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
           Display modes.

   Public Member Functions
       QwtPlotSpectrogram (const QString &title=QString())
       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.
       void setDefaultContourPen (const QColor &, qreal width=0.0, Qt::PenStyle=Qt::SolidLine)
       void setDefaultContourPen (const QPen &)
           Set the default pen for the contour lines.
       QPen defaultContourPen () const
       virtual QPen contourPen (double level) const
           Calculate the pen for a contour line.
       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 *, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const
           QRectF &canvasRect) const
           Draw the spectrogram.

   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.
       virtual QSize contourRasterSize (const QRectF &, const QRect &) const
           Return the raster to be used by the CONREC contour algorithm.
       virtual QwtRasterData::ContourLines renderContourLines (const QRectF &rect, const QSize
           &raster) const
       virtual void drawContourLines (QPainter *, const QwtScaleMap &xMap, const QwtScaleMap
           &yMap, const QwtRasterData::ContourLines &) const
       void renderTile (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRect &tile,
           QImage *) const
           Render a tile of an image.

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()) [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
       [protected],  [virtual]
       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 [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::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 [protected],  [virtual]
       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 [protected],  [virtual]
       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

Author

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