Qwt User's Guide

NAME¶

QwtPlotSpectrogram -

A plot item, which displays a spectrogram.

SYNOPSIS¶

#include <qwt_plot_spectrogram.h>

Inherits QwtPlotRasterItem.

Public Types¶

enum DisplayMode { ImageMode = 0x01, ContourMode = 0x02 }

typedef QFlags< DisplayMode > DisplayModes

Public Member Functions¶

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

virtual ~QwtPlotSpectrogram ()

void setRenderThreadCount (uint numThreads)

uint renderThreadCount () const

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

void setDefaultContourPen (const QPen &)

QPen defaultContourPen () const

virtual QPen contourPen (double level) const

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

Protected Member Functions¶

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

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

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

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 Typedef Documentation¶

typedef QFlags<DisplayMode> QwtPlotSpectrogram::DisplayModes¶

Display modes.

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()

QwtPlotSpectrogram::~QwtPlotSpectrogram () [virtual]¶

Destructor.

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¶

Return the levels of the contour lines. The levels are sorted in increasing order.

See also:

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

QPen QwtPlotSpectrogram::contourPen (doublelevel) 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 [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 the resolution depending on pixelSize().

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()

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 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()

QwtInterval QwtPlotSpectrogram::interval (Qt::Axisaxis) 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 [protected, virtual] Calculate contour lines¶

Parameters:

rect Rectangle, where to calculate the contour lines

raster Raster, used by the CONREC algorithm

See also:

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

QImage QwtPlotSpectrogram::renderImage (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &area, const QSize &imageSize) const [protected, virtual]¶

Render an image from data and color map. For each pixel of rect 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.

uint QwtPlotSpectrogram::renderThreadCount () const Returns:¶

Number of threads to be used for rendering. If numThreads is set to 0, the system specific ideal thread count is used.

Warning:

Rendering in multiple threads is only supported for Qt >= 4.4

See also:

setRenderThreadCount(), renderImage(), renderTile()

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::ConrecFlagflag, boolon) 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 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 (DisplayModemode, boolon = 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()

void QwtPlotSpectrogram::setRenderThreadCount (uintnumThreads) Rendering an image from the raster data can often be done parallel on a multicore system.¶

Parameters:

numThreads Number of threads to be used for rendering. If numThreads is set to 0, the system specific ideal thread count is used.

The default thread count is 1 ( = no additional threads )

Warning:

Rendering in multiple threads is only supported for Qt >= 4.4

See also:

renderThreadCount(), renderImage(), renderTile()

bool QwtPlotSpectrogram::testConrecFlag (QwtRasterData::ConrecFlagflag) const Test an attribute of the CONREC algorithm, used to calculate the contour lines.¶

Parameters:

flag CONREC flag

Returns:

true, is enabled

See also:

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

bool QwtPlotSpectrogram::testDisplayMode (DisplayModemode) const The display mode controls how the raster data will be represented.¶

Parameters:

mode Display mode

Returns:

true if mode is enabled

Author¶

Generated automatically by Doxygen for Qwt User's Guide from the source code.

Fri Apr 15 2011

Version 6.0.0

Source file:	QwtPlotSpectrogram.3.en.gz (from libqwt-doc 6.0.0-1.2)
Source last updated:	2012-05-09T19:30:30Z
Converted to HTML:	2017-06-07T16:54:57Z