QwtPolarSpectrogram - An item, which displays a spectrogram.

NAME

QwtPolarSpectrogram − An item, which displays a spectrogram.

SYNOPSIS

#include <qwt_polar_spectrogram.h>

Inherits QwtPolarItem.

Public Types

enum PaintAttribute { ApproximatedAtan = 0x01 }
typedef QFlags< PaintAttribute > PaintAttributes

Public Types inherited from QwtPolarItem

enum RttiValues { Rtti_PolarItem = 0, Rtti_PolarGrid, Rtti_PolarMarker, Rtti_PolarCurve, Rtti_PolarSpectrogram, Rtti_PolarUserItem = 1000 }
Runtime type information.
enum ItemAttribute { Legend = 0x01, AutoScale = 0x02 }
Plot Item Attributes.
enum RenderHint { RenderAntialiased = 0x01 }
Render hints.
typedef QFlags< ItemAttribute > ItemAttributes
typedef QFlags< RenderHint > RenderHints

Public Member Functions

QwtPolarSpectrogram ()
Constructor.
virtual ˜QwtPolarSpectrogram ()
Destructor.
void setData (QwtRasterData *data)
const QwtRasterData * data () const
void setColorMap (QwtColorMap *)
const QwtColorMap * colorMap () const
void setPaintAttribute (PaintAttribute, bool on=true)
bool testPaintAttribute (PaintAttribute) const
virtual int rtti () const override
virtual void draw (QPainter *painter, const QwtScaleMap &azimuthMap, const QwtScaleMap &radialMap, const QPointF &pole, double radius, const QRectF &canvasRect) const override
virtual QwtInterval boundingInterval (int scaleId) const override

Public Member Functions inherited from QwtPolarItem

QwtPolarItem (const QwtText &title=QwtText())
virtual ˜QwtPolarItem ()
Destroy the QwtPolarItem.
void attach (QwtPolarPlot *plot)
Attach the item to a plot.
void detach ()
This method detaches a QwtPolarItem from the QwtPolarPlot it has been associated with.
QwtPolarPlot * plot () const
void setTitle (const QString &title)
void setTitle (const QwtText &title)
const QwtText & title () const
void setItemAttribute (ItemAttribute, bool on=true)
bool testItemAttribute (ItemAttribute) const
void setRenderHint (RenderHint, bool on=true)
bool testRenderHint (RenderHint) const
void setRenderThreadCount (uint numThreads)
uint renderThreadCount () const
double z () const
void setZ (double z)
Set the z value.
void show ()
Show the item.
void hide ()
Hide the item.
virtual void setVisible (bool)
bool isVisible () const
virtual void itemChanged ()
virtual void legendChanged ()
virtual void updateScaleDiv (const QwtScaleDiv &, const QwtScaleDiv &, const QwtInterval &)
Update the item to changes of the axes scale division.
virtual int marginHint () const
void setLegendIconSize (const QSize &)
QSize legendIconSize () const
virtual QList< QwtLegendData > legendData () const
Return all information, that is needed to represent the item on the legend.
virtual QwtGraphic legendIcon (int index, const QSizeF &) const

Protected Member Functions

virtual QImage renderImage (const QwtScaleMap &azimuthMap, const QwtScaleMap &radialMap, const QPointF &pole, const QRect &rect) const
Render an image from the data and color map.
virtual void renderTile (const QwtScaleMap &azimuthMap, const QwtScaleMap &radialMap, const QPointF &pole, const QPoint &imagePos, const QRect &tile, QImage *image) const
Render a sub-rectangle of an image.

Detailed Description

An item, which displays a spectrogram.

A spectrogram displays 3-dimensional data, where the 3rd dimension ( the intensity ) is displayed using colors. The colors are calculated from the values using a color map.

See also

QwtRasterData, QwtColorMap

Definition at line 28 of file qwt_polar_spectrogram.h.

Member Typedef Documentation

typedef QFlags<PaintAttribute > QwtPolarSpectrogram::PaintAttributes

An ORed combination of PaintAttribute values.

Definition at line 47 of file qwt_polar_spectrogram.h.

Member Enumeration Documentation

enum QwtPolarSpectrogram::PaintAttribute

Attributes to modify the drawing algorithm. The default setting disables ApproximatedAtan

See also

setPaintAttribute(), testPaintAttribute()

Enumerator
ApproximatedAtan

Use qwtFastAtan2 instead of atan2 for translating widget into polar coordinates.

Definition at line 37 of file qwt_polar_spectrogram.h.

