
Set the background of the plot area.
const QBrush & plotBackground () const
virtual void drawCanvas (QPainter *, const QRectF &) const
void insertLegend (QwtAbstractLegend *, LegendPosition=RightLegend, double ratio=−1.0)
Insert a legend.
QwtAbstractLegend * legend ()
const QwtAbstractLegend * legend () const
void updateLegend ()
void updateLegend (const QwtPolarItem *)
QwtPolarLayout * plotLayout ()
const QwtPolarLayout * plotLayout () const
QwtInterval visibleInterval () const
QRectF plotRect () const
QRectF plotRect (const QRectF &) const
Calculate the bounding rect of the plot area.
int plotMarginHint () const
virtual QVariant itemToInfo (QwtPolarItem *) const
Build an information, that can be used to identify a plot item on the legend.
virtual QwtPolarItem * infoToItem (const QVariant &) const
Identify the plot item according to an item info object, that has bee generated from itemToInfo().

Public Member Functions inherited from QwtPolarItemDict

QwtPolarItemDict ()
˜QwtPolarItemDict ()
void setAutoDelete (bool)
bool autoDelete () const
const QwtPolarItemList & itemList () const
A QwtPolarItemList of all attached plot items.
void detachItems (int rtti=QwtPolarItem::Rtti_PolarItem, bool autoDelete=true)

Protected Member Functions

virtual bool event (QEvent *) override
Qt event handler.
virtual void resizeEvent (QResizeEvent *) override
Resize and update internal layout.
virtual void updateLayout ()
Rebuild the layout.
virtual void drawItems (QPainter *painter, const QwtScaleMap &radialMap, const QwtScaleMap &azimuthMap, const QPointF &pole, double radius, const QRectF &canvasRect) const

Protected Member Functions inherited from QwtPolarItemDict

void insertItem (QwtPolarItem *)
void removeItem (QwtPolarItem *)

Detailed Description

A plotting widget, displaying a polar coordinate system.

An unlimited number of plot items can be displayed on its canvas. Plot items might be curves (QwtPolarCurve), markers (QwtPolarMarker), the grid (QwtPolarGrid), or anything else derived from QwtPolarItem.

The coordinate system is defined by a radial and a azimuth scale. The scales at the axes can be explicitly set (QwtScaleDiv), or are calculated from the plot items, using algorithms (QwtScaleEngine) which can be configured separately for each axis. Autoscaling is supported for the radial scale.

In opposite to QwtPlot the scales might be different from the view, that is displayed on the canvas. The view can be changed by zooming - f.e. by using QwtPolarPanner or QwtPolarMaginfier.

Definition at line 46 of file qwt_polar_plot.h.

Member Enumeration Documentation

enum QwtPolarPlot::LegendPosition

Position of the legend, relative to the canvas.

See also

insertLegend()

Enumerator
LeftLegend

The legend will be left from the canvas.

RightLegend

The legend will be right from the canvas.

BottomLegend

The legend will be below the canvas.

TopLegend

The legend will be between canvas and title.

ExternalLegend

External means that only the content of the legend will be handled by QwtPlot, but not its geometry. This might be interesting if an application wants to have a legend in an external window ( or on the canvas ).

Note

The legend is not painted by QwtPolarRenderer

Definition at line 59 of file qwt_polar_plot.h.

Constructor & Destructor Documentation

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

Constructor

Parameters

parent Parent widget

Definition at line 88 of file qwt_polar_plot.cpp.

QwtPolarPlot::QwtPolarPlot (const QwtText & title, QWidget * parent = NULL)

Constructor

Parameters

title Title text
parent Parent widget

Definition at line 99 of file qwt_polar_plot.cpp.

QwtPolarPlot::˜QwtPolarPlot () [virtual]

Destructor.

Definition at line 106 of file qwt_polar_plot.cpp.

Member Function Documentation

void QwtPolarPlot::autoRefresh () [slot]

Replots the plot if QwtPlot::autoReplot() is true.

Definition at line 847 of file qwt_polar_plot.cpp.

bool QwtPolarPlot::autoReplot () const

Returns

true if the autoReplot option is set.

