Qwt User's Guide
QwtCounter Class Reference

The Counter Widget. More...

#include <qwt_counter.h>

Public Types

enum  Button { Button1, Button2, Button3, ButtonCnt }
 Button index. More...

Public Slots

void setValue (double)
 Set a new value without adjusting to the step raster.

Signals

void buttonReleased (double value)
void valueChanged (double value)

Public Member Functions

 QwtCounter (QWidget *parent=NULL)
virtual ~QwtCounter ()
 Destructor.
void setValid (bool)
bool isValid () const
void setWrapping (bool)
 En/Disable wrapping.
bool wrapping () const
bool isReadOnly () const
void setReadOnly (bool)
 Allow/disallow the user to manually edit the value.
void setNumButtons (int n)
int numButtons () const
void setIncSteps (QwtCounter::Button btn, int nSteps)
int incSteps (QwtCounter::Button btn) const
virtual QSize sizeHint () const
 A size hint.
double singleStep () const
void setSingleStep (double s)
 Set the step size of the counter.
void setRange (double min, double max)
 Set the minimum and maximum values.
double minimum () const
void setMinimum (double min)
double maximum () const
void setMaximum (double max)
void setStepButton1 (int nSteps)
int stepButton1 () const
 returns the number of increment steps for button 1
void setStepButton2 (int nSteps)
int stepButton2 () const
 returns the number of increment steps for button 2
void setStepButton3 (int nSteps)
int stepButton3 () const
 returns the number of increment steps for button 3
double value () const

Protected Member Functions

virtual bool event (QEvent *)
virtual void wheelEvent (QWheelEvent *)
virtual void keyPressEvent (QKeyEvent *)

Detailed Description

The Counter Widget.

A Counter consists of a label displaying a number and one ore more (up to three) push buttons on each side of the label which can be used to increment or decrement the counter's value.

A counter has a range from a minimum value to a maximum value and a step size. When the wrapping property is set the counter is circular.

The number of steps by which a button increments or decrements the value can be specified using setIncSteps(). The number of buttons can be changed with setNumButtons().

Example:

#include <qwt_counter.h>

QwtCounter *counter = new QwtCounter(parent);

counter->setRange(0.0, 100.0);                  // From 0.0 to 100
counter->setSingleStep( 1.0 );                  // Step size 1.0
counter->setNumButtons(2);                      // Two buttons each side
counter->setIncSteps(QwtCounter::Button1, 1);   // Button 1 increments 1 step
counter->setIncSteps(QwtCounter::Button2, 20);  // Button 2 increments 20 steps

connect(counter, SIGNAL(valueChanged(double)), myClass, SLOT(newValue(double)));

Member Enumeration Documentation

Button index.

Enumerator:
Button1 

Button intended for minor steps.

Button2 

Button intended for medium steps.

Button3 

Button intended for large steps.

ButtonCnt 

Number of buttons.


Constructor & Destructor Documentation

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

The counter is initialized with a range is set to [0.0, 1.0] with 0.01 as single step size. The value is invalid.

The default number of buttons is set to 2. The default increments are:

  • Button 1: 1 step
  • Button 2: 10 steps
  • Button 3: 100 steps
Parameters:
parent

Member Function Documentation

void QwtCounter::buttonReleased ( double  value) [signal]

This signal is emitted when a button has been released

Parameters:
valueThe new value
bool QwtCounter::event ( QEvent *  event) [protected, virtual]

Handle QEvent::PolishRequest events

Parameters:
eventEvent
Returns:
see QWidget::event()
Returns:
The number of steps by which a specified button increments the value or 0 if the button is invalid.
Parameters:
buttonButton index
See also:
setIncSteps()
bool QwtCounter::isReadOnly ( ) const
Returns:
True, when the line line edit is read only. (default is no)
See also:
setReadOnly()
bool QwtCounter::isValid ( ) const
Returns:
True, if the value is valid
See also:
setValid(), setValue()
void QwtCounter::keyPressEvent ( QKeyEvent *  event) [protected, virtual]

