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

#include <qwt_plot_spectrogram.h>

Inheritance diagram for QwtPlotSpectrogram:

Classes
class	PrivateData

Public Types
enum	DisplayMode { ImageMode = 0x01 , ContourMode = 0x02 }
	Display modes. More...

Public Types inherited from QwtPlotRasterItem
enum	CachePolicy { NoCache , PaintCache }
	Cache policy. More...

enum	PaintAttribute { PaintInDeviceResolution = 1 }
	Paint attributes. More...

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_PlotGraphic , Rtti_PlotTradingCurve , Rtti_PlotBarChart , Rtti_PlotMultiBarChart , Rtti_PlotShape , Rtti_PlotTextLabel , Rtti_PlotZone , Rtti_PlotVectorField , Rtti_PlotArrowMarker , Rtti_PlotBoxChart , 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...

Public Member Functions
	QwtPlotSpectrogram (const QString &title=QString())
	Constructor.

void	setDisplayMode (DisplayMode, bool on=true)
	Set a display mode.

bool	testDisplayMode (DisplayMode) const
	Test a display mode.

void	setData (QwtRasterData *data)
	Set the data to be displayed.

const QwtRasterData *	data () const
	Get the spectrogram data (const version)

QwtRasterData *	data ()
	Get the spectrogram data.

void	setColorMap (QwtColorMap *)
	Change the color map.

const QwtColorMap *	colorMap () const
	Get the color map used for mapping intensity values to colors.

void	setColorTableSize (int numColors)
	Limit the number of colors being used by the color map.

int	colorTableSize () const
	Get the color table size.

virtual QwtInterval	interval (Qt::Axis) const override
	Get the bounding interval for an axis.

virtual QRectF	pixelHint (const QRectF &) const override
	Get the pixel hint.

void	setDefaultContourPen (const QColor &, qreal width=0.0, Qt::PenStyle=Qt::SolidLine)
	Build and assign the default pen for the contour lines.

void	setDefaultContourPen (const QPen &)
	Set the default pen for the contour lines.

QPen	defaultContourPen () const
	Get the default contour pen.

virtual QPen	contourPen (double level) const
	Calculate the pen for a contour line.

void	setConrecFlag (QwtRasterData::ConrecFlag, bool on)
	Modify an attribute of the CONREC algorithm.

bool	testConrecFlag (QwtRasterData::ConrecFlag) const
	Test an attribute of the CONREC algorithm.

void	setContourLevels (const QList< double > &)
	Set the levels of the contour lines.

QList< double >	contourLevels () const
	Get the levels of the contour lines.

virtual int	rtti () const override
	Get the runtime type information.

virtual void	draw (QPainter *, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasRect) const override
	Draw the spectrogram.

Public Member Functions inherited from QwtPlotRasterItem
	QwtPlotRasterItem (const QString &title=QString())
	Constructor.

	QwtPlotRasterItem (const QwtText &title)

void	setPaintAttribute (PaintAttribute, bool on=true)
	Set a paint attribute.

bool	testPaintAttribute (PaintAttribute) const
	Test a paint attribute.

void	setAlpha (int alpha)
	Set an alpha value for the raster data.

int	alpha () const
	Get the alpha value of the raster item.

void	setCachePolicy (CachePolicy)
	Change the cache policy.

CachePolicy	cachePolicy () const
	Get the cache policy.

void	invalidateCache ()
	Invalidate the paint cache.

virtual QRectF	boundingRect () const override
	Get the bounding rectangle of the data.

Public Member Functions inherited from QwtPlotItem
	QwtPlotItem ()
	Default constructor.

	QwtPlotItem (const QString &title)
	Constructor with title as QString.

	QwtPlotItem (const QwtText &title)
	Constructor with title as QwtText.

virtual	~QwtPlotItem ()
	Destructor.

virtual void	attach (QwtPlot *plot)
	Attach the item to a plot.

void	detach ()
	Detach the item from the plot.

QwtPlot *	plot () const
	Get the plot the item is attached to.

void	setTitle (const QString &title)
	Set the title using a QString.

void	setTitle (const QwtText &title)
	Set the title using a QwtText.

const QwtText &	title () const
	Get the title.

void	setItemAttribute (ItemAttribute, bool on=true)
	Set an item attribute.

bool	testItemAttribute (ItemAttribute) const
	Test an item attribute.

void	setItemInterest (ItemInterest, bool on=true)
	Set an item interest.

bool	testItemInterest (ItemInterest) const
	Test an item interest.

void	setRenderHint (RenderHint, bool on=true)
	Set a render hint.

bool	testRenderHint (RenderHint) const
	Test a render hint.

void	setRenderThreadCount (uint numThreads)
	Set the number of render threads.

uint	renderThreadCount () const
	Get the number of render threads.

void	setLegendIconSize (const QSize &)
	Set the legend icon size.

