QwtCounter Class Reference

#include <qwt_counter.h>

Inherits QwtDoubleRange.

List of all members.

Public Types
enum	Button {   Button1,   Button2,   Button3,   ButtonCnt }
Signals
void	buttonReleased (double value)
void	valueChanged (double value)
Public Member Functions
bool	editable () const
virtual void	fitValue (double)
virtual void	incPages (int)
int	incSteps (QwtCounter::Button btn) const
virtual void	incValue (int)
bool	isValid () const
double	maxValue () const
double	minValue () const
int	numButtons () const
int	pageSize () const
bool	periodic () const
	QwtCounter (QWidget *parent=NULL)
void	setEditable (bool)
void	setIncSteps (QwtCounter::Button btn, int nSteps)
void	setMaxValue (double m)
void	setMinValue (double m)
void	setNumButtons (int n)
void	setPeriodic (bool tf)
void	setRange (double vmin, double vmax, double vstep=0.0, int pagesize=1)
void	setStep (double s)
void	setStepButton1 (int nSteps)
void	setStepButton2 (int nSteps)
void	setStepButton3 (int nSteps)
void	setValid (bool)
virtual void	setValue (double)
virtual QSize	sizeHint () const
double	step () const
int	stepButton1 () const
int	stepButton2 () const
int	stepButton3 () const
virtual double	value () const
virtual	~QwtCounter ()
Protected Member Functions
virtual bool	event (QEvent *)
double	exactPrevValue () const
double	exactValue () const
virtual void	keyPressEvent (QKeyEvent *)
double	prevValue () const
virtual void	rangeChange ()
virtual void	stepChange ()
virtual void	wheelEvent (QWheelEvent *)

---

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. The range can be specified using QwtDblRange::setRange(). The counter's value is an integer multiple of the step size. The number of steps by which a button increments or decrements the value can be specified using QwtCounter::setIncSteps(). The number of buttons can be changed with QwtCounter::setNumButtons().

Holding the space bar down with focus on a button is the fastest method to step through the counter values. When the counter underflows/overflows, the focus is set to the smallest up/down button and counting is disabled. Counting is re-enabled on a button release event (mouse or space bar).

Example:

#include "../include/qwt_counter.h>

QwtCounter *cnt;

cnt = new QwtCounter(parent, name);

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

connect(cnt, SIGNAL(valueChanged(double)), my_class, SLOT(newValue(double)));

---

Member Enumeration Documentation

enum QwtCounter::Button

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 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

QwtCounter::~QwtCounter

(

)

[virtual]

Destructor.

---

Member Function Documentation

void QwtCounter::buttonReleased

(

double

value

)

[signal]

This signal is emitted when a button has been released

Parameters:

value

The new value

bool QwtCounter::editable

(

)

const

returns whether the line edit is edatble. (default is yes)

bool QwtCounter::event

(

QEvent *

event

)

[protected, virtual]

Handle PolishRequest events

Parameters:

event

Event

double QwtDoubleRange::exactPrevValue

(

)

const [protected, inherited]

Returns the exact previous value.

double QwtDoubleRange::exactValue

(

)

const [protected, inherited]

Returns the exact value.

The exact value is the value which QwtDoubleRange::value would return if the value were not adjusted to the step raster. It differs from the current value only if fitValue() or incValue() have been used before. This function is intended for internal use in derived classes.

void QwtDoubleRange::fitValue

(

double

x

)

[virtual, inherited]

Adjust the value to the closest point in the step raster.

Parameters:

x

value

Warning:

The value is clipped when it lies outside the range. When the range is QwtDoubleRange::periodic, it will be mapped to a point in the interval such that

new value := x + n * (max. value - min. value)

with an integer number n.

Reimplemented in QwtAbstractSlider.

void QwtDoubleRange::incPages

(

int

nPages

)

[virtual, inherited]

Increment the value by a specified number of pages.

Parameters:

nPages

Number of pages to increment. A negative number decrements the value.

Warning:

The Page size is specified in the constructor.

int QwtCounter::incSteps

(

QwtCounter::Button

button

)

const

Returns:

the number of steps by which a specified button increments the value or 0 if the button is invalid.

Parameters:

button

Button index

See also:

setIncSteps()

void QwtDoubleRange::incValue

(

int

nSteps

)

[virtual, inherited]

Increment the value by a specified number of steps.

Parameters:

nSteps

Number of steps to increment

Warning:

As a result of this operation, the new value will always be adjusted to the step raster.

Reimplemented in QwtAbstractSlider.

bool QwtDoubleRange::isValid

(

)

const [inherited]

Indicates if the value is valid.

