QwtPlotSpectrogram Class Reference

A plot item, which displays a spectrogram. More...

#include <qwt_plot_spectrogram.h>

Inheritance diagram for QwtPlotSpectrogram:

Public Types
enum	DisplayMode { ImageMode = 0x01, ContourMode = 0x02 }
typedef QFlags< DisplayMode >	DisplayModes
	Display modes.
Public Types inherited from QwtPlotRasterItem
enum	CachePolicy { NoCache, PaintCache }
	Cache policy The default policy is NoCache. More...
enum	PaintAttribute { PaintInDeviceResolution = 1 }
typedef QFlags< PaintAttribute >	PaintAttributes
	Paint attributes.
Public Types inherited from QwtPlotItem
enum	RttiValues {   Rtti_PlotItem = 0, Rtti_PlotGrid, Rtti_PlotScale, Rtti_PlotLegend,   Rtti_PlotMarker, Rtti_PlotCurve, Rtti_PlotSpectroCurve, Rtti_PlotIntervalCurve,   Rtti_PlotHistogram, Rtti_PlotSpectrogram, Rtti_PlotSVG, Rtti_PlotTradingCurve,   Rtti_PlotBarChart, Rtti_PlotMultiBarChart, Rtti_PlotShape, Rtti_PlotTextLabel,   Rtti_PlotZone, Rtti_PlotUserItem = 1000 }
	Runtime type information. More...
enum	ItemAttribute { Legend = 0x01, AutoScale = 0x02, Margins = 0x04 }
	Plot Item Attributes. More...
enum	ItemInterest { ScaleInterest = 0x01, LegendInterest = 0x02 }
	Plot Item Interests. More...
enum	RenderHint { RenderAntialiased = 0x1 }
	Render hints. More...
typedef QFlags< ItemAttribute >	ItemAttributes
	Plot Item Attributes.
typedef QFlags< ItemInterest >	ItemInterests
	Plot Item Interests.
typedef QFlags< RenderHint >	RenderHints
	Render hints.

