Qwt User's Guide: QwtThermo Class Reference

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QwtThermo Class Reference

The Thermometer Widget. More...

#include <qwt_thermo.h>

Inheritance diagram for QwtThermo:
[legend]

List of all members.

Public Types

enum  ScalePos {
  NoScale,
  LeftScale,
  RightScale,
  TopScale,
  BottomScale
}

Public Slots

void setValue (double val)

Public Member Functions

 QwtThermo (QWidget *parent=NULL)
virtual ~QwtThermo ()
void setOrientation (Qt::Orientation o, ScalePos s)
void setScalePosition (ScalePos s)
ScalePos scalePosition () const
void setBorderWidth (int w)
int borderWidth () const
void setFillBrush (const QBrush &b)
const QBrush & fillBrush () const
void setFillColor (const QColor &c)
const QColor & fillColor () const
void setAlarmBrush (const QBrush &b)
const QBrush & alarmBrush () const
void setAlarmColor (const QColor &c)
const QColor & alarmColor () const
void setAlarmLevel (double v)
double alarmLevel () const
void setAlarmEnabled (bool tf)
bool alarmEnabled () const
void setPipeWidth (int w)
int pipeWidth () const
void setMaxValue (double v)
double maxValue () const
void setMinValue (double v)
double minValue () const
double value () const
void setRange (double vmin, double vmax, bool lg=false)
void setMargin (int m)
virtual QSize sizeHint () const
virtual QSize minimumSizeHint () const
void setScaleDraw (QwtScaleDraw *)
const QwtScaleDraw * scaleDraw () const

Protected Member Functions

void draw (QPainter *p, const QRect &update_rect)
void drawThermo (QPainter *p)
void layoutThermo (bool update=true)
virtual void scaleChange ()
virtual void fontChange (const QFont &oldFont)
virtual void paintEvent (QPaintEvent *e)
virtual void resizeEvent (QResizeEvent *e)
QwtScaleDraw * scaleDraw ()

Detailed Description

The Thermometer Widget.

QwtThermo is a widget which displays a value in an interval. It supports:

  • a horizontal or vertical layout;
  • a range;
  • a scale;
  • an alarm level.
sysinfo.png

By default, the scale and range run over the same interval of values. QwtAbstractScale::setScale() changes the interval of the scale and allows easy conversion between physical units.

The example shows how to make the scale indicate in degrees Fahrenheit and to set the value in degrees Kelvin: 

#include <qapplication.h>
#include <qwt_thermo.h>

double Kelvin2Fahrenheit(double kelvin)
{
    // see http://en.wikipedia.org/wiki/Kelvin
    return 1.8*kelvin - 459.67;
}

int main(int argc, char **argv)
{
    const double minKelvin = 0.0;
    const double maxKelvin = 500.0;

    QApplication a(argc, argv);
    QwtThermo t;
    t.setRange(minKelvin, maxKelvin);
    t.setScale(Kelvin2Fahrenheit(minKelvin), Kelvin2Fahrenheit(maxKelvin));
    // set the value in Kelvin but the scale displays in Fahrenheit
    // 273.15 Kelvin = 0 Celsius = 32 Fahrenheit
    t.setValue(273.15);
    a.setMainWidget(&t);
    t.show();
    return a.exec();
}

Constructor & Destructor Documentation

QwtThermo::QwtThermo ( QWidget *  parent = NULL  )  [explicit]

Constructor

Parameters:
parent Parent widget
QwtThermo::~QwtThermo (  )  [virtual]

Destructor.

Member Function Documentation

const QBrush & QwtThermo::alarmBrush (  )  const

Return the liquid brush above the alarm threshold.

See also:
setAlarmBrush()
const QColor & QwtThermo::alarmColor (  )  const

Return the liquid color above the alarm threshold.

bool QwtThermo::alarmEnabled (  )  const

Return if the alarm threshold is enabled or disabled.

double QwtThermo::alarmLevel (  )  const

Return the alarm threshold.

See also:
setAlarmLevel()
int QwtThermo::borderWidth (  )  const

Return the border width of the thermometer pipe.

See also:
setBorderWidth()
void QwtThermo::draw ( QPainter *  painter,
const QRect &  rect 
) [protected]

Draw the whole QwtThermo.

Parameters:
painter Painter
rect Update rectangle
void QwtThermo::drawThermo ( QPainter *  painter  )  [protected]

Redraw the liquid in thermometer pipe.

Parameters:
painter Painter
const QBrush & QwtThermo::fillBrush (  )  const

Return the liquid brush.

See also:
setFillBrush()
const QColor & QwtThermo::fillColor (  )  const

Return the liquid color.

See also:
setFillColor()
void QwtThermo::fontChange ( const QFont &  oldFont  )  [protected, virtual]

Notify a font change.

void QwtThermo::layoutThermo ( bool  update_geometry = true  )  [protected]

Recalculate the QwtThermo geometry and layout based on the QwtThermo::rect() and the fonts.

Parameters:
update_geometry notify the layout system and call update to redraw the scale
double QwtThermo::maxValue (  )  const

Return the maximum value.

QSize QwtThermo::minimumSizeHint (  )  const [virtual]

Return a minimum size hint.

