NAME

       QwtNullPaintDevice - A null paint device doing nothing.

SYNOPSIS

       #include <qwt_null_paintdevice.h>

       Inherits QPaintDevice.

       Inherited by QwtGraphic, and QwtStyleSheetRecorder.

   Public Types
       enum Mode { NormalMode, PolygonPathMode, PathMode }
           Render mode.

   Public Member Functions
       QwtNullPaintDevice ()
           Constructor.
       virtual ~QwtNullPaintDevice ()
           Destructor.
       void setMode (Mode)
       Mode mode () const
       virtual QPaintEngine * paintEngine () const
           See QPaintDevice::paintEngine()
       virtual int metric (PaintDeviceMetric) const
       virtual void drawRects (const QRect *, int)
           See QPaintEngine::drawRects()
       virtual void drawRects (const QRectF *, int)
           See QPaintEngine::drawRects()
       virtual void drawLines (const QLine *, int)
           See QPaintEngine::drawLines()
       virtual void drawLines (const QLineF *, int)
           See QPaintEngine::drawLines()
       virtual void drawEllipse (const QRectF &)
           See QPaintEngine::drawEllipse()
       virtual void drawEllipse (const QRect &)
           See QPaintEngine::drawEllipse()
       virtual void drawPath (const QPainterPath &)
           See QPaintEngine::drawPath()
       virtual void drawPoints (const QPointF *, int)
           See QPaintEngine::drawPoints()
       virtual void drawPoints (const QPoint *, int)
           See QPaintEngine::drawPoints()
       virtual void drawPolygon (const QPointF *, int, QPaintEngine::PolygonDrawMode)
           See QPaintEngine::drawPolygon()
       virtual void drawPolygon (const QPoint *, int, QPaintEngine::PolygonDrawMode)
           See QPaintEngine::drawPolygon()
       virtual void drawPixmap (const QRectF &, const QPixmap &, const QRectF &)
           See QPaintEngine::drawPixmap()
       virtual void drawTextItem (const QPointF &, const QTextItem &)
           See QPaintEngine::drawTextItem()
       virtual void drawTiledPixmap (const QRectF &, const QPixmap &, const QPointF &)
           See QPaintEngine::drawTiledPixmap()
       virtual void drawImage (const QRectF &, const QImage &, const QRectF &,
           Qt::ImageConversionFlags)
           See QPaintEngine::drawImage()
       virtual void updateState (const QPaintEngineState &)
           See QPaintEngine::updateState()

   Protected Member Functions
       virtual QSize sizeMetrics () const =0

Detailed Description

       A null paint device doing nothing.

       Sometimes important layout/rendering geometries are not available or changeable from the
       public Qt class interface. ( f.e hidden in the style implementation ).

       QwtNullPaintDevice can be used to manipulate or filter out this information by analyzing
       the stream of paint primitives.

       F.e. QwtNullPaintDevice is used by QwtPlotCanvas to identify styled backgrounds with
       rounded corners.

Member Enumeration Documentation

   enum QwtNullPaintDevice::Mode
       Render mode.

       See also:
           setMode(), mode()

       Enumerator

       NormalMode
              All vector graphic primitives are painted by the corresponding draw methods

       PolygonPathMode
              Vector graphic primitives ( beside polygons ) are mapped to a QPainterPath and are
              painted by drawPath. In PathMode mode only a few draw methods are called:

       • drawPath()

       • drawPixmap()

       • drawImage()

       • drawPolygon()

       PathMode
              Vector graphic primitives are mapped to a QPainterPath and are painted by drawPath.
              In PathMode mode only a few draw methods are called:

       • drawPath()

       • drawPixmap()

       • drawImage()

Member Function Documentation

   int QwtNullPaintDevice::metric (PaintDeviceMetric deviceMetric) const [virtual]
       See QPaintDevice::metric()

       Parameters:
           deviceMetric Type of metric

       Returns:
           Metric information for the given paint device metric.

       See also:
           sizeMetrics()

   QwtNullPaintDevice::Mode QwtNullPaintDevice::mode () const
       Returns:
           Render mode

       See also:
           setMode()

   void QwtNullPaintDevice::setMode (Mode mode)
       Set the render mode

       Parameters:
           mode New mode

       See also:
           mode()

   virtual QSize QwtNullPaintDevice::sizeMetrics () const [protected],  [pure virtual]
       Returns:
           Size needed to implement metric()

       Implemented in QwtGraphic.

Author

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