QwtPlotSpectrogram(3) Qwt User's Guide QwtPlotSpectrogram(3)
NAME
QwtPlotSpectrogram -
A plot item, which displays a spectrogram.
SYNOPSIS
#include <qwt_plot_spectrogram.h>
Inherits QwtPlotRasterItem.
Public Types
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 }
Public Member Functions
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 ()
Protected Member Functions
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
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 QwtPlotRasterItem::CachePolicy [inherited] .IP o 2
NoCache
renderImage() is called, whenever the item has to be repainted
o 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.
o 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
enum QwtPlotSpectrogram::DisplayMode The display mode controls how the raster data will be represented.
o ImageMode
The values are mapped to colors using a color map.
o 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()
enum QwtPlotItem::ItemAttribute [inherited] Plot Item Attributes
o Legend
The item is represented on the legend.
o AutoScale
The boundingRect() of the item is included in the autoscaling calculation.
See also:
setItemAttribute(), testItemAttribute()
enum QwtPlotItem::RenderHint [inherited]
Render hints.
enum QwtPlotItem::RttiValues [inherited]
Runtime type information. RttiValues is used to cast plot items, without having to enable runtime type information of the compiler.
Constructor &; Destructor Documentation
QwtPlotSpectrogram::QwtPlotSpectrogram (const QString &title = QString::null) [explicit] Sets the following item attributes:
o QwtPlotItem::AutoScale: true
o 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
int QwtPlotRasterItem::alpha () const [inherited] Returns:
Alpha value of the raster item
See also:
setAlpha()
void QwtPlotItem::attach (QwtPlot *plot) [inherited]
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()
QwtDoubleRect QwtPlotSpectrogram::boundingRect () const [virtual] Returns:
Bounding rect of the data
See also:
QwtRasterData::boundingRect()
Reimplemented from QwtPlotItem.
QwtPlotRasterItem::CachePolicy QwtPlotRasterItem::cachePolicy () const [inherited] Returns:
Cache policy
See also:
CachePolicy, setCachePolicy()
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 (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 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 QwtPlotItem::detach () [inline, inherited]
This method detaches a QwtPlotItem from any QwtPlot it has been associated with. detach() is equivalent to calling attach( NULL )
See also:
attach( QwtPlot* plot )
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()
void QwtPlotItem::hide () [inherited]
Hide the item.
void QwtPlotRasterItem::invalidateCache () [inherited] Invalidate the paint cache
See also:
setCachePolicy()
QwtDoubleRect QwtPlotItem::invTransform (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRect &rect) const [inherited] Transform a
rectangle from paint to scale coordinates
Parameters:
xMap X map
yMap Y map
rect Rectangle in paint coordinates
Returns:
Rectangle in scale coordinates
See also:
transform()
bool QwtPlotItem::isVisible () const [inherited] Returns:
true if visible
See also:
setVisible(), show(), hide()
void QwtPlotItem::itemChanged () [virtual, inherited] Update the legend and call QwtPlot::autoRefresh for the parent plot.
See also:
updateLegend()
QWidget * QwtPlotItem::legendItem () const [virtual, inherited]
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.
QRect QwtPlotItem::paintRect (const QwtScaleMap &xMap, const QwtScaleMap &yMap) const [inherited]
Calculate the bounding paint rect of 2 maps. Parameters:
xMap X map
yMap X map
Returns:
Bounding rect of the scale maps
QwtPlot * QwtPlotItem::plot () const [inherited]
Return attached plot.
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.
QwtDoubleRect QwtPlotItem::scaleRect (const QwtScaleMap &xMap, const QwtScaleMap &yMap) const [inherited]
Calculate the bounding scale rect of 2 maps. Parameters:
xMap X map
yMap X map
Returns:
Bounding rect of the scale maps
void QwtPlotRasterItem::setAlpha (intalpha) [inherited]
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
o 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).
o alpha < 0 The alpha values returned by renderImage() are not changed.
