Qwt User's Guide  6.1.3
QwtPlotScaleItem Class Reference

A class which draws a scale inside the plot canvas. More...

#include <qwt_plot_scaleitem.h>

Inheritance diagram for QwtPlotScaleItem:

Public Member Functions

 QwtPlotScaleItem (QwtScaleDraw::Alignment=QwtScaleDraw::BottomScale, const double pos=0.0)
 Constructor for scale item at the position pos. More...
virtual ~QwtPlotScaleItem ()
virtual int rtti () const
void setScaleDiv (const QwtScaleDiv &)
 Assign a scale division. More...
const QwtScaleDivscaleDiv () const
void setScaleDivFromAxis (bool on)
bool isScaleDivFromAxis () const
void setPalette (const QPalette &)
QPalette palette () const
void setFont (const QFont &)
QFont font () const
void setScaleDraw (QwtScaleDraw *)
 Set a scale draw. More...
const QwtScaleDrawscaleDraw () const
QwtScaleDrawscaleDraw ()
void setPosition (double pos)
double position () const
void setBorderDistance (int numPixels)
 Align the scale to the canvas. More...
int borderDistance () const
void setAlignment (QwtScaleDraw::Alignment)
virtual void draw (QPainter *p, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &rect) const
 Draw the scale.
virtual void updateScaleDiv (const QwtScaleDiv &, const QwtScaleDiv &)
 Update the item to changes of the axes scale division. More...
- Public Member Functions inherited from QwtPlotItem
 QwtPlotItem (const QwtText &title=QwtText())
virtual ~QwtPlotItem ()
 Destroy the QwtPlotItem.
void attach (QwtPlot *plot)
 Attach the item to a plot. More...
void detach ()
 This method detaches a QwtPlotItem from any QwtPlot it has been associated with. More...
QwtPlotplot () const
 Return attached plot.
void setTitle (const QString &title)
void setTitle (const QwtText &title)
const QwtTexttitle () const
void setItemAttribute (ItemAttribute, bool on=true)
bool testItemAttribute (ItemAttribute) const
void setItemInterest (ItemInterest, bool on=true)
bool testItemInterest (ItemInterest) const
void setRenderHint (RenderHint, bool on=true)
bool testRenderHint (RenderHint) const
void setRenderThreadCount (uint numThreads)
uint renderThreadCount () const
void setLegendIconSize (const QSize &)
QSize legendIconSize () const
double z () const
void setZ (double z)
 Set the z value. More...
void show ()
 Show the item.
void hide ()
 Hide the item.
virtual void setVisible (bool)
bool isVisible () const
void setAxes (int xAxis, int yAxis)
void setXAxis (int axis)
int xAxis () const
 Return xAxis.
void setYAxis (int axis)
int yAxis () const
 Return yAxis.
virtual void itemChanged ()
virtual void legendChanged ()
virtual QRectF boundingRect () const
virtual void getCanvasMarginHint (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasSize, double &left, double &top, double &right, double &bottom) const
 Calculate a hint for the canvas margin. More...
virtual void updateLegend (const QwtPlotItem *, const QList< QwtLegendData > &)
 Update the item to changes of the legend info. More...
QRectF scaleRect (const QwtScaleMap &, const QwtScaleMap &) const
 Calculate the bounding scale rectangle of 2 maps. More...
QRectF paintRect (const QwtScaleMap &, const QwtScaleMap &) const
 Calculate the bounding paint rectangle of 2 maps. More...
virtual QList< QwtLegendDatalegendData () const
 Return all information, that is needed to represent the item on the legend. More...
virtual QwtGraphic legendIcon (int index, const QSizeF &) const

Additional Inherited Members

- Public Types inherited from QwtPlotItem
enum  RttiValues {
  Rtti_PlotItem = 0, Rtti_PlotGrid, Rtti_PlotScale, Rtti_PlotLegend,
  Rtti_PlotMarker, Rtti_PlotCurve, Rtti_PlotSpectroCurve, Rtti_PlotIntervalCurve,
  Rtti_PlotHistogram, Rtti_PlotSpectrogram, Rtti_PlotSVG, Rtti_PlotTradingCurve,
  Rtti_PlotBarChart, Rtti_PlotMultiBarChart, Rtti_PlotShape, Rtti_PlotTextLabel,
  Rtti_PlotZone, Rtti_PlotUserItem = 1000
 Runtime type information. More...
enum  ItemAttribute { Legend = 0x01, AutoScale = 0x02, Margins = 0x04 }
 Plot Item Attributes. More...
enum  ItemInterest { ScaleInterest = 0x01, LegendInterest = 0x02 }
 Plot Item Interests. More...
enum  RenderHint { RenderAntialiased = 0x1 }
 Render hints. More...
typedef QFlags< ItemAttributeItemAttributes
 Plot Item Attributes.
typedef QFlags< ItemInterestItemInterests
 Plot Item Interests.
typedef QFlags< RenderHintRenderHints
 Render hints.
- Protected Member Functions inherited from QwtPlotItem
QwtGraphic defaultIcon (const QBrush &, const QSizeF &) const
 Return a default icon from a brush. More...

