QwtNullPaintDevice(3)          Qwt User's Guide          QwtNullPaintDevice(3)

NAME
       QwtNullPaintDevice - A null paint device doing nothing.


SYNOPSIS
       #include <qwt_null_paintdevice.h>

       Inherits QPaintDevice.

       Inherited by QwtGraphic.

   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 override
           See QPaintDevice::paintEngine()
       virtual int metric (PaintDeviceMetric) const override
       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.

       Definition at line 32 of file qwt_null_paintdevice.h.

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:

       o drawPath()

       o drawPixmap()

       o drawImage()

       o 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:

       o drawPath()

       o drawPixmap()

       o drawImage()

       Definition at line 40 of file qwt_null_paintdevice.h.

Member Function Documentation
   int QwtNullPaintDevice::metric (PaintDeviceMetric deviceMetric) const
       [override],  [virtual]
       See QPaintDevice::metric()

       Parameters
           deviceMetric Type of metric

       Returns
           Metric information for the given paint device metric.

       See also
           sizeMetrics()

       Definition at line 422 of file qwt_null_paintdevice.cpp.

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

       See also
           setMode()

       Definition at line 395 of file qwt_null_paintdevice.cpp.

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

       Parameters
           mode New mode

       See also
           mode()

       Definition at line 386 of file qwt_null_paintdevice.cpp.

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

       Implemented in QwtGraphic.


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

Version 6.2.0                   Sun Jul 18 2021          QwtNullPaintDevice(3)