Qwt User's Guide 6.3.0
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QwtPolarGrid Class Reference

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

#include <qwt_polar_grid.h>

Inheritance diagram for QwtPolarGrid:

Public Types

enum  DisplayFlag {
  SmartOriginLabel = 1 , HideMaxRadiusLabel = 2 , ClipAxisBackground = 4 , SmartScaleDraw = 8 ,
  ClipGridLines = 16
}
 
enum  GridAttribute { AutoScaling = 0x01 }
 Grid attributes. More...
 
typedef QFlags< DisplayFlagDisplayFlags
 
typedef QFlags< GridAttributeGridAttributes
 
- Public Types inherited from QwtPolarItem
enum  RttiValues {
  Rtti_PolarItem = 0 , Rtti_PolarGrid , Rtti_PolarMarker , Rtti_PolarCurve ,
  Rtti_PolarSpectrogram , Rtti_PolarUserItem = 1000
}
 Runtime type information. More...
 
enum  ItemAttribute { Legend = 0x01 , AutoScale = 0x02 }
 Plot Item Attributes. More...
 
enum  RenderHint { RenderAntialiased = 0x01 }
 Render hints. More...
 
typedef QFlags< ItemAttributeItemAttributes
 
typedef QFlags< RenderHintRenderHints
 

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 QwtScaleDrawscaleDraw (int axisId) const
 
QwtScaleDrawscaleDraw (int axisId)
 
void setAzimuthScaleDraw (QwtRoundScaleDraw *)
 Set a scale draw for the azimuth scale.
 
const QwtRoundScaleDrawazimuthScaleDraw () const
 
QwtRoundScaleDrawazimuthScaleDraw ()
 
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
 
- Public Member Functions inherited from QwtPolarItem
 QwtPolarItem (const QwtText &title=QwtText())
 
virtual ~QwtPolarItem ()
 Destroy the QwtPolarItem.
 
void attach (QwtPolarPlot *plot)
 Attach the item to a plot.
 
void detach ()
 This method detaches a QwtPolarItem from the QwtPolarPlot it has been associated with.
 
QwtPolarPlotplot () const
 
void setTitle (const QString &title)
 
void setTitle (const QwtText &title)
 
const QwtTexttitle () const
 
void setItemAttribute (ItemAttribute, bool on=true)
 
bool testItemAttribute (ItemAttribute) const
 
void setRenderHint (RenderHint, bool on=true)
 
bool testRenderHint (RenderHint) const
 
void setRenderThreadCount (uint numThreads)
 
uint renderThreadCount () const
 
double z () const
 
void setZ (double z)
 Set the z value.
 
void show ()
 Show the item.
 
void hide ()
 Hide the item.
 
virtual void setVisible (bool)
 
bool isVisible () const
 
virtual void itemChanged ()
 
virtual void legendChanged ()
 
virtual QwtInterval boundingInterval (int scaleId) const
 
void setLegendIconSize (const QSize &)
 
QSize legendIconSize () const
 
virtual QList< QwtLegendDatalegendData () const
 Return all information, that is needed to represent the item on the legend.
 
virtual QwtGraphic legendIcon (int index, const QSizeF &) const
 

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

◆ DisplayFlags

An ORed combination of DisplayFlag values.

Definition at line 88 of file qwt_polar_grid.h.

◆ GridAttributes

An ORed combination of GridAttribute values.

Definition at line 103 of file qwt_polar_grid.h.

Member Enumeration Documentation

◆ 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.

◆ 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::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.

◆ ~QwtPolarGrid()

QwtPolarGrid::~QwtPolarGrid ( )
virtual

Destructor.

Definition at line 157 of file qwt_polar_grid.cpp.

Member Function Documentation

◆ axisFont()

QFont QwtPolarGrid::axisFont ( int axisId) const
Returns
Font for the tick labels of a specific axis
Parameters
axisIdAxis id (QwtPolar::Axis)

Definition at line 556 of file qwt_polar_grid.cpp.

◆ axisPen()

QPen QwtPolarGrid::axisPen ( int axisId) const
Returns
Pen for painting a specific axis
Parameters
axisIdAxis id (QwtPolar::Axis)
See also
setAxisPen()

Definition at line 525 of file qwt_polar_grid.cpp.

◆ azimuthScaleDraw() [1/2]

QwtRoundScaleDraw * QwtPolarGrid::azimuthScaleDraw ( )
Returns
Scale draw for the azimuth scale
See also
setAzimuthScaleDraw(), scaleDraw()

Definition at line 1127 of file qwt_polar_grid.cpp.

