QwtPlotSpectrogram - Man Page

enum CachePolicy { NoCache, PaintCache, ScreenCache }
enum DisplayMode { ImageMode =  1, ContourMode =  2 }
enum ItemAttribute { Legend =  1, AutoScale =  2 }
enum RenderHint { RenderAntialiased =  1 }
enum RttiValues { Rtti_PlotItem =  0, Rtti_PlotGrid, Rtti_PlotScale, Rtti_PlotMarker, Rtti_PlotCurve, Rtti_PlotHistogram, Rtti_PlotSpectrogram, Rtti_PlotSVG, Rtti_PlotUserItem =  1000 }

int alpha () const
void attach (QwtPlot *plot)
virtual QwtDoubleRect boundingRect () const
CachePolicy cachePolicy () const
const QwtColorMap & colorMap () const
QwtValueList contourLevels () const
virtual QPen contourPen (double level) const
const QwtRasterData & data () const
QPen defaultContourPen () const
void detach ()
virtual void draw (QPainter *p, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRect &rect) const
void hide ()
void invalidateCache ()
QwtDoubleRect invTransform (const QwtScaleMap &, const QwtScaleMap &, const QRect &) const
bool isVisible () const
virtual void itemChanged ()
virtual QWidget * legendItem () const
QRect paintRect (const QwtScaleMap &, const QwtScaleMap &) const
QwtPlot * plot () const
QwtPlotSpectrogram (const QString &title=QString::null)
virtual QSize rasterHint (const QwtDoubleRect &) const
virtual int rtti () const
QwtDoubleRect scaleRect (const QwtScaleMap &, const QwtScaleMap &) const
void setAlpha (int alpha)
void setAxis (int xAxis, int yAxis)
void setCachePolicy (CachePolicy)
void setColorMap (const QwtColorMap &)
void setConrecAttribute (QwtRasterData::ConrecAttribute, bool on)
void setContourLevels (const QwtValueList &)
void setData (const QwtRasterData &data)
void setDefaultContourPen (const QPen &)
void setDisplayMode (DisplayMode, bool on=true)
void setItemAttribute (ItemAttribute, bool on=true)
void setRenderHint (RenderHint, bool on=true)
void setTitle (const QwtText &title)
void setTitle (const QString &title)
virtual void setVisible (bool)
void setXAxis (int axis)
void setYAxis (int axis)
void setZ (double z)
void show ()
bool testConrecAttribute (QwtRasterData::ConrecAttribute) const
bool testDisplayMode (DisplayMode) const
bool testItemAttribute (ItemAttribute) const
bool testRenderHint (RenderHint) const
const QwtText & title () const
QRect transform (const QwtScaleMap &, const QwtScaleMap &, const QwtDoubleRect &) const
virtual void updateLegend (QwtLegend *) const
virtual void updateScaleDiv (const QwtScaleDiv &, const QwtScaleDiv &)
int xAxis () const
int yAxis () const
double z () const
virtual ~QwtPlotSpectrogram ()

virtual QSize contourRasterSize (const QwtDoubleRect &, const QRect &) const
virtual void drawContourLines (QPainter *p, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QwtRasterData::ContourLines &lines) const
virtual QwtRasterData::ContourLines renderContourLines (const QwtDoubleRect &rect, const QSize &raster) const
virtual QImage renderImage (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QwtDoubleRect &rect) const

NoCache
renderImage() is called, whenever the item has to be repainted

• PaintCache
  renderImage() is called, whenever the image cache is not valid, or the scales, or the size of the canvas has changed. This type of cache is only useful for improving the performance of hide/show operations. All other situations are already handled by the plot canvas cache.
• ScreenCache
  The screen cache is an image in size of the screen. As long as the scales don't change the target image is scaled from the cache. This might improve the performance when resizing the plot widget, but suffers from scaling effects.

The default policy is NoCache

• 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:

• Legend
  The item is represented on the legend.
• AutoScale
  The boundingRect() of the item is included in the autoscaling calculation.

See also:

Render hints.

Runtime type information. RttiValues is used to cast plot items, without having to enable runtime type information of the compiler.

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

The z value is initialized by 8.0.

Parameters:

title Title

See also:

QwtPlotItem::setItemAttribute(), QwtPlotItem::setZ()

Destructor.

See also:

Attach the item to a plot. This method will attach a QwtPlotItem to the QwtPlot argument. It will first detach the QwtPlotItem from any plot from a previous call to attach (if necessary). If a NULL argument is passed, it will detach from any QwtPlot it was attached to.

Parameters:

plot Plot widget

See also:

QwtPlotItem::detach()

See also:

Reimplemented from QwtPlotItem.