Public Member Functions
	QwtPlotSpectrogram (const QString &title=QString::null)
virtual	~QwtPlotSpectrogram ()
	Destructor.
void	setDisplayMode (DisplayMode, bool on=true)
bool	testDisplayMode (DisplayMode) const
void	setData (QwtRasterData *data)
const QwtRasterData *	data () const
QwtRasterData *	data ()
void	setColorMap (QwtColorMap *)
const QwtColorMap *	colorMap () const
virtual QwtInterval	interval (Qt::Axis) const
virtual QRectF	pixelHint (const QRectF &) const
	Pixel hint. More...
void	setDefaultContourPen (const QColor &, qreal width=0.0, Qt::PenStyle=Qt::SolidLine)
void	setDefaultContourPen (const QPen &)
	Set the default pen for the contour lines. More...
QPen	defaultContourPen () const
virtual QPen	contourPen (double level) const
	Calculate the pen for a contour line. More...
void	setConrecFlag (QwtRasterData::ConrecFlag, bool on)
bool	testConrecFlag (QwtRasterData::ConrecFlag) const
void	setContourLevels (const QList< double > &)
QList< double >	contourLevels () const
virtual int	rtti () const
virtual void	draw (QPainter *p, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &rect) const
	Draw the spectrogram. More...
Public Member Functions inherited from QwtPlotRasterItem
	QwtPlotRasterItem (const QString &title=QString::null)
	Constructor.
	QwtPlotRasterItem (const QwtText &title)
	Constructor.
virtual	~QwtPlotRasterItem ()
	Destructor.
void	setPaintAttribute (PaintAttribute, bool on=true)
bool	testPaintAttribute (PaintAttribute) const
void	setAlpha (int alpha)
	Set an alpha value for the raster data. More...
int	alpha () const
void	setCachePolicy (CachePolicy)
CachePolicy	cachePolicy () const
void	invalidateCache ()
virtual QRectF	boundingRect () const
Public Member Functions inherited from QwtPlotItem
	QwtPlotItem (const QwtText &title=QwtText())
virtual	~QwtPlotItem ()
	Destroy the QwtPlotItem.
void	attach (QwtPlot *plot)
	Attach the item to a plot. More...
void	detach ()
	This method detaches a QwtPlotItem from any QwtPlot it has been associated with. More...
QwtPlot *	plot () const
	Return attached plot.
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	setItemInterest (ItemInterest, bool on=true)
bool	testItemInterest (ItemInterest) const
void	setRenderHint (RenderHint, bool on=true)
bool	testRenderHint (RenderHint) const
void	setRenderThreadCount (uint numThreads)
uint	renderThreadCount () const
void	setLegendIconSize (const QSize &)
QSize	legendIconSize () const
double	z () const
void	setZ (double z)
	Set the z value. More...
void	show ()
	Show the item.
void	hide ()
	Hide the item.
virtual void	setVisible (bool)
bool	isVisible () const
void	setAxes (int xAxis, int yAxis)
void	setXAxis (int axis)
int	xAxis () const
	Return xAxis.
void	setYAxis (int axis)
int	yAxis () const
	Return yAxis.
virtual void	itemChanged ()
virtual void	legendChanged ()
virtual void	getCanvasMarginHint (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasSize, double &left, double &top, double &right, double &bottom) const
	Calculate a hint for the canvas margin. More...
virtual void	updateScaleDiv (const QwtScaleDiv &, const QwtScaleDiv &)
	Update the item to changes of the axes scale division. More...
virtual void	updateLegend (const QwtPlotItem *, const QList< QwtLegendData > &)
	Update the item to changes of the legend info. More...
QRectF	scaleRect (const QwtScaleMap &, const QwtScaleMap &) const
	Calculate the bounding scale rectangle of 2 maps. More...
QRectF	paintRect (const QwtScaleMap &, const QwtScaleMap &) const
	Calculate the bounding paint rectangle of 2 maps. More...
virtual QList< QwtLegendData >	legendData () const
	Return all information, that is needed to represent the item on the legend. More...
virtual QwtGraphic	legendIcon (int index, const QSizeF &) const

Protected Member Functions
virtual QImage	renderImage (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &area, const QSize &imageSize) const
	Render an image from data and color map. More...
virtual QSize	contourRasterSize (const QRectF &, const QRect &) const
	Return the raster to be used by the CONREC contour algorithm. More...
virtual QwtRasterData::ContourLines	renderContourLines (const QRectF &rect, const QSize &raster) const
virtual void	drawContourLines (QPainter *p, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QwtRasterData::ContourLines &lines) const
void	renderTile (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRect &imageRect, QImage *image) const
	Render a tile of an image. More...
Protected Member Functions inherited from QwtPlotRasterItem
virtual QwtScaleMap	imageMap (Qt::Orientation, const QwtScaleMap &map, const QRectF &area, const QSize &imageSize, double pixelSize) const
	Calculate a scale map for painting to an image. More...
Protected Member Functions inherited from QwtPlotItem
QwtGraphic	defaultIcon (const QBrush &, const QSizeF &) const
	Return a default icon from a brush. More...

Detailed Description

A plot 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.

On multi-core systems the performance of the image composition can often be improved by dividing the area into tiles - each of them rendered in a different thread ( see QwtPlotItem::setRenderThreadCount() ).

In ContourMode contour lines are painted for the contour levels.

See also

QwtRasterData, QwtColorMap, QwtPlotItem::setRenderThreadCount()

Member Enumeration Documentation

enum QwtPlotSpectrogram::DisplayMode

The display mode controls how the raster data will be represented.

See also

setDisplayMode(), testDisplayMode()

Enumerator
ImageMode	The values are mapped to colors using a color map.
ContourMode	The data is displayed using contour lines.

Constructor & Destructor Documentation

QwtPlotSpectrogram::QwtPlotSpectrogram ( const QString &  title = QString::null )

explicit

Sets the following item attributes:

• QwtPlotItem::AutoScale: true
• QwtPlotItem::Legend: false

The z value is initialized by 8.0.

