Provided by: libqwt5-doc_5.2.2-1ubuntu2_all bug

NAME

       QwtPlotRasterItem -

       A class, which displays raster data.

SYNOPSIS

       #include <qwt_plot_rasteritem.h>

       Inherits QwtPlotItem.

       Inherited by QwtPlotSpectrogram.

   Public Types
       enum CachePolicy { NoCache, PaintCache, ScreenCache }
       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
       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
       QwtPlotRasterItem (const QString &title=QString::null)
       QwtPlotRasterItem (const QwtText &title)
       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 setItemAttribute (ItemAttribute, bool on=true)
       void setRenderHint (RenderHint, bool on=true)
       void setTitle (const QString &title)
       void setTitle (const QwtText &title)
       virtual void setVisible (bool)
       void setXAxis (int axis)
       void setYAxis (int axis)
       void setZ (double z)
       void show ()
       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 ~QwtPlotRasterItem ()

   Protected Member Functions
       virtual QImage renderImage (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const
           QwtDoubleRect &area) const =0

Detailed Description

       A class, which displays raster data.

       Raster data is a grid of pixel values, that can be represented as a QImage. It is used for
       many types of information like spectrograms, cartograms, geographical maps ...

       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.

       QwtPlotRasterItem is only implemented for images of the following formats:
       QImage::Format_Indexed8, QImage::Format_ARGB32.

       See also:
           QwtPlotSpectrogram

Member Enumeration Documentation

   enum QwtPlotRasterItem::CachePolicy .IP · 2
       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

   enum QwtPlotItem::ItemAttribute [inherited] Plot Item Attributes
       · Legend
          The item is represented on the legend.

       · 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

   QwtPlotRasterItem::QwtPlotRasterItem (const QString &title = QString::null) [explicit]
       Constructor.

   QwtPlotRasterItem::QwtPlotRasterItem (const QwtText &title) [explicit]
       Constructor.

   QwtPlotRasterItem::~QwtPlotRasterItem () [virtual]
       Destructor.

Member Function Documentation

   int QwtPlotRasterItem::alpha () const 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 QwtPlotItem::boundingRect () const [virtual, inherited] Returns:
           An invalid bounding rect: QwtDoubleRect(1.0, 1.0, -2.0, -2.0)

       Reimplemented in QwtPlotCurve, QwtPlotMarker, QwtPlotSpectrogram, and QwtPlotSvgItem.

   QwtPlotRasterItem::CachePolicy QwtPlotRasterItem::cachePolicy () const Returns:
           Cache policy

       See also:
           CachePolicy, setCachePolicy()

   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 QwtPlotRasterItem::draw (QPainter *painter, const QwtScaleMap &xMap, const QwtScaleMap
       &yMap, const QRect &canvasRect) const [virtual]
       Draw the raster data. Parameters:
           painter Painter
           xMap X-Scale Map
           yMap Y-Scale Map
           canvasRect Contents rect of the plot canvas

       Implements QwtPlotItem.

       Reimplemented in QwtPlotSpectrogram.

   void QwtPlotItem::hide () [inherited]
       Hide the item.

   void QwtPlotRasterItem::invalidateCache () 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 QwtPlotRasterItem::rasterHint (const QwtDoubleRect &) const [virtual]
       Returns the recommended raster for a given rect. F.e the raster hint can be used to limit
       the resolution of the image that is rendered.

       The default implementation returns an invalid size (QSize()), what means: no hint.

       Reimplemented in QwtPlotSpectrogram.

   virtual QImage QwtPlotRasterItem::renderImage (const QwtScaleMap &xMap, const QwtScaleMap
       &yMap, const QwtDoubleRect &area) const [protected, pure virtual] Renders an image for an
       area
       The format of the image must be QImage::Format_Indexed8, QImage::Format_RGB32 or
       QImage::Format_ARGB32

       Parameters:
           xMap Maps x-values into pixel coordinates.
           yMap Maps y-values into pixel coordinates.
           area Requested area for the image in scale coordinates

       Implemented in QwtPlotSpectrogram.

   int QwtPlotItem::rtti () const [virtual, inherited] Return rtti for the specific class
       represented. QwtPlotItem is simply a virtual interface class, and base classes will
       implement this method with specific rtti values so a user can differentiate them.
       The rtti value is useful for environments, where the runtime type information is disabled
       and it is not possible to do a dynamic_cast<...>.

       Returns:
           rtti value

       See also:
           RttiValues

       Reimplemented in QwtPlotCurve, QwtPlotGrid, QwtPlotMarker, QwtPlotScaleItem,
       QwtPlotSpectrogram, and QwtPlotSvgItem.

   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)
       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:
           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) Change the cache
       policy
       The default policy is NoCache

       Parameters:
           policy Cache policy

       See also:
           CachePolicy, cachePolicy()

   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 QString &title) [inherited] Set a new title
       Parameters:
           title Title

       See also:
           title()

   void QwtPlotItem::setTitle (const QwtText &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 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

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