QSize	legendIconSize () const
	Get the legend icon size.

double	z () const
	Get the z-value.

void	setZ (double z)
	Set the z-value.

void	show ()
	Show the item.

void	hide ()
	Hide the item.

virtual void	setVisible (bool)
	Set the visibility.

bool	isVisible () const
	Check if the item is visible.

void	setAxes (QwtAxisId xAxis, QwtAxisId yAxis)
	Set both axes.

void	setXAxis (QwtAxisId)
	Set the x-axis.

QwtAxisId	xAxis () const
	Get the x-axis.

void	setYAxis (QwtAxisId)
	Set the y-axis.

QwtAxisId	yAxis () const
	Get the y-axis.

virtual void	itemChanged ()
	Notify the plot that the item has changed.

virtual void	legendChanged ()
	Notify the item that the legend has changed.

virtual void	getCanvasMarginHint (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasRect, double &left, double &top, double &right, double &bottom) const
	Get margin hints for the canvas.

virtual void	updateScaleDiv (const QwtScaleDiv &, const QwtScaleDiv &)
	Update the item with new scale divisions.

virtual void	updateLegend (const QwtPlotItem *, const QList< QwtLegendData > &)
	Update the item with changes of the legend.

QRectF	scaleRect (const QwtScaleMap &, const QwtScaleMap &) const
	Calculate the scale rectangle.

QRectF	paintRect (const QwtScaleMap &, const QwtScaleMap &) const
	Calculate the paint rectangle.

virtual QList< QwtLegendData >	legendData () const
	Return legend data.

virtual QwtGraphic	legendIcon (int index, const QSizeF &) const
	Return a legend icon.

Protected Member Functions
virtual QImage	renderImage (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &area, const QSize &imageSize) const override
	Render the image.

virtual QSize	contourRasterSize (const QRectF &, const QRect &) const
	Calculate the contour raster size.

virtual QwtRasterData::ContourLines	renderContourLines (const QRectF &rect, const QSize &raster) const
	Render the contour lines.

virtual void	drawContourLines (QPainter *, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QwtRasterData::ContourLines &) const
	Draw the contour lines.

void	renderTile (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRect &tile, QImage *) const
	Render a tile.

Protected Member Functions inherited from QwtPlotRasterItem
virtual QwtScaleMap	imageMap (Qt::Orientation, const QwtScaleMap &map, const QRectF &area, const QSize &imageSize, double pixelSize) const
	Get the image map.

Protected Member Functions inherited from QwtPlotItem
QwtGraphic	defaultIcon (const QBrush &, const QSizeF &) const
	Create a default icon.

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

◆ DisplayMode

enum QwtPlotSpectrogram::DisplayMode

Display modes.

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

explicit

Constructor.

Sets the following item attributes:

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

The z value is initialized by 8.0.

Parameters

[in] title Title

See also: QwtPlotItem::setItemAttribute(), QwtPlotItem::setZ()

Destructor

Member Function Documentation

◆ colorMap()

const QwtColorMap * QwtPlotSpectrogram::colorMap ( ) const

Get the color map used for mapping intensity values to colors.

Returns: Color map used for mapping the intensity values to colors

See also: setColorMap()

◆ colorTableSize()

int QwtPlotSpectrogram::colorTableSize ( ) const

Get the color table size.

Returns: Size of the color table, 0 means not using a color table

See also: QwtColorMap::colorTable(), setColorTableSize()

◆ contourLevels()

QList< double > QwtPlotSpectrogram::contourLevels ( ) const

Get the levels of the contour lines.

Returns: Levels of the contour lines. The levels are sorted in increasing order.

See also: setContourLevels(), renderContourLines(), QwtRasterData::contourLines()

◆ contourPen()

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

[in] level Contour level

Returns: Pen for the contour line

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

See also: setDefaultContourPen(), setColorMap(), setContourLevels()

◆ contourRasterSize()

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

protectedvirtual

Calculate the contour raster size.

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()

◆ data() [1/2]

QwtRasterData * QwtPlotSpectrogram::data ( )

Get the spectrogram data.

Returns: Spectrogram data

See also: setData()

◆ data() [2/2]

const QwtRasterData * QwtPlotSpectrogram::data ( ) const

Get the spectrogram data (const version)

Returns: Spectrogram data

See also: setData()

◆ defaultContourPen()

QPen QwtPlotSpectrogram::defaultContourPen ( ) const

Get the default contour pen.

Returns: Default contour pen

See also: setDefaultContourPen()

◆ draw()

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

overridevirtual

Draw the spectrogram.