Parameters

title

Title

See also

QwtPlotItem::setItemAttribute(), QwtPlotItem::setZ()

Member Function Documentation

const QwtColorMap * QwtPlotSpectrogram::colorMap

(

)

const

Returns

Color Map used for mapping the intensity values to colors

See also

setColorMap()

QList< double > QwtPlotSpectrogram::contourLevels

(

)

const

Returns

Levels of the contour lines.

The levels are sorted in increasing order.

See also

contourLevels(), renderContourLines(), QwtRasterData::contourLines()

QPen QwtPlotSpectrogram::contourPen ( double  level ) const

virtual

Calculate the pen for a contour line.

The color of the pen is the color for level calculated by the color map

Parameters

level

Contour level

Returns

Pen for the contour line

Note

contourPen is only used if defaultContourPen().style() == Qt::NoPen

See also

setDefaultContourPen(), setColorMap(), setContourLevels()

QSize QwtPlotSpectrogram::contourRasterSize ( const QRectF &  area, const QRect &  rect  ) const

protectedvirtual

Return the raster to be used by the CONREC contour algorithm.

A larger size will improve the precision of the CONREC algorithm, but will slow down the time that is needed to calculate the lines.

The default implementation returns rect.size() / 2 bounded to the resolution depending on pixelSize().

Parameters

area	Rectangle, where to calculate the contour lines
rect	Rectangle in pixel coordinates, where to paint the contour lines

Returns

Raster to be used by the CONREC contour algorithm.

Note

The size will be bounded to rect.size().

See also

drawContourLines(), QwtRasterData::contourLines()

const QwtRasterData * QwtPlotSpectrogram::data

(

)

const

Returns

Spectrogram data

See also

setData()

QwtRasterData * QwtPlotSpectrogram::data

(

)

Returns

Spectrogram data

See also

setData()

QPen QwtPlotSpectrogram::defaultContourPen

(

)

const

Returns

Default contour pen

See also

setDefaultContourPen()

void QwtPlotSpectrogram::draw ( QPainter *  painter, const QwtScaleMap &  xMap, const QwtScaleMap &  yMap, const QRectF &  canvasRect  ) const

virtual

Draw the spectrogram.

Parameters

painter	Painter
xMap	Maps x-values into pixel coordinates.
yMap	Maps y-values into pixel coordinates.
canvasRect	Contents rectangle of the canvas in painter coordinates

See also

setDisplayMode(), renderImage(), QwtPlotRasterItem::draw(), drawContourLines()

Reimplemented from QwtPlotRasterItem.

void QwtPlotSpectrogram::drawContourLines ( QPainter *  painter, const QwtScaleMap &  xMap, const QwtScaleMap &  yMap, const QwtRasterData::ContourLines &  contourLines  ) const

protectedvirtual

Paint the contour lines

Parameters

painter	Painter
xMap	Maps x-values into pixel coordinates.
yMap	Maps y-values into pixel coordinates.
contourLines	Contour lines

See also

renderContourLines(), defaultContourPen(), contourPen()

QwtInterval QwtPlotSpectrogram::interval ( Qt::Axis  axis ) const

virtual

Returns

Bounding interval for an axis

The default implementation returns the interval of the associated raster data object.

Parameters

axis	X, Y, or Z axis

See also

QwtRasterData::interval()

Reimplemented from QwtPlotRasterItem.

QRectF QwtPlotSpectrogram::pixelHint ( const QRectF &  area ) const

virtual

Pixel hint.

The geometry of a pixel is used to calculated the resolution and alignment of the rendered image.

The default implementation returns data()->pixelHint( rect );

Parameters

area	In most implementations the resolution of the data doesn't depend on the requested area.

Returns

Bounding rectangle of a pixel

See also

QwtPlotRasterItem::pixelHint(), QwtRasterData::pixelHint(), render(), renderImage()

Reimplemented from QwtPlotRasterItem.