◆ azimuthScaleDraw() [2/2]

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.

◆ draw()

void QwtPolarGrid::draw ( QPainter * painter,
const QwtScaleMap & azimuthMap,
const QwtScaleMap & radialMap,
const QPointF & pole,
double radius,
const QRectF & canvasRect ) const
overridevirtual

Draw the grid and axes

Parameters
painterPainter
azimuthMapMaps azimuth values to values related to 0.0, M_2PI
radialMapMaps radius values into painter coordinates.
polePosition of the pole in painter coordinates
radiusRadius of the complete plot area in painter coordinates
canvasRectContents rect of the canvas in painter coordinates

Implements QwtPolarItem.

Definition at line 574 of file qwt_polar_grid.cpp.

◆ drawAxis()

void QwtPolarGrid::drawAxis ( QPainter * painter,
int axisId ) const
protected

Paint an axis

Parameters
painterPainter
axisIdAxis id (QwtPolar::Axis)

Definition at line 832 of file qwt_polar_grid.cpp.

◆ drawCircles()

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

Draw circles

Parameters
painterPainter
canvasRectContents rect of the canvas in painter coordinates
polePosition of the pole in painter coordinates
radialMapMaps radius values into painter coordinates.
valuesRadial values, indicating the distances from the pole

Definition at line 751 of file qwt_polar_grid.cpp.

◆ drawRays()

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
painterPainter
canvasRectContents rect of the canvas in painter coordinates
polePosition of the pole in painter coordinates
radiusLength of the lines in painter coordinates
azimuthMapMaps azimuth values to values related to 0.0, M_2PI
valuesAzimuth values, indicating the direction of the lines

Definition at line 681 of file qwt_polar_grid.cpp.

◆ isAxisVisible()

bool QwtPolarGrid::isAxisVisible ( int axisId) const
Returns
true if the axis is visible
Parameters
axisIdAxis id (QwtPolar::Axis)
See also
showAxis()

Definition at line 343 of file qwt_polar_grid.cpp.

◆ isGridVisible()

bool QwtPolarGrid::isGridVisible ( int scaleId) const
Returns
true if grid lines are enabled
Parameters
scaleIdScale id ( QwtPolar::Scale )
See also
QwtPolar::Scale, showGrid()

Definition at line 272 of file qwt_polar_grid.cpp.

◆ isMinorGridVisible()

bool QwtPolarGrid::isMinorGridVisible ( int scaleId) const
Returns
true if minor grid lines are enabled
Parameters
scaleIdScale id ( QwtPolar::Scale )
See also
showMinorGrid()

Definition at line 308 of file qwt_polar_grid.cpp.

◆ majorGridPen()

QPen QwtPolarGrid::majorGridPen ( int scaleId) const
Returns
Pen for painting the major grid lines of a specific scale
Parameters
scaleIdScale id ( QwtPolar::Scale )
See also
setMajorGridPen(), minorGridPen()

Definition at line 454 of file qwt_polar_grid.cpp.

◆ marginHint()

int QwtPolarGrid::marginHint ( ) const
overridevirtual
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.

◆ minorGridPen()

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

Definition at line 510 of file qwt_polar_grid.cpp.

◆ rtti()

int QwtPolarGrid::rtti ( ) const
overridevirtual
Returns
QwtPlotItem::Rtti_PolarGrid

Reimplemented from QwtPolarItem.

Definition at line 163 of file qwt_polar_grid.cpp.

◆ scaleDraw() [1/2]

QwtScaleDraw * QwtPolarGrid::scaleDraw ( int axisId)

Returns the scale draw of a specified axis

Parameters
axisIdaxis 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.

◆ scaleDraw() [2/2]

const QwtScaleDraw * QwtPolarGrid::scaleDraw ( int axisId) const

Returns the scale draw of a specified axis

Parameters
axisIdaxis 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.

◆ setAxisFont()

void QwtPolarGrid::setAxisFont ( int axisId,
const QFont & font )

Assign a font for the tick labels of a specific axis

Parameters
axisIdAxis id (QwtPolar::Axis)
fontnew Font

Definition at line 539 of file qwt_polar_grid.cpp.

◆ setAxisPen()

void QwtPolarGrid::setAxisPen ( int axisId,
const QPen & pen )

Assign a pen for painting an axis

Parameters
axisIdAxis id (QwtPolar::Axis)
penPen
See also
axisPen()

Definition at line 235 of file qwt_polar_grid.cpp.