Parameters

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

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

Reimplemented from QwtPlotRasterItem.

◆ drawContourLines()

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

protectedvirtual

Draw the contour lines.

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()

◆ interval()

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

overridevirtual

Get the bounding interval for an axis.

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

Parameters

[in] axis X, Y, or Z axis

Returns: Bounding interval for the axis

See also: QwtRasterData::interval()

Reimplemented from QwtPlotRasterItem.

◆ pixelHint()

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

overridevirtual

Get the 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

[in] 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.

◆ renderContourLines()

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

protectedvirtual

Render the contour lines.

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()

◆ renderImage()

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

overrideprotectedvirtual

Render the image.

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.

◆ renderTile()

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

protected

Render a tile.

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

◆ rtti()

int QwtPlotSpectrogram::rtti ( ) const

overridevirtual

Get the runtime type information.

Returns: QwtPlotItem::Rtti_PlotSpectrogram

Reimplemented from QwtPlotItem.

◆ setColorMap()

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

[in] colorMap Color map

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

◆ setColorTableSize()

void QwtPlotSpectrogram::setColorTableSize ( int numColors )

Limit the number of colors being used by the color map.

When using a color table the mapping from the value into a color is usually faster as it can be done by simple lookups into a precalculated color table.

Setting a table size > 0 enables using a color table, while setting the size to 0 disables it. The default size = 0, and no color table is used.

Parameters

[in] numColors Number of colors. 0 means not using a color table

Note: The colorTableSize has no effect when using a color table of QwtColorMap::Indexed, where the size is always 256.

See also: QwtColorMap::colorTable(), colorTableSize()

◆ setConrecFlag()

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

Modify an attribute of the CONREC algorithm.

Used to calculate the contour lines.

Parameters

[in]	flag	CONREC flag
[in]	on	On/Off

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

◆ setContourLevels()

void QwtPlotSpectrogram::setContourLevels ( const QList< double > & levels )

Set the levels of the contour lines.

Parameters

[in] levels Values of the contour levels

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

Note: contourLevels returns the same levels but sorted.

◆ setData()

void QwtPlotSpectrogram::setData ( QwtRasterData * data )

Set the data to be displayed.

The ownership of the data is managed by QwtPlotSpectrogram.

Parameters

[in] data Spectrogram data

See also: data()

◆ setDefaultContourPen() [1/2]

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

[in]	color	Pen color
[in]	width	Pen width
[in]	style	Pen style

See also: defaultContourPen(), contourPen()

◆ setDefaultContourPen() [2/2]

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().

Parameters

[in] pen New default pen

See also: defaultContourPen(), contourPen()

◆ setDisplayMode()

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

Set a display mode.

The display mode controls how the raster data will be represented. The default setting enables ImageMode.

Parameters

[in]	mode	Display mode
[in]	on	On/Off

See also: DisplayMode, testDisplayMode()

◆ testConrecFlag()

bool QwtPlotSpectrogram::testConrecFlag ( QwtRasterData::ConrecFlag flag ) const

Test an attribute of the CONREC algorithm.

Used to calculate the contour lines. The default setting enables QwtRasterData::IgnoreAllVerticesOnLevel.

Parameters

[in] flag CONREC flag

Returns: true if enabled

See also: setConrecFlag(), renderContourLines(), QwtRasterData::contourLines()

◆ testDisplayMode()

bool QwtPlotSpectrogram::testDisplayMode ( DisplayMode mode ) const

Test a display mode.

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

Parameters

[in] mode Display mode

Returns: true if mode is enabled

The documentation for this class was generated from the following files:

/home/runner/work/QWT/QWT/src/plot/qwt_plot_spectrogram.h
/home/runner/work/QWT/QWT/src/plot/qwt_plot_spectrogram.cpp

Classes

Public Types

Public Member Functions

Protected Member Functions

Detailed Description

Member Enumeration Documentation

◆ DisplayMode

Constructor & Destructor Documentation

◆ QwtPlotSpectrogram()

Member Function Documentation

◆ colorMap()

◆ colorTableSize()

◆ contourLevels()

◆ contourPen()

◆ contourRasterSize()

◆ data() [1/2]

◆ data() [2/2]

◆ defaultContourPen()

◆ draw()

◆ drawContourLines()

◆ interval()

◆ pixelHint()

◆ renderContourLines()

◆ renderImage()

◆ renderTile()

◆ rtti()

◆ setColorMap()

◆ setColorTableSize()

◆ setConrecFlag()

◆ setContourLevels()

◆ setData()

◆ setDefaultContourPen() [1/2]

◆ setDefaultContourPen() [2/2]

◆ setDisplayMode()

◆ testConrecFlag()

◆ testDisplayMode()