Handle key events

  • Ctrl + Qt::Key_Home
    Step to minimum()
  • Ctrl + Qt::Key_End
    Step to maximum()
  • Qt::Key_Up
    Increment by incSteps(QwtCounter::Button1)
  • Qt::Key_Down
    Decrement by incSteps(QwtCounter::Button1)
  • Qt::Key_PageUp
    Increment by incSteps(QwtCounter::Button2)
  • Qt::Key_PageDown
    Decrement by incSteps(QwtCounter::Button2)
  • Shift + Qt::Key_PageUp
    Increment by incSteps(QwtCounter::Button3)
  • Shift + Qt::Key_PageDown
    Decrement by incSteps(QwtCounter::Button3)
Parameters:
eventKey event
double QwtCounter::maximum ( ) const
Returns:
The maximum of the range
See also:
setRange(), setMaximum(), minimum()
double QwtCounter::minimum ( ) const
Returns:
The minimum of the range
See also:
setRange(), setMinimum(), maximum()
int QwtCounter::numButtons ( ) const
Returns:
The number of buttons on each side of the widget.
See also:
setNumButtons()
void QwtCounter::setIncSteps ( QwtCounter::Button  button,
int  numSteps 
)

Specify the number of steps by which the value is incremented or decremented when a specified button is pushed.

Parameters:
buttonButton index
numStepsNumber of steps
See also:
incSteps()
void QwtCounter::setMaximum ( double  value)

Set the maximum value of the range

Parameters:
valueMaximum value
See also:
setRange(), setMinimum(), maximum()
void QwtCounter::setMinimum ( double  value)

Set the minimum value of the range

Parameters:
valueMinimum value
See also:
setRange(), setMaximum(), minimum()
Note:
The maximum is adjusted if necessary to ensure that the range remains valid.
void QwtCounter::setNumButtons ( int  numButtons)

Specify the number of buttons on each side of the label

Parameters:
numButtonsNumber of buttons
See also:
numButtons()
void QwtCounter::setRange ( double  min,
double  max 
)

Set the minimum and maximum values.

The maximum is adjusted if necessary to ensure that the range remains valid. The value might be modified to be inside of the range.

Parameters:
minMinimum value
maxMaximum value
See also:
minimum(), maximum()
void QwtCounter::setReadOnly ( bool  on)

Allow/disallow the user to manually edit the value.

Parameters:
onTrue disable editing
See also:
isReadOnly()
void QwtCounter::setSingleStep ( double  stepSize)

Set the step size of the counter.

A value <= 0.0 disables stepping

Parameters:
stepSizeSingle step size
See also:
singleStep()
void QwtCounter::setStepButton1 ( int  nSteps)

Set the number of increment steps for button 1

Parameters:
nStepsNumber of steps
void QwtCounter::setStepButton2 ( int  nSteps)

Set the number of increment steps for button 2

Parameters:
nStepsNumber of steps
void QwtCounter::setStepButton3 ( int  nSteps)

Set the number of increment steps for button 3

Parameters:
nStepsNumber of steps
void QwtCounter::setValid ( bool  on)

Set the counter to be in valid/invalid state

When the counter is set to invalid, no numbers are displayed and the buttons are disabled.

Parameters:
onIf true the counter will be set as valid
See also:
setValue(), isValid()
void QwtCounter::setValue ( double  value) [slot]

Set a new value without adjusting to the step raster.

The state of the counter is set to be valid.

Parameters:
valueNew value
See also:
isValid(), value(), valueChanged()
Warning:
The value is clipped when it lies outside the range.
void QwtCounter::setWrapping ( bool  on)

En/Disable wrapping.

If wrapping is true stepping up from maximum() value will take you to the minimum() value and vice versa.

Parameters:
onEn/Disable wrapping
See also:
wrapping()
double QwtCounter::singleStep ( ) const
Returns:
Single step size
See also:
setSingleStep()
double QwtCounter::value ( ) const
Returns:
Current value of the counter
See also:
setValue(), valueChanged()
void QwtCounter::valueChanged ( double  value) [signal]

This signal is emitted when the counter's value has changed

Parameters:
valueThe new value
void QwtCounter::wheelEvent ( QWheelEvent *  event) [protected, virtual]

Handle wheel events

Parameters:
eventWheel event
bool QwtCounter::wrapping ( ) const
Returns:
True, when wrapping is set
See also:
setWrapping()

List of all members.

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