QwtPlotSpectrogram

Section: C Library Functions (3) Updated: 22 Mar 2009 Local index Up

NAME

QwtPlotSpectrogram - A plot item, which displays a spectrogram.

SYNOPSIS

#include <qwt_plot_spectrogram.h>

Inherits QwtPlotRasterItem.

Public Types

enum DisplayMode { ImageMode = 1, ContourMode = 2 }

Public Member Functions

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

virtual ~QwtPlotSpectrogram ()

void setDisplayMode (DisplayMode, bool on=true)

bool testDisplayMode (DisplayMode) const

void setData (const QwtRasterData &data)

const QwtRasterData & data () const

void setColorMap (const QwtColorMap &)

const QwtColorMap & colorMap () const

virtual QwtDoubleRect boundingRect () const

virtual QSize rasterHint (const QwtDoubleRect &) const

void setDefaultContourPen (const QPen &)

QPen defaultContourPen () const

virtual QPen contourPen (double level) const

void setConrecAttribute (QwtRasterData::ConrecAttribute, bool on)

bool testConrecAttribute (QwtRasterData::ConrecAttribute) const

void setContourLevels (const QwtValueList &)

QwtValueList contourLevels () const

virtual int rtti () const

virtual void draw (QPainter *p, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRect &rect) const

Protected Member Functions

virtual QImage renderImage (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QwtDoubleRect &rect) const

virtual QSize contourRasterSize (const QwtDoubleRect &, const QRect &) const

virtual QwtRasterData::ContourLines renderContourLines (const QwtDoubleRect &rect, const QSize &raster) const

virtual void drawContourLines (QPainter *p, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QwtRasterData::ContourLines &lines) const

Detailed Description

A plot item, which displays a spectrogram.

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

In ContourMode contour lines are painted for the contour levels.

See also:

: QwtRasterData, QwtColorMap

Member Enumeration Documentation

enum QwtPlotSpectrogram::DisplayMode

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

•: ImageMode

The values are mapped to colors using a color map.
•: ContourMode

The data is displayed using contour lines

When both modes are enabled the contour lines are painted on top of the spectrogram. The default setting enables ImageMode.

See also:

: setDisplayMode(), testDisplayMode()

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()

QwtPlotSpectrogram::~QwtPlotSpectrogram () [virtual]

Destructor.

Member Function Documentation

QwtDoubleRect QwtPlotSpectrogram::boundingRect () const [virtual]

Returns:

: Bounding rect of the data

See also:

: QwtRasterData::boundingRect()

Reimplemented from QwtPlotItem.

const QwtColorMap & QwtPlotSpectrogram::colorMap () const

Returns:

: Color Map used for mapping the intensity values to colors

See also:

: setColorMap()

QwtValueList QwtPlotSpectrogram::contourLevels () const

Return the 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 QwtDoubleRect & area, const QRect & rect) const [protected, virtual]

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

A larger size will improve the precisision 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 data().rasterHint().

Parameters:

: area Rect, where to calculate the contour lines
rect Rect 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()

QPen QwtPlotSpectrogram::defaultContourPen () const

Returns:

: Default contour pen

See also:

: setDefaultContourPen()

void QwtPlotSpectrogram::draw (QPainter * painter, const QwtScaleMap & xMap, const QwtScaleMap & yMap, const QRect & 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 rect 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 [protected, virtual]

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()

QSize QwtPlotSpectrogram::rasterHint (const QwtDoubleRect & rect) const [virtual]

Returns the recommended raster for a given rect.

F.e the raster hint is used to limit the resolution of the image that is rendered.

Parameters:

: rect Rect for the raster hint

Returns:

: data().rasterHint(rect)

Reimplemented from QwtPlotRasterItem.

QwtRasterData::ContourLines QwtPlotSpectrogram::renderContourLines (const QwtDoubleRect & rect, const QSize & raster) const [protected, virtual]

Calculate contour lines

Parameters:

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

See also:

: contourLevels(), setConrecAttribute(), QwtRasterData::contourLines()

QImage QwtPlotSpectrogram::renderImage (const QwtScaleMap & xMap, const QwtScaleMap & yMap, const QwtDoubleRect & area) 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:

: xMap X-Scale Map
yMap Y-Scale Map
area Area that should be rendered in scale coordinates.

Returns:

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

See also:

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

Implements QwtPlotRasterItem.

int QwtPlotSpectrogram::rtti () const [virtual]

Returns:

: QwtPlotItem::Rtti_PlotSpectrogram

Reimplemented from QwtPlotItem.

void QwtPlotSpectrogram::setColorMap (const 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::setConrecAttribute (QwtRasterData::ConrecAttribute attribute, bool on)

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

Parameters:

: attribute CONREC attribute
on On/Off

See also:

: testConrecAttribute(), renderContourLines(), QwtRasterData::contourLines()

void QwtPlotSpectrogram::setContourLevels (const QwtValueList & 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 (const QwtRasterData & data)

Set the data to be displayed

Parameters:

: data Spectrogram Data

See also:

: data()

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: