QwtPlotScaleItem Class Reference

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

#include <qwt_plot_scaleitem.h>

Inheritance diagram for QwtPlotScaleItem:
Inheritance graph
[legend]

List of all members.

Public Member Functions

 QwtPlotScaleItem (QwtScaleDraw::Alignment=QwtScaleDraw::BottomScale, const double pos=0.0)
virtual ~QwtPlotScaleItem ()
virtual int rtti () const
void setScaleDiv (const QwtScaleDiv &)
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 *)
const QwtScaleDrawscaleDraw () const
QwtScaleDrawscaleDraw ()
void setPosition (double pos)
double position () const
void setBorderDistance (int numPixels)
int borderDistance () const
void setAlignment (QwtScaleDraw::Alignment)
virtual void draw (QPainter *p, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRect &rect) const
virtual void updateScaleDiv (const QwtScaleDiv &, const QwtScaleDiv &)

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.

Example
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);
scaleItem->setFont(plot->axisWidget(QwtPlot::yLeft)->font());
scaleItem->attach(plot);

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

Constructor & Destructor Documentation

QwtPlotScaleItem::QwtPlotScaleItem ( QwtScaleDraw::Alignment  alignment = QwtScaleDraw::BottomScale,
const double  pos = 0.0 
) [explicit]

Constructor for scale item at the position pos.

Parameters:
alignment In case of QwtScaleDraw::BottomScale/QwtScaleDrawTopScale the scale item is corresponding to the xAxis(), otherwise it corresponds to the yAxis().
pos x or y position, depending on the corresponding axis.
See also:
setPosition(), setAlignment()
QwtPlotScaleItem::~QwtPlotScaleItem (  )  [virtual]

Destructor.


Member Function Documentation

int QwtPlotScaleItem::borderDistance (  )  const
Returns:
Distance from a canvas border
See also:
setBorderDistance(), setPosition()
void QwtPlotScaleItem::draw ( QPainter *  p,
const QwtScaleMap xMap,
const QwtScaleMap yMap,
const QRect &  rect 
) const [virtual]

Draw the scale.

Implements QwtPlotItem.

QFont QwtPlotScaleItem::font (  )  const
Returns:
tick label font
See also:
setFont()
bool QwtPlotScaleItem::isScaleDivFromAxis (  )  const
Returns:
True, if the synchronization of the scale division with the corresponding axis is enabled.
See also:
setScaleDiv(), setScaleDivFromAxis()
QPalette QwtPlotScaleItem::palette (  )  const
Returns:
palette
See also:
setPalette()
double QwtPlotScaleItem::position (  )  const
Returns:
Position of the scale
See also:
setPosition(), setAlignment()
int QwtPlotScaleItem::rtti (  )  const [virtual]
Returns:
QwtPlotItem::Rtti_PlotScale

Reimplemented from QwtPlotItem.

const QwtScaleDiv & QwtPlotScaleItem::scaleDiv (  )  const
Returns:
Scale division
QwtScaleDraw * QwtPlotScaleItem::scaleDraw (  ) 
Returns:
Scale draw
See also:
setScaleDraw()
const QwtScaleDraw * QwtPlotScaleItem::scaleDraw (  )  const
Returns:
Scale draw
See also:
setScaleDraw()
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:

  • QwtScaleDraw::BottomScale: horizontal, ticks below
  • QwtScaleDraw::TopScale: horizontal, ticks above
  • QwtScaleDraw::LeftScale: vertical, ticks left
  • QwtScaleDraw::RightScale: vertical, ticks right

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 rect 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().

Parameters:
distance Number 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:
font()
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.

Parameters:
pos New 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.

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

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

Parameters:
on true/false
See also:
isScaleDivFromAxis()
void QwtPlotScaleItem::setScaleDraw ( QwtScaleDraw scaleDraw  ) 

Set a scale draw.

Parameters:
scaleDraw object 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:
scaleDraw()
void QwtPlotScaleItem::updateScaleDiv ( const QwtScaleDiv xScaleDiv,
const QwtScaleDiv yScaleDiv 
) [virtual]

Update the item to changes of the axes scale division.

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

Parameters:
xScaleDiv Scale division of the x-axis
yScaleDiv Scale division of the y-axis
See also:
QwtPlot::updateAxes()

Reimplemented from QwtPlotItem.

Generated on Sun Apr 11 11:56:11 2010 for Qwt User's Guide by  doxygen 1.6.3