Detailed Description

A class which draws a scale inside the plot canvas.

QwtPlotScaleItem can be used to draw an axis inside the plot canvas. It might by synchronized to one of the axis of the plot, but can also display its own ticks and labels.

It is allowed to synchronize the scale item with a disabled axis. In plots with vertical and horizontal scale items, it might be necessary to remove ticks at the intersections, by overloading updateScaleDiv().

The scale might be at a specific position (f.e 0.0) or it might be aligned to a canvas border.

The following example shows how to replace the left axis, by a scale item at the x position 0.0.
QwtPlotScaleItem *scaleItem =
    new QwtPlotScaleItem(QwtScaleDraw::RightScale, 0.0);

plot->enableAxis(QwtPlot::yLeft, false);

Constructor & Destructor Documentation

QwtPlotScaleItem::QwtPlotScaleItem ( QwtScaleDraw::Alignment  alignment = QwtScaleDraw::BottomScale,
const double  pos = 0.0 

Constructor for scale item at the position pos.

alignmentIn case of QwtScaleDraw::BottomScale or QwtScaleDraw::TopScale the scale item is corresponding to the xAxis(), otherwise it corresponds to the yAxis().
posx or y position, depending on the corresponding axis.
See also
setPosition(), setAlignment()

Member Function Documentation

int QwtPlotScaleItem::borderDistance ( ) const
Distance from a canvas border
See also
setBorderDistance(), setPosition()
QFont QwtPlotScaleItem::font ( ) const
tick label font
See also
bool QwtPlotScaleItem::isScaleDivFromAxis ( ) const
True, if the synchronization of the scale division with the corresponding axis is enabled.
See also
setScaleDiv(), setScaleDivFromAxis()
QPalette QwtPlotScaleItem::palette ( ) const
See also
double QwtPlotScaleItem::position ( ) const
Position of the scale
See also
setPosition(), setAlignment()
int QwtPlotScaleItem::rtti ( ) const

Reimplemented from QwtPlotItem.

const QwtScaleDiv & QwtPlotScaleItem::scaleDiv ( ) const
Scale division
const QwtScaleDraw * QwtPlotScaleItem::scaleDraw ( ) const
Scale draw
See also
QwtScaleDraw * QwtPlotScaleItem::scaleDraw ( )
Scale draw
See also
void QwtPlotScaleItem::setAlignment ( QwtScaleDraw::Alignment  alignment)

Change the alignment of the scale

The alignment sets the orientation of the scale and the position of the ticks:

For horizontal scales the position corresponds to QwtPlotItem::yAxis(), otherwise to QwtPlotItem::xAxis().

See also
scaleDraw(), QwtScaleDraw::alignment(), setPosition()
void QwtPlotScaleItem::setBorderDistance ( int  distance)

Align the scale to the canvas.

If distance is >= 0 the scale will be aligned to a border of the contents rectangle of the canvas. If alignment() is QwtScaleDraw::LeftScale, the scale will be aligned to the right border, if it is QwtScaleDraw::TopScale it will be aligned to the bottom (and vice versa),

If distance is < 0 the scale will be at the position().

distanceNumber of pixels between the canvas border and the backbone of the scale.
See also
setPosition(), borderDistance()
void QwtPlotScaleItem::setFont ( const QFont &  font)

Change the tick label font

See also
void QwtPlotScaleItem::setPalette ( const QPalette &  palette)

Set the palette

See also
QwtAbstractScaleDraw::draw(), palette()
void QwtPlotScaleItem::setPosition ( double  pos)

Change the position of the scale

The position is interpreted as y value for horizontal axes and as x value for vertical axes.

The border distance is set to -1.

posNew position
See also
position(), setAlignment()
void QwtPlotScaleItem::setScaleDiv ( const QwtScaleDiv scaleDiv)

Assign a scale division.

When assigning a scaleDiv the scale division won't be synchronized with the corresponding axis anymore.

scaleDivScale division
See also
scaleDiv(), setScaleDivFromAxis(), isScaleDivFromAxis()
void QwtPlotScaleItem::setScaleDivFromAxis ( bool  on)

Enable/Disable the synchronization of the scale division with the corresponding axis.

See also
void QwtPlotScaleItem::setScaleDraw ( QwtScaleDraw scaleDraw)

Set a scale draw.

scaleDrawobject responsible for drawing scales.

The main use case for replacing the default QwtScaleDraw is to overload QwtAbstractScaleDraw::label, to replace or swallow tick labels.

See also
void QwtPlotScaleItem::updateScaleDiv ( const QwtScaleDiv xScaleDiv,
const QwtScaleDiv yScaleDiv 

Update the item to changes of the axes scale division.

In case of isScaleDivFromAxis(), the scale draw is synchronized to the correspond axis.

xScaleDivScale division of the x-axis
yScaleDivScale division of the y-axis
See also

Reimplemented from QwtPlotItem.