Constructor & Destructor Documentation

QwtPolarSpectrogram::QwtPolarSpectrogram () [explicit]

Constructor.

Definition at line 55 of file qwt_polar_spectrogram.cpp.

QwtPolarSpectrogram::˜QwtPolarSpectrogram () [virtual]

Destructor.

Definition at line 67 of file qwt_polar_spectrogram.cpp.

Member Function Documentation

QwtInterval QwtPolarSpectrogram::boundingInterval (int scaleId) const[override], [virtual]

Interval, that is necessary to display the item This interval can be useful for operations like clipping or autoscaling

Parameters

scaleId Scale index

Returns

bounding interval ( == position )

See also

position()

Reimplemented from QwtPolarItem.

Definition at line 440 of file qwt_polar_spectrogram.cpp.

const QwtColorMap * QwtPolarSpectrogram::colorMap () const

Returns

Color Map used for mapping the intensity values to colors

See also

setColorMap()

Definition at line 134 of file qwt_polar_spectrogram.cpp.

const QwtRasterData * QwtPolarSpectrogram::data () const

Returns

Spectrogram data

See also

setData()

Definition at line 103 of file qwt_polar_spectrogram.cpp.

void QwtPolarSpectrogram::draw (QPainter * painter, const QwtScaleMap &azimuthMap, const QwtScaleMap & radialMap, const QPointF & pole, doubleradius, const QRectF & canvasRect) const [override], [virtual]

Draw the spectrogram

Parameters

painter Painter
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

Implements QwtPolarItem.

Definition at line 174 of file qwt_polar_spectrogram.cpp.

QImage QwtPolarSpectrogram::renderImage (const QwtScaleMap & azimuthMap,const QwtScaleMap & radialMap, const QPointF & pole, const QRect &rect) const [protected], [virtual]

Render an image from the data and color map. The area is translated into a rect of the paint device. For each pixel of this rect the intensity is mapped into a color.

Parameters

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
rect Target rectangle of the image in painter coordinates

Returns

A QImage::Format_Indexed8 or QImage::Format_ARGB32 depending on the color map.

See also

QwtRasterData::intensity(), QwtColorMap::rgb(), QwtColorMap::colorIndex()

Definition at line 232 of file qwt_polar_spectrogram.cpp.

void QwtPolarSpectrogram::renderTile (const QwtScaleMap & azimuthMap, constQwtScaleMap & radialMap, const QPointF & pole, const QPoint & imagePos,const QRect & tile, QImage * image) const [protected], [virtual]

Render a sub-rectangle of an image. renderTile() is called by renderImage() to render different parts of the image by concurrent threads.

Parameters

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
imagePos Top/left position of the image in painter coordinates
tile Sub-rectangle of the tile in painter coordinates
image Image to be rendered

See also

setRenderThreadCount()

Note

renderTile needs to be reentrant

Definition at line 340 of file qwt_polar_spectrogram.cpp.

int QwtPolarSpectrogram::rtti () const [override], [virtual]

Returns

QwtPolarItem::Rtti_PolarSpectrogram

Reimplemented from QwtPolarItem.

Definition at line 73 of file qwt_polar_spectrogram.cpp.

void QwtPolarSpectrogram::setColorMap (QwtColorMap * colorMap)

Change the color map

Often it is useful to display the mapping between intensities and colors as an additional plot axis, showing a color bar.

Parameters

colorMap Color Map

See also

colorMap(), QwtScaleWidget::setColorBarEnabled(), QwtScaleWidget::setColorMap()

Definition at line 119 of file qwt_polar_spectrogram.cpp.

void QwtPolarSpectrogram::setData (QwtRasterData * data)

Set the data to be displayed

Parameters

data Spectrogram Data

See also

data()

Warning

QwtRasterData::initRaster() is called each time before the image is rendered, but without any useful parameters. Also QwtRasterData::rasterHint() is not used.

Definition at line 88 of file qwt_polar_spectrogram.cpp.

void QwtPolarSpectrogram::setPaintAttribute (PaintAttribute attribute, boolon = true)

Specify an attribute how to draw the curve

Parameters

attribute Paint attribute
on On/Off

See also

testPaintAttribute()

Definition at line 146 of file qwt_polar_spectrogram.cpp.

bool QwtPolarSpectrogram::testPaintAttribute (PaintAttribute attribute)const

Parameters

attribute Paint attribute

Returns

True, when attribute has been set

See also

setPaintAttribute()

Definition at line 159 of file qwt_polar_spectrogram.cpp.

Author

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