QwtRasterData::ContourLines QwtPlotSpectrogram::renderContourLines ( const QRectF &  rect, const QSize &  raster  ) const

protectedvirtual

Calculate contour lines

Parameters

rect	Rectangle, where to calculate the contour lines
raster	Raster, used by the CONREC algorithm

Returns

Calculated contour lines

See also

contourLevels(), setConrecFlag(), QwtRasterData::contourLines()

QImage QwtPlotSpectrogram::renderImage ( const QwtScaleMap &  xMap, const QwtScaleMap &  yMap, const QRectF &  area, const QSize &  imageSize  ) const

protectedvirtual

Render an image from data and color map.

For each pixel of area the value is mapped into a color.

Parameters

xMap	X-Scale Map
yMap	Y-Scale Map
area	Requested area for the image in scale coordinates
imageSize	Size of the requested image

Returns

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

See also

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

Implements QwtPlotRasterItem.

void QwtPlotSpectrogram::renderTile ( const QwtScaleMap &  xMap, const QwtScaleMap &  yMap, const QRect &  tile, QImage *  image  ) const

protected

Render a tile of an image.

Rendering in tiles can be used to composite an image in parallel threads.

Parameters

xMap	X-Scale Map
yMap	Y-Scale Map
tile	Geometry of the tile in image coordinates
image	Image to be rendered

int QwtPlotSpectrogram::rtti ( ) const

virtual

Returns

QwtPlotItem::Rtti_PlotSpectrogram

Reimplemented from QwtPlotItem.

void QwtPlotSpectrogram::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()

void QwtPlotSpectrogram::setConrecFlag	(	QwtRasterData::ConrecFlag	flag,
		bool	on
	)

Modify an attribute of the CONREC algorithm, used to calculate the contour lines.

Parameters

flag	CONREC flag
on	On/Off

See also

testConrecFlag(), renderContourLines(), QwtRasterData::contourLines()

void QwtPlotSpectrogram::setContourLevels

(

const QList< double > &

levels

)

Set the levels of the contour lines

Parameters

levels

Values of the contour levels

See also

contourLevels(), renderContourLines(), QwtRasterData::contourLines()

Note

contourLevels returns the same levels but sorted.

void QwtPlotSpectrogram::setData

(

QwtRasterData *

data

)

Set the data to be displayed

Parameters

data	Spectrogram Data

See also

data()

void QwtPlotSpectrogram::setDefaultContourPen	(	const QColor &	color,
		qreal	width = 0.0,
		Qt::PenStyle	style = Qt::SolidLine
	)

Build and assign the default pen for the contour lines

In Qt5 the default pen width is 1.0 ( 0.0 in Qt4 ) what makes it non cosmetic ( see QPen::isCosmetic() ). This method has been introduced to hide this incompatibility.

Parameters

color	Pen color
width	Pen width
style	Pen style

See also

pen(), brush()

void QwtPlotSpectrogram::setDefaultContourPen

(

const QPen &

pen

)

Set the default pen for the contour lines.

If the spectrogram has a valid default contour pen a contour line is painted using the default contour pen. Otherwise (pen.style() == Qt::NoPen) the pen is calculated for each contour level using contourPen().

See also

defaultContourPen(), contourPen()

void QwtPlotSpectrogram::setDisplayMode	(	DisplayMode	mode,
		bool	on = true
	)

The display mode controls how the raster data will be represented.

Parameters

mode	Display mode
on	On/Off

The default setting enables ImageMode.

See also

DisplayMode, displayMode()

bool QwtPlotSpectrogram::testConrecFlag

(

QwtRasterData::ConrecFlag

flag

)

const

Test an attribute of the CONREC algorithm, used to calculate the contour lines.

Parameters

flag	CONREC flag

Returns

true, is enabled

The default setting enables QwtRasterData::IgnoreAllVerticesOnLevel

See also

setConrecClag(), renderContourLines(), QwtRasterData::contourLines()

bool QwtPlotSpectrogram::testDisplayMode

(

DisplayMode

mode

)

const

The display mode controls how the raster data will be represented.

Parameters

mode	Display mode

Returns

true if mode is enabled