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

NAME
       QwtPolarGrid - An item which draws scales and grid lines on a polar
       plot.


SYNOPSIS
       #include <qwt_polar_grid.h>

       Inherits QwtPolarItem.

   Public Types
       enum DisplayFlag { SmartOriginLabel = 1, HideMaxRadiusLabel = 2,
           ClipAxisBackground = 4, SmartScaleDraw = 8, ClipGridLines = 16 }
       enum GridAttribute { AutoScaling = 0x01 }
           Grid attributes.
       typedef QFlags< DisplayFlag > DisplayFlags
       typedef QFlags< GridAttribute > GridAttributes

   Public Member Functions
       QwtPolarGrid ()
           Constructor.
       virtual ~QwtPolarGrid ()
           Destructor.
       virtual int rtti () const override
       void setDisplayFlag (DisplayFlag, bool on=true)
       bool testDisplayFlag (DisplayFlag) const
       void setGridAttribute (GridAttribute, bool on=true)
           Specify an attribute for the grid.
       bool testGridAttribute (GridAttribute) const
       void showGrid (int scaleId, bool show=true)
       bool isGridVisible (int scaleId) const
       void showMinorGrid (int scaleId, bool show=true)
       bool isMinorGridVisible (int scaleId) const
       void showAxis (int axisId, bool show=true)
       bool isAxisVisible (int axisId) const
       void setPen (const QPen &p)
       void setFont (const QFont &)
       void setMajorGridPen (const QPen &p)
       void setMajorGridPen (int scaleId, const QPen &p)
       QPen majorGridPen (int scaleId) const
       void setMinorGridPen (const QPen &p)
       void setMinorGridPen (int scaleId, const QPen &p)
       QPen minorGridPen (int scaleId) const
       void setAxisPen (int axisId, const QPen &p)
       QPen axisPen (int axisId) const
       void setAxisFont (int axisId, const QFont &p)
       QFont axisFont (int axisId) const
       void setScaleDraw (int axisId, QwtScaleDraw *)
           Set a scale draw.
       const QwtScaleDraw * scaleDraw (int axisId) const
       QwtScaleDraw * scaleDraw (int axisId)
       void setAzimuthScaleDraw (QwtRoundScaleDraw *)
           Set a scale draw for the azimuth scale.
       const QwtRoundScaleDraw * azimuthScaleDraw () const
       QwtRoundScaleDraw * azimuthScaleDraw ()
       virtual void draw (QPainter *p, const QwtScaleMap &azimuthMap, const
           QwtScaleMap &radialMap, const QPointF &pole, double radius, const
           QRectF &rect) const override
       virtual void updateScaleDiv (const QwtScaleDiv &azimuthMap, const
           QwtScaleDiv &radialMap, const QwtInterval &) override
           Update the item to changes of the axes scale division.
       virtual int marginHint () const override

   Protected Member Functions
       void drawRays (QPainter *, const QRectF &, const QPointF &pole, double
           radius, const QwtScaleMap &azimuthMap, const QList< double > &)
           const
       void drawCircles (QPainter *, const QRectF &, const QPointF &pole,
           const QwtScaleMap &radialMap, const QList< double > &) const
       void drawAxis (QPainter *, int axisId) const

Detailed Description
       An item which draws scales and grid lines on a polar plot.

       The QwtPolarGrid class can be used to draw a coordinate grid. A
       coordinate grid consists of major and minor gridlines. The locations of
       the gridlines are determined by the azimuth and radial scale divisions.

       QwtPolarGrid is also responsible for drawing the axis representing the
       scales. It is possible to display 4 radial and one azimuth axis.

       Whenever the scale divisions of the plot widget changes the grid is
       synchronized by updateScaleDiv().

       See also
           QwtPolarPlot, QwtPolar::Axis

       Definition at line 41 of file qwt_polar_grid.h.

Member Typedef Documentation
   typedef QFlags<DisplayFlag > QwtPolarGrid::DisplayFlags
       An ORed combination of DisplayFlag values.

       Definition at line 88 of file qwt_polar_grid.h.

   typedef QFlags<GridAttribute > QwtPolarGrid::GridAttributes
       An ORed combination of GridAttribute values.

       Definition at line 103 of file qwt_polar_grid.h.

Member Enumeration Documentation
   enum QwtPolarGrid::DisplayFlag
       Mysterious flags trying to avoid conflicts, when painting the scales
       and grid lines.

       The default setting enables all flags.

       See also
           setDisplayFlag(), testDisplayFlag()

       Enumerator

       SmartOriginLabel
              Try to avoid situations, where the label of the origin is
              painted over another axis.

       HideMaxRadiusLabel
              Often the outermost tick of the radial scale is close to the
              canvas border. With HideMaxRadiusLabel enabled it is not
              painted.

       ClipAxisBackground
              The tick labels of the radial scales might be hard to read, when
              they are painted on top of the radial grid lines ( or on top of
              a curve/spectrogram ). When ClipAxisBackground the bounding rect
              of each label is added to the clip region.

       SmartScaleDraw
              Don't paint the backbone of the radial axes, when they are very
              close to a line of the azimuth grid.

       ClipGridLines
              All grid lines are clipped against the plot area before being
              painted. When the plot is zoomed in this will have an
              significant impact on the performance of the painting code.

       Definition at line 52 of file qwt_polar_grid.h.

   enum QwtPolarGrid::GridAttribute
       Grid attributes.

       See also
           setGridAttributes(), testGridAttributes()

       Enumerator

       AutoScaling
              When AutoScaling is enabled, the radial axes will be adjusted to
              the interval, that is currently visible on the canvas plot.

       Definition at line 94 of file qwt_polar_grid.h.

Constructor & Destructor Documentation
   QwtPolarGrid::QwtPolarGrid () [explicit]
       Constructor. Enables major and disables minor grid lines. The azimuth
       and right radial axis are visible. all other axes are hidden.
       Autoscaling is enabled.

       Definition at line 84 of file qwt_polar_grid.cpp.

Member Function Documentation
   QFont QwtPolarGrid::axisFont (int axisId) const
       Returns
           Font for the tick labels of a specific axis

       Parameters
           axisId Axis id (QwtPolar::Axis)

       Definition at line 556 of file qwt_polar_grid.cpp.

   QPen QwtPolarGrid::axisPen (int axisId) const
       Returns
           Pen for painting a specific axis

       Parameters
           axisId Axis id (QwtPolar::Axis)

       See also
           setAxisPen()

       Definition at line 525 of file qwt_polar_grid.cpp.

   QwtRoundScaleDraw * QwtPolarGrid::azimuthScaleDraw ()
       Returns
           Scale draw for the azimuth scale

       See also
           setAzimuthScaleDraw(), scaleDraw()

       Definition at line 1127 of file qwt_polar_grid.cpp.

   const QwtRoundScaleDraw * QwtPolarGrid::azimuthScaleDraw () const
       Returns
           Scale draw for the azimuth scale

       See also
           setAzimuthScaleDraw(), scaleDraw()

       Definition at line 1117 of file qwt_polar_grid.cpp.

   void QwtPolarGrid::draw (QPainter * painter, const QwtScaleMap &
       azimuthMap, const QwtScaleMap & radialMap, const QPointF & pole, double
       radius, const QRectF & canvasRect) const [override],  [virtual]
       Draw the grid and axes

       Parameters
           painter Painter
           azimuthMap Maps azimuth values to values related to 0.0, M_2PI
           radialMap Maps radius values into painter coordinates.
           pole Position of the pole in painter coordinates
           radius Radius of the complete plot area in painter coordinates
           canvasRect Contents rect of the canvas in painter coordinates

       Implements QwtPolarItem.

       Definition at line 574 of file qwt_polar_grid.cpp.

   void QwtPolarGrid::drawAxis (QPainter * painter, int axisId) const
       [protected]
       Paint an axis

       Parameters
           painter Painter
           axisId Axis id (QwtPolar::Axis)

       Definition at line 832 of file qwt_polar_grid.cpp.

   void QwtPolarGrid::drawCircles (QPainter * painter, const QRectF &
       canvasRect, const QPointF & pole, const QwtScaleMap & radialMap, const
       QList< double > & values) const [protected]
       Draw circles

       Parameters
           painter Painter
           canvasRect Contents rect of the canvas in painter coordinates
           pole Position of the pole in painter coordinates
           radialMap Maps radius values into painter coordinates.
           values Radial values, indicating the distances from the pole

       Definition at line 751 of file qwt_polar_grid.cpp.

   void QwtPolarGrid::drawRays (QPainter * painter, const QRectF & canvasRect,
       const QPointF & pole, double radius, const QwtScaleMap & azimuthMap,
       const QList< double > & values) const [protected]
       Draw lines from the pole

       Parameters
           painter Painter
           canvasRect Contents rect of the canvas in painter coordinates
           pole Position of the pole in painter coordinates
           radius Length of the lines in painter coordinates
           azimuthMap Maps azimuth values to values related to 0.0, M_2PI
           values Azimuth values, indicating the direction of the lines

       Definition at line 681 of file qwt_polar_grid.cpp.

   bool QwtPolarGrid::isAxisVisible (int axisId) const
       Returns
           true if the axis is visible

       Parameters
           axisId Axis id (QwtPolar::Axis)

       See also
           showAxis()

       Definition at line 343 of file qwt_polar_grid.cpp.

   bool QwtPolarGrid::isGridVisible (int scaleId) const
       Returns
           true if grid lines are enabled

       Parameters
           scaleId Scale id ( QwtPolar::Scale )

       See also
           QwtPolar::Scale, showGrid()

       Definition at line 272 of file qwt_polar_grid.cpp.

   bool QwtPolarGrid::isMinorGridVisible (int scaleId) const
       Returns
           true if minor grid lines are enabled

       Parameters
           scaleId Scale id ( QwtPolar::Scale )

       See also
           showMinorGrid()

       Definition at line 308 of file qwt_polar_grid.cpp.

   QPen QwtPolarGrid::majorGridPen (int scaleId) const
       Returns
           Pen for painting the major grid lines of a specific scale

       Parameters
           scaleId Scale id ( QwtPolar::Scale )

       See also
           setMajorGridPen(), minorGridPen()

       Definition at line 454 of file qwt_polar_grid.cpp.

   int QwtPolarGrid::marginHint () const [override],  [virtual]
       Returns
           Number of pixels, that are necessary to paint the azimuth scale

       See also
           QwtRoundScaleDraw::extent()

       Reimplemented from QwtPolarItem.

       Definition at line 1049 of file qwt_polar_grid.cpp.

   QPen QwtPolarGrid::minorGridPen (int scaleId) const
       Returns
           Pen for painting the minor grid lines of a specific scale

       Parameters
           scaleId Scale id ( QwtPolar::Scale )

       Definition at line 510 of file qwt_polar_grid.cpp.

   int QwtPolarGrid::rtti () const [override],  [virtual]
       Returns
           QwtPlotItem::Rtti_PolarGrid

       Reimplemented from QwtPolarItem.

       Definition at line 163 of file qwt_polar_grid.cpp.

   QwtScaleDraw * QwtPolarGrid::scaleDraw (int axisId)
       Returns the scale draw of a specified axis

       Parameters
           axisId axis index ( QwtPolar::AxisLeft <= axisId <=
           QwtPolar::AxisBottom)

       Returns
           specified scaleDraw for axis, or NULL if axis is invalid.

       See also
           setScaleDraw(), azimuthScaleDraw()

       Definition at line 1083 of file qwt_polar_grid.cpp.

   const QwtScaleDraw * QwtPolarGrid::scaleDraw (int axisId) const
       Returns the scale draw of a specified axis

       Parameters
           axisId axis index ( QwtPolar::AxisLeft <= axisId <=
           QwtPolar::AxisBottom)

       Returns
           specified scaleDraw for axis, or NULL if axis is invalid.

       See also
           azimuthScaleDraw()

       Definition at line 1068 of file qwt_polar_grid.cpp.

   void QwtPolarGrid::setAxisFont (int axisId, const QFont & font)
       Assign a font for the tick labels of a specific axis

       Parameters
           axisId Axis id (QwtPolar::Axis)
           font new Font

       Definition at line 539 of file qwt_polar_grid.cpp.

   void QwtPolarGrid::setAxisPen (int axisId, const QPen & pen)
       Assign a pen for painting an axis

       Parameters
           axisId Axis id (QwtPolar::Axis)
           pen Pen

       See also
           axisPen()

       Definition at line 235 of file qwt_polar_grid.cpp.

   void QwtPolarGrid::setAzimuthScaleDraw (QwtRoundScaleDraw * scaleDraw)
       Set a scale draw for the azimuth scale.

       Parameters
           scaleDraw object responsible for drawing scales.

       See also
           azimuthScaleDraw(), setScaleDraw()

       Definition at line 1139 of file qwt_polar_grid.cpp.

   void QwtPolarGrid::setDisplayFlag (DisplayFlag flag, bool on = true)
       Change the display flags

       Parameters
           flag See DisplayFlag
           on true/false

       Definition at line 174 of file qwt_polar_grid.cpp.

   void QwtPolarGrid::setFont (const QFont & font)
       Assign a font for all scale tick labels

       Parameters
           font Font

       See also
           setAxisFont()

       Definition at line 390 of file qwt_polar_grid.cpp.

   void QwtPolarGrid::setGridAttribute (GridAttribute attribute, bool on =
       true)
       Specify an attribute for the grid.

       Parameters
           attribute Grid attribute
           on On/Off

       /sa GridAttribute, testGridAttribute(), updateScaleDiv(),
       QwtPolarPlot::zoom(), QwtPolarPlot::scaleDiv()

       Definition at line 205 of file qwt_polar_grid.cpp.

   void QwtPolarGrid::setMajorGridPen (const QPen & pen)
       Assign a pen for the major grid lines

       Parameters
           pen Pen

       See also
           setPen(), setMinorGridPen(), majorGridPen

       Definition at line 412 of file qwt_polar_grid.cpp.

   void QwtPolarGrid::setMajorGridPen (int scaleId, const QPen & pen)
       Assign a pen for the major grid lines of a specific scale

       Parameters
           scaleId Scale id ( QwtPolar::Scale )
           pen Pen

       See also
           setPen(), setMinorGridPen(), majorGridPen

       Definition at line 436 of file qwt_polar_grid.cpp.

   void QwtPolarGrid::setMinorGridPen (const QPen & pen)
       Assign a pen for the minor grid lines

       Parameters
           pen Pen

       See also
           setPen(), setMajorGridPen(), minorGridPen()

       Definition at line 469 of file qwt_polar_grid.cpp.

   void QwtPolarGrid::setMinorGridPen (int scaleId, const QPen & pen)
       Assign a pen for the minor grid lines of a specific scale

       Parameters
           scaleId Scale id ( QwtPolar::Scale )
           pen Pen

       See also
           setPen(), setMajorGridPen(), minorGridPen

       Definition at line 493 of file qwt_polar_grid.cpp.

   void QwtPolarGrid::setPen (const QPen & pen)
       Assign a pen for all axes and grid lines

       Parameters
           pen Pen

       See also
           setMajorGridPen(), setMinorGridPen(), setAxisPen()

       Definition at line 357 of file qwt_polar_grid.cpp.

   void QwtPolarGrid::setScaleDraw (int axisId, QwtScaleDraw * scaleDraw)
       Set a scale draw.

       Parameters
           axisId axis index ( QwtPolar::AxisLeft <= axisId <=
           QwtPolar::AxisBottom)
           scaleDraw object responsible for drawing scales.

       See also
           scaleDraw(), setAzimuthScaleDraw()

       Definition at line 1099 of file qwt_polar_grid.cpp.

   void QwtPolarGrid::showAxis (int axisId, bool show = true)
       Show/Hide an axis

       Parameters
           axisId Axis id (QwtPolar::Axis)
           show true/false

       See also
           isAxisVisible()

       Definition at line 324 of file qwt_polar_grid.cpp.

   void QwtPolarGrid::showGrid (int scaleId, bool show = true)
       Show/Hide grid lines for a scale

       Parameters
           scaleId Scale id ( QwtPolar::Scale )
           show true/false

       Definition at line 254 of file qwt_polar_grid.cpp.

   void QwtPolarGrid::showMinorGrid (int scaleId, bool show = true)
       Show/Hide minor grid lines for a scale

       To display minor grid lines. showGrid() needs to be enabled too.

       Parameters
           scaleId Scale id ( QwtPolar::Scale )
           show true/false

       See also
           showGrid

       Definition at line 290 of file qwt_polar_grid.cpp.

   bool QwtPolarGrid::testDisplayFlag (DisplayFlag flag) const
       Returns
           true, if flag is enabled

       Parameters
           flag See DisplayFlag

       Definition at line 191 of file qwt_polar_grid.cpp.

   bool QwtPolarGrid::testGridAttribute (GridAttribute attribute) const
       Returns
           true, if attribute is enabled

       See also
           GridAttribute, setGridAttribute()

       Definition at line 222 of file qwt_polar_grid.cpp.

   void QwtPolarGrid::updateScaleDiv (const QwtScaleDiv & azimuthScaleDiv,
       const QwtScaleDiv & radialScaleDiv, const QwtInterval & interval)
       [override],  [virtual]
       Update the item to changes of the axes scale division. If AutoScaling
       is enabled the radial scale is calculated from the interval, otherwise
       the scales are adopted to the plot scales.

       Parameters
           azimuthScaleDiv Scale division of the azimuth-scale
           radialScaleDiv Scale division of the radius-axis
           interval The interval of the radius-axis, that is visible on the
           canvas

       See also
           QwtPolarPlot::setGridAttributes()

       Reimplemented from QwtPolarItem.

       Definition at line 952 of file qwt_polar_grid.cpp.


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Version 6.2.0                   Sun Jul 18 2021                QwtPolarGrid(3)