◆ setAzimuthScaleDraw()

void QwtPolarGrid::setAzimuthScaleDraw ( QwtRoundScaleDraw * scaleDraw)

Set a scale draw for the azimuth scale.

Parameters
scaleDrawobject responsible for drawing scales.
See also
azimuthScaleDraw(), setScaleDraw()

Definition at line 1139 of file qwt_polar_grid.cpp.

◆ setDisplayFlag()

void QwtPolarGrid::setDisplayFlag ( DisplayFlag flag,
bool on = true )

Change the display flags

Parameters
flagSee DisplayFlag
ontrue/false

Definition at line 174 of file qwt_polar_grid.cpp.

◆ setFont()

void QwtPolarGrid::setFont ( const QFont & font)

Assign a font for all scale tick labels

Parameters
fontFont
See also
setAxisFont()

Definition at line 390 of file qwt_polar_grid.cpp.

◆ setGridAttribute()

void QwtPolarGrid::setGridAttribute ( GridAttribute attribute,
bool on = true )

Specify an attribute for the grid.

Parameters
attributeGrid attribute
onOn/Off

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

Definition at line 205 of file qwt_polar_grid.cpp.

◆ setMajorGridPen() [1/2]

void QwtPolarGrid::setMajorGridPen ( const QPen & pen)

Assign a pen for the major grid lines

Parameters
penPen
See also
setPen(), setMinorGridPen(), majorGridPen

Definition at line 412 of file qwt_polar_grid.cpp.

◆ setMajorGridPen() [2/2]

void QwtPolarGrid::setMajorGridPen ( int scaleId,
const QPen & pen )

Assign a pen for the major grid lines of a specific scale

Parameters
scaleIdScale id ( QwtPolar::Scale )
penPen
See also
setPen(), setMinorGridPen(), majorGridPen

Definition at line 436 of file qwt_polar_grid.cpp.

◆ setMinorGridPen() [1/2]

void QwtPolarGrid::setMinorGridPen ( const QPen & pen)

Assign a pen for the minor grid lines

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

Definition at line 469 of file qwt_polar_grid.cpp.

◆ setMinorGridPen() [2/2]

void QwtPolarGrid::setMinorGridPen ( int scaleId,
const QPen & pen )

Assign a pen for the minor grid lines of a specific scale

Parameters
scaleIdScale id ( QwtPolar::Scale )
penPen
See also
setPen(), setMajorGridPen(), minorGridPen

Definition at line 493 of file qwt_polar_grid.cpp.

◆ setPen()

void QwtPolarGrid::setPen ( const QPen & pen)

Assign a pen for all axes and grid lines

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

Definition at line 357 of file qwt_polar_grid.cpp.

◆ setScaleDraw()

void QwtPolarGrid::setScaleDraw ( int axisId,
QwtScaleDraw * scaleDraw )

Set a scale draw.

Parameters
axisIdaxis index ( QwtPolar::AxisLeft <= axisId <= QwtPolar::AxisBottom)
scaleDrawobject responsible for drawing scales.
See also
scaleDraw(), setAzimuthScaleDraw()

Definition at line 1099 of file qwt_polar_grid.cpp.

◆ showAxis()

void QwtPolarGrid::showAxis ( int axisId,
bool show = true )

Show/Hide an axis

Parameters
axisIdAxis id (QwtPolar::Axis)
showtrue/false
See also
isAxisVisible()

Definition at line 324 of file qwt_polar_grid.cpp.

◆ showGrid()

void QwtPolarGrid::showGrid ( int scaleId,
bool show = true )

Show/Hide grid lines for a scale

Parameters
scaleIdScale id ( QwtPolar::Scale )
showtrue/false

Definition at line 254 of file qwt_polar_grid.cpp.

◆ showMinorGrid()

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
scaleIdScale id ( QwtPolar::Scale )
showtrue/false
See also
showGrid

Definition at line 290 of file qwt_polar_grid.cpp.

◆ testDisplayFlag()

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

Definition at line 191 of file qwt_polar_grid.cpp.

◆ testGridAttribute()

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.

◆ updateScaleDiv()

void QwtPolarGrid::updateScaleDiv ( const QwtScaleDiv & azimuthScaleDiv,
const QwtScaleDiv & radialScaleDiv,
const QwtInterval & interval )
overridevirtual

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
azimuthScaleDivScale division of the azimuth-scale
radialScaleDivScale division of the radius-axis
intervalThe 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.