Reimplemented in QwtAbstractSlider.

void QwtCounter::keyPressEvent

(

QKeyEvent *

event

)

[protected, virtual]

Handle key events

• Ctrl + Qt::Key_Home
  Step to minValue()
• Ctrl + Qt::Key_End
  Step to maxValue()
• 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:

event

Key event

double QwtCounter::maxValue

(

)

const

returns the maximum value of the range

Reimplemented from QwtDoubleRange.

double QwtCounter::minValue

(

)

const

returns the minimum value of the range

Reimplemented from QwtDoubleRange.

int QwtCounter::numButtons

(

)

const

Returns:

The number of buttons on each side of the widget.

int QwtDoubleRange::pageSize

(

)

const [inherited]

Returns the page size in steps.

bool QwtDoubleRange::periodic

(

)

const [inherited]

Returns true if the range is periodic.

See also:

setPeriodic()

double QwtDoubleRange::prevValue

(

)

const [protected, inherited]

Returns the previous value.

void QwtCounter::rangeChange

(

)

[protected, virtual]

Notify change of range.

This function updates the enabled property of all buttons contained in QwtCounter.

Reimplemented from QwtDoubleRange.

void QwtCounter::setEditable

(

bool

editable

)

Allow/disallow the user to manually edit the value.

Parameters:

editable

true enables editing

See also:

editable()

void QwtCounter::setIncSteps	(	QwtCounter::Button	button,
		int	nSteps
	)

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

Parameters:

button	Button index
nSteps	Number of steps

See also:

incSteps()

void QwtCounter::setMaxValue

(

double

value

)

Set the maximum value of the range

Parameters:

value

Maximum value

See also:

setMinValue(), maxVal()

void QwtCounter::setMinValue

(

double

value

)

Set the minimum value of the range

Parameters:

value

Minimum value

See also:

setMaxValue(), minValue()

void QwtCounter::setNumButtons

(

int

numButtons

)

Specify the number of buttons on each side of the label.

Parameters:

numButtons

Number of buttons

void QwtDoubleRange::setPeriodic

(

bool

tf

)

[inherited]

Make the range periodic.

When the range is periodic, the value will be set to a point inside the interval such that

point = value + n * width 

if the user tries to set a new value which is outside the range. If the range is nonperiodic (the default), values outside the range will be clipped.

Parameters:

tf	true for a periodic range

void QwtDoubleRange::setRange	(	double	vmin,
		double	vmax,
		double	vstep = 0.0,
		int	pageSize = 1
	)		[inherited]

Specify range and step size.

Parameters:

vmin	lower boundary of the interval
vmax	higher boundary of the interval
vstep	step width
pageSize	page size in steps

Warning:

• A change of the range changes the value if it lies outside the new range. The current value will *not* be adjusted to the new step raster.
• vmax < vmin is allowed.
• If the step size is left out or set to zero, it will be set to 1/100 of the interval length.
• If the step size has an absurd value, it will be corrected to a better one.

void QwtCounter::setStep

(

double

stepSize

)

Set the step size

Parameters:

stepSize

Step size

See also:

QwtDoubleRange::setStep()

Reimplemented from QwtDoubleRange.

void QwtCounter::setStepButton1

(

int

nSteps

)

Set the number of increment steps for button 1

Parameters:

nSteps

Number of steps

void QwtCounter::setStepButton2

(

int

nSteps

)

Set the number of increment steps for button 2

Parameters:

nSteps

Number of steps

void QwtCounter::setStepButton3

(

int

nSteps

)

Set the number of increment steps for button 3

Parameters:

nSteps

Number of steps

void QwtDoubleRange::setValid

(

bool

isValid

)

[inherited]

Set the value to be valid/invalid.

Reimplemented in QwtAbstractSlider.

void QwtCounter::setValue

(

double

value

)

[virtual]

Set a new value.

Calls QwtDoubleRange::setValue and does all visual updates.

Parameters:

value

New value

See also:

QwtDoubleRange::setValue()

Reimplemented from QwtDoubleRange.

QSize QwtCounter::sizeHint

(

)

const [virtual]

A size hint.

double QwtCounter::step

(

)

const

returns the step size

Reimplemented from QwtDoubleRange.

int QwtCounter::stepButton1

(

)

const

returns the number of increment steps for button 1

int QwtCounter::stepButton2

(

)

const

returns the number of increment steps for button 2

int QwtCounter::stepButton3

(

)

const

returns the number of increment steps for button 3

void QwtDoubleRange::stepChange

(

)

[protected, virtual, inherited]

Notify a change of the step size.

This virtual function is called whenever the step size changes. The default implementation does nothing.

double QwtCounter::value

(

)

const [virtual]

Returns:

Current value

Reimplemented from QwtDoubleRange.

void QwtCounter::valueChanged

(

double

value

)

[signal]

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

Parameters:

value

The new value

void QwtCounter::wheelEvent

(

QWheelEvent *

event

)

[protected, virtual]

Handle wheel events

Parameters:

event

Wheel event