See also:

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

See also:

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()

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()

See also:

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This method detaches a QwtPlotItem from any QwtPlot it has been associated with. detach() is equivalent to calling attach( NULL )

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Draw the spectrogram. Parameters:

See also:

Reimplemented from QwtPlotRasterItem.

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()

Hide the item.

See also:

Parameters:

xMap X map
yMap Y map
rect Rectangle in paint coordinates

Returns:

Rectangle in scale coordinates

See also:

transform()

See also:

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Allocate the widget that represents the item on the legend. The default implementation is made for QwtPlotCurve and returns a QwtLegendItem(), but an item could be represented by any type of widget, by overloading legendItem() and updateLegend().

Returns:

QwtLegendItem()

See also:

updateLegend() QwtLegend()

Implements QwtLegendItemManager.

Calculate the bounding paint rect of 2 maps. Parameters:

Returns:

Bounding rect of the scale maps

Return attached plot.

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.

Parameters:

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

See also:

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

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.

Reimplemented from QwtPlotItem.

Calculate the bounding scale rect of 2 maps. Parameters:

Returns:

Bounding rect of the scale maps

Set an alpha value for the raster data. Often a plot has several types of raster data organized in layers. ( f.e a geographical map, with weather statistics ). Using setAlpha() raster items can be stacked easily.

The alpha value is a value [0, 255] to control the transparency of the image. 0 represents a fully transparent color, while 255 represents a fully opaque color.

Parameters:

alpha Alpha value

• alpha >= 0
  All alpha values of the pixels returned by renderImage() will be set to alpha, beside those with an alpha value of 0 (invalid pixels).
• alpha < 0 The alpha values returned by renderImage() are not changed.

The default alpha value is -1.

See also:

The item will painted according to the coordinates its Axes.

Parameters:

xAxis X Axis
yAxis Y Axis

See also:

setXAxis(), setYAxis(), xAxis(), yAxis()

The default policy is NoCache

Parameters:

policy Cache policy

See also:

CachePolicy, cachePolicy()

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()

Parameters:

attribute CONREC attribute
on On/Off

See also:

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

Parameters:

levels Values of the contour levels

See also:

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

Note:

contourLevels returns the same levels but sorted.

Parameters:

data Spectrogram Data

See also:

data()

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:

Parameters:

mode Display mode
on On/Off

The default setting enables ImageMode.

See also:

Parameters:

attribute Attribute type
on true/false

See also:

testItemAttribute(), ItemAttribute

Parameters:

hint Render hint
on true/false

See also:

testRenderHint(), RenderHint

Parameters:

title Title

See also:

title()

Parameters:

title Title

See also:

title()

Parameters:

on Show if true, otherwise hide

See also:

isVisible(), show(), hide()

The item will painted according to the coordinates its Axes.

Parameters:

axis X Axis

See also:

setAxis(), setYAxis(), xAxis()

The item will painted according to the coordinates its Axes.

Parameters:

axis Y Axis

See also:

setAxis(), setXAxis(), yAxis()

Set the z value. Plot items are painted in increasing z-order.

Parameters:

z Z-value

See also:

z(), QwtPlotDict::itemList()

Show the item.

Parameters:

attribute CONREC attribute

Returns:

true, is enabled

See also:

setConrecAttribute(), renderContourLines(), QwtRasterData::contourLines()

Parameters:

mode Display mode

Returns:

true if mode is enabled

Parameters:

attribute Attribute type

Returns:

true/false

See also:

setItemAttribute(), ItemAttribute

Parameters:

hint Render hint

Returns:

true/false

See also:

setRenderHint(), RenderHint

See also:

Parameters:

xMap X map
yMap Y map
rect Rectangle in scale coordinates

Returns:

Rectangle in paint coordinates

See also:

invTransform()

Update the widget that represents the item on the legend. updateLegend() is called from itemChanged() to adopt the widget representing the item on the legend to its new configuration.

The default implementation is made for QwtPlotCurve and updates a QwtLegendItem(), but an item could be represented by any type of widget, by overloading legendItem() and updateLegend().

Parameters:

legend Legend

See also:

legendItem(), itemChanged(), QwtLegend()

Implements QwtLegendItemManager.

Reimplemented in QwtPlotCurve.

Update the item to changes of the axes scale division. Update the item, when the axes of plot have changed. The default implementation does nothing, but items that depend on the scale division (like QwtPlotGrid()) have to reimplement updateScaleDiv()

Parameters:

xScaleDiv Scale division of the x-axis
yScaleDiv Scale division of the y-axis

See also:

QwtPlot::updateAxes()

Reimplemented in QwtPlotGrid, and QwtPlotScaleItem.

Return xAxis.

Return yAxis.

Returns:

setZ(), QwtPlotDict::itemList()