Qwt User's Guide: QwtPlotSpectrogram Class Reference

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QwtPlotSpectrogram Class Reference

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

#include <qwt_plot_spectrogram.h>

Inheritance diagram for QwtPlotSpectrogram:
[legend]

List of all members.

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.

spectrogram3.png
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:
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::testConrecAttribute ( QwtRasterData::ConrecAttribute  attribute  )  const

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

Parameters:
attribute CONREC attribute
Returns:
true, is enabled
See also:
setConrecAttribute(), 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
Generated on Wed Sep 2 18:37:26 2009 for Qwt User's Guide by  doxygen 1.6.1
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