Definition at line 348 of file qwt_polar_plot.cpp.

double QwtPolarPlot::azimuthOrigin () const

The azimuth origin is the angle where the azimuth scale shows the value 0.0.

Returns

Origin of the azimuth scale

See also

setAzimuthOrigin()

Definition at line 632 of file qwt_polar_plot.cpp.

QwtPolarCanvas * QwtPolarPlot::canvas ()

Returns

the plot’s canvas

Definition at line 914 of file qwt_polar_plot.cpp.

const QwtPolarCanvas * QwtPolarPlot::canvas () const

Returns

the plot’s canvas

Definition at line 920 of file qwt_polar_plot.cpp.

void QwtPolarPlot::drawCanvas (QPainter * painter, const QRectF &canvasRect) const [virtual]

Redraw the canvas.

Parameters

painter Painter used for drawing
canvasRect Contents rect of the canvas

Definition at line 930 of file qwt_polar_plot.cpp.

void QwtPolarPlot::drawItems (QPainter * painter, const QwtScaleMap &azimuthMap, const QwtScaleMap & radialMap, const QPointF & pole, doubleradius, const QRectF & canvasRect) const [protected], [virtual]

Redraw the canvas items.

Parameters

painter Painter used for drawing
azimuthMap Maps azimuth values to values related to 0.0, M_2PI
radialMap Maps radius values into painter coordinates.
pole Position of the pole in painter coordinates
radius Radius of the complete plot area in painter coordinates
canvasRect Contents rect of the canvas in painter coordinates

Definition at line 975 of file qwt_polar_plot.cpp.

bool QwtPolarPlot::event (QEvent * e) [override], [protected], [virtual]

Qt event handler. Handles QEvent::LayoutRequest and QEvent::PolishRequest

Parameters

e Qt Event

Returns

True, when the event was processed

Definition at line 762 of file qwt_polar_plot.cpp.

bool QwtPolarPlot::hasAutoScale (int scaleId) const

Returns

true if autoscaling is enabled

Parameters

scaleId Scale index

See also

setAutoScale()

Definition at line 386 of file qwt_polar_plot.cpp.

QwtPolarItem * QwtPolarPlot::infoToItem (const QVariant & itemInfo) const[virtual]

Identify the plot item according to an item info object, that has bee generated from itemToInfo(). The default implementation simply tries to unwrap a QwtPlotItem pointer:

if ( itemInfo.canConvert<QwtPlotItem *>() )
return qvariant_cast<QwtPlotItem *>( itemInfo );

Parameters

itemInfo Plot item

Returns

A plot item, when successful, otherwise a NULL pointer.

See also

itemToInfo()

Definition at line 1357 of file qwt_polar_plot.cpp.

void QwtPolarPlot::insertLegend (QwtAbstractLegend * legend,QwtPolarPlot::LegendPosition pos = RightLegend, double ratio = −1.0)

Insert a legend. If the position legend is QwtPolarPlot::LeftLegend or QwtPolarPlot::RightLegend the legend will be organized in one column from top to down. Otherwise the legend items will be placed in a table with a best fit number of columns from left to right.

If pos != QwtPolarPlot::ExternalLegend the plot widget will become parent of the legend. It will be deleted when the plot is deleted, or another legend is set with insertLegend().

Parameters

legend Legend
pos The legend’s position. For top/left position the number of columns will be limited to 1, otherwise it will be set to unlimited.
ratio Ratio between legend and the bounding rect of title, canvas and axes. The legend will be shrunk if it would need more space than the given ratio. The ratio is limited to ]0.0 .. 1.0]. In case of <= 0.0 it will be reset to the default ratio. The default vertical/horizontal ratio is 0.33/0.5.

See also

legend(), QwtPolarLayout::legendPosition(), QwtPolarLayout::setLegendPosition()

Definition at line 191 of file qwt_polar_plot.cpp.

void QwtPolarPlot::itemAttached (QwtPolarItem * plotItem, bool on) [signal]

A signal indicating, that an item has been attached/detached

Parameters

plotItem Plot item
on Attached/Detached

QVariant QwtPolarPlot::itemToInfo (QwtPolarItem * plotItem) const [virtual]

Build an information, that can be used to identify a plot item on the legend. The default implementation simply wraps the plot item into a QVariant object. When overloading itemToInfo() usually infoToItem() needs to reimplemeted too.

QVariant itemInfo;
qVariantSetValue( itemInfo, plotItem );

Parameters

plotItem Plot item

Definition at line 1282 of file qwt_polar_plot.cpp.

int QwtPolarPlot::plotMarginHint () const

Returns

Maximum of all item margin hints.

See also

QwtPolarItem::marginHint()

Definition at line 1095 of file qwt_polar_plot.cpp.

QRectF QwtPolarPlot::plotRect () const

The plot area depends on the size of the canvas and the zoom parameters.

Returns

Bounding rect of the plot area

Definition at line 1120 of file qwt_polar_plot.cpp.

QRectF QwtPolarPlot::plotRect (const QRectF & canvasRect) const

Calculate the bounding rect of the plot area. The plot area depends on the zoom parameters.

Parameters

canvasRect Rectangle of the canvas

Returns

Rectangle for displaying 100% of the plot

Definition at line 1133 of file qwt_polar_plot.cpp.

void QwtPolarPlot::replot () [virtual], [slot]

Redraw the plot. If the autoReplot option is not set (which is the default) or if any curves are attached to raw data, the plot has to be refreshed explicitly in order to make changes visible.

Returns

Scale engine for a specific scale

Parameters

scaleId Scale index

See also

setScaleEngine()

Returns

the maximum number of major ticks for a specified axis

Parameters

scaleId Scale index

See also

setScaleMaxMajor()

Definition at line 460 of file qwt_polar_plot.cpp.

int QwtPolarPlot::scaleMaxMinor (int scaleId) const

Returns

the maximum number of minor ticks for a specified axis

Parameters

scaleId Scale index

See also

setScaleMaxMinor()

Definition at line 423 of file qwt_polar_plot.cpp.

void QwtPolarPlot::setAutoReplot (bool enable = true)

Set or reset the autoReplot option. If the autoReplot option is set, the plot will be updated implicitly by manipulating member functions. Since this may be time-consuming, it is recommended to leave this option switched off and call replot() explicitly if necessary.

The autoReplot option is set to false by default, which means that the user has to call replot() in order to make changes visible.

Parameters

enable true or false. Defaults to true.

See also

replot()

Definition at line 342 of file qwt_polar_plot.cpp.

void QwtPolarPlot::setAutoScale (int scaleId)

Enable autoscaling. This member function is used to switch back to autoscaling mode after a fixed scale has been set. Autoscaling calculates a useful scale division from the bounding interval of all plot items with the QwtPolarItem::AutoScale attribute.

Change the plot’s title

Parameters

title New title

Definition at line 118 of file qwt_polar_plot.cpp.

void QwtPolarPlot::setTitle (const QwtText & title)

Change the plot’s title

Parameters

title New title

Definition at line 134 of file qwt_polar_plot.cpp.

QwtText QwtPolarPlot::title () const

Returns

the plot’s title

Definition at line 147 of file qwt_polar_plot.cpp.

QwtTextLabel * QwtPolarPlot::titleLabel ()

Returns

the plot’s title

Definition at line 153 of file qwt_polar_plot.cpp.

const QwtTextLabel * QwtPolarPlot::titleLabel () const

Returns

the plot’s title label.

Definition at line 159 of file qwt_polar_plot.cpp.

void QwtPolarPlot::unzoom ()

Unzoom the plot

Returns

Zoom factor

See also

zoom(), zoomPos()

Definition at line 691 of file qwt_polar_plot.cpp.

QwtPointPolar QwtPolarPlot::zoomPos () const

Returns

Zoom position

See also

zoom(), zoomFactor()

Definition at line 682 of file qwt_polar_plot.cpp.

Author

Generated automatically by Doxygen for Qwt User’s Guide from the source code.

Updated 2026-06-01 - jenkler.se | uex.se