Qwt User's Guide 5.2.2
Public Types | Public Slots | Public Member Functions | Protected Member Functions

QwtThermo Class Reference

The Thermometer Widget. More...

#include <qwt_thermo.h>

Inheritance diagram for QwtThermo:
Inheritance graph
[legend]

List of all members.

Public Types

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

Public Slots

void setValue (double val)

Public Member Functions

const QBrush & alarmBrush () const
const QColor & alarmColor () const
bool alarmEnabled () const
double alarmLevel () const
bool autoScale () const
int borderWidth () const
const QBrush & fillBrush () const
const QColor & fillColor () const
double maxValue () const
virtual QSize minimumSizeHint () const
double minValue () const
int pipeWidth () const
 QwtThermo (QWidget *parent=NULL)
const QwtScaleDrawscaleDraw () const
const QwtScaleEnginescaleEngine () const
QwtScaleEnginescaleEngine ()
const QwtScaleMapscaleMap () const
int scaleMaxMajor () const
int scaleMaxMinor () const
ScalePos scalePosition () const
void setAlarmBrush (const QBrush &b)
void setAlarmColor (const QColor &c)
void setAlarmEnabled (bool tf)
void setAlarmLevel (double v)
void setAutoScale ()
void setBorderWidth (int w)
void setFillBrush (const QBrush &b)
void setFillColor (const QColor &c)
void setMargin (int m)
void setMaxValue (double v)
void setMinValue (double v)
void setOrientation (Qt::Orientation o, ScalePos s)
void setPipeWidth (int w)
void setRange (double vmin, double vmax, bool lg=false)
void setScale (double vmin, double vmax, double step=0.0)
void setScale (const QwtScaleDiv &s)
void setScale (const QwtDoubleInterval &, double step=0.0)
void setScaleDraw (QwtScaleDraw *)
void setScaleEngine (QwtScaleEngine *)
void setScaleMaxMajor (int ticks)
void setScaleMaxMinor (int ticks)
void setScalePosition (ScalePos s)
virtual QSize sizeHint () const
double value () const
virtual ~QwtThermo ()

Protected Member Functions

const QwtAbstractScaleDrawabstractScaleDraw () const
QwtAbstractScaleDrawabstractScaleDraw ()
void draw (QPainter *p, const QRect &update_rect)
void drawThermo (QPainter *p)
virtual void fontChange (const QFont &oldFont)
void layoutThermo (bool update=true)
virtual void paintEvent (QPaintEvent *e)
void rescale (double vmin, double vmax, double step=0.0)
virtual void resizeEvent (QResizeEvent *e)
virtual void scaleChange ()
QwtScaleDrawscaleDraw ()
void setAbstractScaleDraw (QwtAbstractScaleDraw *)

Detailed Description

The Thermometer Widget.

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

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:
parentParent widget
QwtThermo::~QwtThermo ( ) [virtual]

Destructor.


Member Function Documentation

const QwtAbstractScaleDraw * QwtAbstractScale::abstractScaleDraw ( ) const [protected, inherited]
Returns:
Scale draw
See also:
setAbstractScaleDraw()
QwtAbstractScaleDraw * QwtAbstractScale::abstractScaleDraw ( ) [protected, inherited]
Returns:
Scale draw
See also:
setAbstractScaleDraw()
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()
bool QwtAbstractScale::autoScale ( ) const [inherited]
Returns:
true if autoscaling is enabled
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:
painterPainter
rectUpdate rectangle
void QwtThermo::drawThermo ( QPainter *  painter) [protected]

Redraw the liquid in thermometer pipe.

Parameters:
painterPainter
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_geometrynotify 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 QwtAbstractScale::rescale ( double  vmin,
double  vmax,
double  stepSize = 0.0 
) [protected, inherited]

Recalculate the scale division and update the scale draw.