Warning:
The return value depends on the font and the scale.
See also:
sizeHint()
double QwtThermo::minValue (  )  const

Return the minimum value.

void QwtThermo::paintEvent ( QPaintEvent *  event  )  [protected, virtual]

Qt paint event. event Paint event

int QwtThermo::pipeWidth (  )  const

Return the width of the pipe.

See also:
setPipeWidth()
void QwtThermo::resizeEvent ( QResizeEvent *  e  )  [protected, virtual]

Qt resize event handler.

void QwtThermo::scaleChange (  )  [protected, virtual]

Notify a scale change.

Reimplemented from QwtAbstractScale.

QwtScaleDraw * QwtThermo::scaleDraw (  )  [protected]
Returns:
the scale draw of the thermo
See also:
setScaleDraw()
const QwtScaleDraw * QwtThermo::scaleDraw (  )  const
Returns:
the scale draw of the thermo
See also:
setScaleDraw()
QwtThermo::ScalePos QwtThermo::scalePosition (  )  const

Return the scale position.

See also:
setScalePosition()
void QwtThermo::setAlarmBrush ( const QBrush &  brush  ) 

Specify the liquid brush above the alarm threshold.

Parameters:
brush New brush. The default is solid white.
See also:
alarmBrush()
void QwtThermo::setAlarmColor ( const QColor &  c  ) 

Specify the liquid color above the alarm threshold.

Parameters:
c New color. The default is white.
void QwtThermo::setAlarmEnabled ( bool  tf  ) 

Enable or disable the alarm threshold.

Parameters:
tf true (disabled) or false (enabled)
void QwtThermo::setAlarmLevel ( double  level  ) 

Specify the alarm threshold.

Parameters:
level Alarm threshold
See also:
alarmLevel()
void QwtThermo::setBorderWidth ( int  width  ) 

Set the border width of the pipe.

Parameters:
width Border width
See also:
borderWidth()
void QwtThermo::setFillBrush ( const QBrush &  brush  ) 

Change the brush of the liquid.

Parameters:
brush New brush. The default brush is solid black.
See also:
fillBrush()
void QwtThermo::setFillColor ( const QColor &  c  ) 

Change the color of the liquid.

Parameters:
c New color. The default color is black.
See also:
fillColor()
void QwtThermo::setMargin ( int  m  ) 

Specify the distance between the pipe's endpoints and the widget's border.

The margin is used to leave some space for the scale labels. If a large font is used, it is advisable to adjust the margins.

Parameters:
m New Margin. The default values are 10 for horizontal orientation and 20 for vertical orientation.
Warning:
The margin has no effect if the scale is disabled.
This function is a NOOP because margins are determined automatically.
void QwtThermo::setMaxValue ( double  max  ) 

Set the maximum value.

Parameters:
max Maximum value
See also:
maxValue(), setMinValue()
void QwtThermo::setMinValue ( double  min  ) 

Set the minimum value.

Parameters:
min Minimum value
See also:
minValue(), setMaxValue()
void QwtThermo::setOrientation ( Qt::Orientation  o,
ScalePos  s 
)

Set the thermometer orientation and the scale position.

The scale position NoScale disables the scale.

Parameters:
o orientation. Possible values are Qt::Horizontal and Qt::Vertical. The default value is Qt::Vertical.
s Position of the scale. The default value is NoScale.

A valid combination of scale position and orientation is enforced:

  • a horizontal thermometer can have the scale positions TopScale, BottomScale or NoScale;
  • a vertical thermometer can have the scale positions LeftScale, RightScale or NoScale;
  • an invalid scale position will default to NoScale.
See also:
setScalePosition()
void QwtThermo::setPipeWidth ( int  width  ) 

Change the width of the pipe.

Parameters:
width Width of the pipe
See also:
pipeWidth()
void QwtThermo::setRange ( double  vmin,
double  vmax,
bool  logarithmic = false 
)

Set the range.

Parameters:
vmin value corresponding lower or left end of the thermometer
vmax value corresponding to the upper or right end of the thermometer
logarithmic logarithmic mapping, true or false
void QwtThermo::setScaleDraw ( QwtScaleDraw *  scaleDraw  ) 

Set a scale draw.

For changing the labels of the scales, it is necessary to derive from QwtScaleDraw and overload QwtScaleDraw::label().

Parameters:
scaleDraw ScaleDraw object, that has to be created with new and will be deleted in ~QwtThermo or the next call of setScaleDraw().
void QwtThermo::setScalePosition ( ScalePos  scalePos  ) 

Change the scale position (and thermometer orientation).

Parameters:
scalePos Position of the scale.

A valid combination of scale position and orientation is enforced:

  • if the new scale position is LeftScale or RightScale, the scale orientation will become Qt::Vertical;
  • if the new scale position is BottomScale or TopScale, the scale orientation will become Qt::Horizontal;
  • if the new scale position is NoScale, the scale orientation will not change.
See also:
setOrientation(), scalePosition()
void QwtThermo::setValue ( double  value  )  [slot]

Set the current value.

Parameters:
value New Value
See also:
value()
QSize QwtThermo::sizeHint (  )  const [virtual]
Returns:
the minimum size hint
See also:
minimumSizeHint()
double QwtThermo::value (  )  const

Return the value.

Generated on Wed Sep 2 18:37:28 2009 for Qwt User's Guide by  doxygen 1.6.1
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