The default alpha value is -1.
See also:
alpha()
void QwtPlotItem::setAxis (intxAxis, intyAxis) [inherited] Set X and Y axis
The item will painted according to the coordinates its Axes.
Parameters:
xAxis X Axis
yAxis Y Axis
See also:
setXAxis(), setYAxis(), xAxis(), yAxis()
void QwtPlotRasterItem::setCachePolicy (QwtPlotRasterItem::CachePolicypolicy) [inherited] Change the cache policy
The default policy is NoCache
Parameters:
policy Cache policy
See also:
CachePolicy, cachePolicy()
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::ConrecAttributeattribute, boolon) 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 (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 QwtPlotItem::setItemAttribute (ItemAttributeattribute, boolon = true) [inherited] Toggle an item attribute
Parameters:
attribute Attribute type
on true/false
See also:
testItemAttribute(), ItemAttribute
void QwtPlotItem::setRenderHint (RenderHinthint, boolon = true) [inherited] Toggle an render hint
Parameters:
hint Render hint
on true/false
See also:
testRenderHint(), RenderHint
void QwtPlotItem::setTitle (const QwtText &title) [inherited] Set a new title
Parameters:
title Title
See also:
title()
void QwtPlotItem::setTitle (const QString &title) [inherited] Set a new title
Parameters:
title Title
See also:
title()
void QwtPlotItem::setVisible (boolon) [virtual, inherited] Show/Hide the item
Parameters:
on Show if true, otherwise hide
See also:
isVisible(), show(), hide()
void QwtPlotItem::setXAxis (intaxis) [inherited] Set the X axis
The item will painted according to the coordinates its Axes.
Parameters:
axis X Axis
See also:
setAxis(), setYAxis(), xAxis()
void QwtPlotItem::setYAxis (intaxis) [inherited] Set the Y axis
The item will painted according to the coordinates its Axes.
Parameters:
axis Y Axis
See also:
setAxis(), setXAxis(), yAxis()
void QwtPlotItem::setZ (doublez) [inherited]
Set the z value. Plot items are painted in increasing z-order.
Parameters:
z Z-value
See also:
z(), QwtPlotDict::itemList()
void QwtPlotItem::show () [inherited]
Show the item.
bool QwtPlotSpectrogram::testConrecAttribute (QwtRasterData::ConrecAttributeattribute) 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 (DisplayModemode) const The display mode controls how the raster data will be represented.
Parameters:
mode Display mode
Returns:
true if mode is enabled
bool QwtPlotItem::testItemAttribute (ItemAttributeattribute) const [inherited] Test an item attribute
Parameters:
attribute Attribute type
Returns:
true/false
See also:
setItemAttribute(), ItemAttribute
bool QwtPlotItem::testRenderHint (RenderHinthint) const [inherited] Test a render hint
Parameters:
hint Render hint
Returns:
true/false
See also:
setRenderHint(), RenderHint
const QwtText & QwtPlotItem::title () const [inherited] Returns:
Title of the item
See also:
setTitle()
QRect QwtPlotItem::transform (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QwtDoubleRect &rect) const [inherited] Transform a
rectangle
Parameters:
xMap X map
yMap Y map
rect Rectangle in scale coordinates
Returns:
Rectangle in paint coordinates
See also:
invTransform()
void QwtPlotItem::updateLegend (QwtLegend *legend) const [virtual, inherited]
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.
void QwtPlotItem::updateScaleDiv (const QwtScaleDiv &, const QwtScaleDiv &) [virtual, inherited]
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.
int QwtPlotItem::xAxis () const [inherited]
Return xAxis.
int QwtPlotItem::yAxis () const [inherited]
Return yAxis.
double QwtPlotItem::z () const [inherited] Plot items are painted in increasing z-order.
Returns:
setZ(), QwtPlotDict::itemList()
Author
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Version 5.2.2 Mon Aug 1 2011 QwtPlotSpectrogram(3)