Parameters:
vminLower limit of the scale interval
vmaxUpper limit of the scale interval
stepSizeMajor step size
See also:
scaleChange()
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()
const QwtScaleEngine * QwtAbstractScale::scaleEngine ( ) const [inherited]
Returns:
Scale engine
See also:
setScaleEngine()
QwtScaleEngine * QwtAbstractScale::scaleEngine ( ) [inherited]
Returns:
Scale engine
See also:
setScaleEngine()
const QwtScaleMap & QwtAbstractScale::scaleMap ( ) const [inherited]
int QwtAbstractScale::scaleMaxMajor ( ) const [inherited]
Returns:
Max. number of major tick intervals The default value is 5.
int QwtAbstractScale::scaleMaxMinor ( ) const [inherited]
Returns:
Max. number of minor tick intervals The default value is 3.
QwtThermo::ScalePos QwtThermo::scalePosition ( ) const

Return the scale position.

See also:
setScalePosition()
void QwtAbstractScale::setAbstractScaleDraw ( QwtAbstractScaleDraw scaleDraw) [protected, inherited]

Set a scale draw.

scaleDraw has to be created with new and will be deleted in ~QwtAbstractScale or the next call of setAbstractScaleDraw.

void QwtThermo::setAlarmBrush ( const QBrush &  brush)

Specify the liquid brush above the alarm threshold.

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

Specify the liquid color above the alarm threshold.

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

Enable or disable the alarm threshold.

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

Specify the alarm threshold.

Parameters:
levelAlarm threshold
See also:
alarmLevel()
void QwtAbstractScale::setAutoScale ( ) [inherited]

Advise the widget to control the scale range internally.

Autoscaling is on by default.

See also:
setScale(), autoScale()
void QwtThermo::setBorderWidth ( int  width)

Set the border width of the pipe.

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

Change the brush of the liquid.

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

Change the color of the liquid.

Parameters:
cNew 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:
mNew 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:
maxMaximum value
See also:
maxValue(), setMinValue()
void QwtThermo::setMinValue ( double  min)

Set the minimum value.

Parameters:
minMinimum 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:
oorientation. Possible values are Qt::Horizontal and Qt::Vertical. The default value is Qt::Vertical.
sPosition 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:
widthWidth of the pipe
See also:
pipeWidth()
void QwtThermo::setRange ( double  vmin,
double  vmax,
bool  logarithmic = false 
)

Set the range.

Parameters:
vminvalue corresponding lower or left end of the thermometer
vmaxvalue corresponding to the upper or right end of the thermometer
logarithmiclogarithmic mapping, true or false
void QwtAbstractScale::setScale ( const QwtDoubleInterval interval,
double  stepSize = 0.0 
) [inherited]

Specify a scale.

Disable autoscaling and define a scale by an interval and a step size

Parameters:
intervalInterval
stepSizemajor step size
See also:
setAutoScale()
void QwtAbstractScale::setScale ( const QwtScaleDiv scaleDiv) [inherited]

Specify a scale.

Disable autoscaling and define a scale by a scale division

Parameters:
scaleDivScale division
See also:
setAutoScale()
void QwtAbstractScale::setScale ( double  vmin,
double  vmax,
double  stepSize = 0.0 
) [inherited]

Specify a scale.

Disable autoscaling and define a scale by an interval and a step size

Parameters:
vminlower limit of the scale interval
vmaxupper limit of the scale interval
stepSizemajor step size
See also:
setAutoScale()
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:
scaleDrawScaleDraw object, that has to be created with new and will be deleted in ~QwtThermo or the next call of setScaleDraw().
void QwtAbstractScale::setScaleEngine ( QwtScaleEngine scaleEngine) [inherited]

Set a scale engine.

The scale engine is responsible for calculating the scale division, and in case of auto scaling how to align the scale.

scaleEngine has to be created with new and will be deleted in ~QwtAbstractScale or the next call of setScaleEngine.

void QwtAbstractScale::setScaleMaxMajor ( int  ticks) [inherited]

Set the maximum number of major tick intervals.

The scale's major ticks are calculated automatically such that the number of major intervals does not exceed ticks. The default value is 5.

Parameters:
ticksmaximal number of major ticks.
See also:
QwtAbstractScaleDraw
void QwtAbstractScale::setScaleMaxMinor ( int  ticks) [inherited]

Set the maximum number of minor tick intervals.

The scale's minor ticks are calculated automatically such that the number of minor intervals does not exceed ticks. The default value is 3.

Parameters:
ticks
See also:
QwtAbstractScaleDraw
void QwtThermo::setScalePosition ( ScalePos  scalePos)

Change the scale position (and thermometer orientation).

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

Return the value.