Qwt User's Guide: QwtAbstractSlider Class Reference

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QwtAbstractSlider Class Reference

An abstract base class for slider widgets. More...

#include <qwt_abstract_slider.h>

Inheritance diagram for QwtAbstractSlider:
[legend]

List of all members.

Public Types

enum  ScrollMode {
  ScrNone,
  ScrMouse,
  ScrTimer,
  ScrDirect,
  ScrPage
}

Public Slots

virtual void setValue (double val)
virtual void fitValue (double val)
virtual void incValue (int steps)
virtual void setReadOnly (bool)

Signals

void valueChanged (double value)
void sliderPressed ()
void sliderReleased ()
void sliderMoved (double value)

Public Member Functions

 QwtAbstractSlider (Qt::Orientation, QWidget *parent=NULL)
virtual ~QwtAbstractSlider ()
void setUpdateTime (int t)
void stopMoving ()
void setTracking (bool enable)
virtual void setMass (double val)
virtual double mass () const
virtual void setOrientation (Qt::Orientation o)
Qt::Orientation orientation () const
bool isReadOnly () const
bool isValid () const
void setValid (bool valid)

Protected Member Functions

virtual void setPosition (const QPoint &)
virtual void valueChange ()
virtual void timerEvent (QTimerEvent *e)
virtual void mousePressEvent (QMouseEvent *e)
virtual void mouseReleaseEvent (QMouseEvent *e)
virtual void mouseMoveEvent (QMouseEvent *e)
virtual void keyPressEvent (QKeyEvent *e)
virtual void wheelEvent (QWheelEvent *e)
virtual double getValue (const QPoint &p)=0
virtual void getScrollMode (const QPoint &p, int &scrollMode, int &direction)=0
void setMouseOffset (double)
double mouseOffset () const
int scrollMode () const

Detailed Description

An abstract base class for slider widgets.

QwtAbstractSlider is a base class for slider widgets. It handles mouse events and updates the slider's value accordingly. Derived classes only have to implement the getValue() and getScrollMode() members, and should react to a valueChange(), which normally requires repainting.

Member Enumeration Documentation

enum QwtAbstractSlider::ScrollMode

Scroll mode

See also:
getScrollMode()

Constructor & Destructor Documentation

QwtAbstractSlider::QwtAbstractSlider ( Qt::Orientation  orientation,
QWidget *  parent = NULL 
) [explicit]

Constructor.

Parameters:
orientation Orientation
parent Parent widget
QwtAbstractSlider::~QwtAbstractSlider (  )  [virtual]

Destructor.

Member Function Documentation

void QwtAbstractSlider::fitValue ( double  value  )  [virtual, slot]

Set the slider's value to the nearest integer multiple of the step size.

Parameters:
value Value
See also:
setValue(), incValue()

Reimplemented from QwtDoubleRange.

virtual void QwtAbstractSlider::getScrollMode ( const QPoint &  p,
int &  scrollMode,
int &  direction 
) [protected, pure virtual]

Determine what to do when the user presses a mouse button.

This function is abstract and has to be implemented by derived classes. It is called on a mousePress event. The derived class can determine what should happen next in dependence of the position where the mouse was pressed by returning scrolling mode and direction. QwtAbstractSlider knows the following modes:

QwtAbstractSlider::ScrNone
Scrolling switched off. Don't change the value.
QwtAbstractSlider::ScrMouse
Change the value while the user keeps the button pressed and moves the mouse.
QwtAbstractSlider::ScrTimer
Automatic scrolling. Increment the value in the specified direction as long as the user keeps the button pressed.
QwtAbstractSlider::ScrPage
Automatic scrolling. Same as ScrTimer, but increment by page size.
Parameters:
p point where the mouse was pressed
Return values:
scrollMode The scrolling mode
direction direction: 1, 0, or -1.

Implemented in QwtDial, QwtSlider, and QwtWheel.

virtual double QwtAbstractSlider::getValue ( const QPoint &  p  )  [protected, pure virtual]

Determine the value corresponding to a specified poind.

This is an abstract virtual function which is called when the user presses or releases a mouse button or moves the mouse. It has to be implemented by the derived class.

Parameters:
p point

Implemented in QwtDial, QwtSlider, and QwtWheel.

void QwtAbstractSlider::incValue ( int  steps  )  [virtual, slot]

Increment the value by a specified number of steps.

Parameters:
steps number of steps
See also:
setValue()

Reimplemented from QwtDoubleRange.

bool QwtAbstractSlider::isReadOnly (  )  const

In read only mode the slider can't be controlled by mouse or keyboard.

Returns:
true if read only
See also:
setReadOnly()
bool QwtAbstractSlider::isValid (  )  const [inline]
See also:
QwtDblRange::isValid()

Reimplemented from QwtDoubleRange.

void QwtAbstractSlider::keyPressEvent ( QKeyEvent *  e  )  [protected, virtual]

Handles key events

  • Key_Down, KeyLeft
    Decrement by 1
  • Key_Up, Key_Right
    Increment by 1
Parameters:
e Key event
See also:
isReadOnly()

Reimplemented in QwtCompass, and QwtDial.

double QwtAbstractSlider::mass (  )  const [virtual]
Returns:
mass
See also:
setMass()

Reimplemented in QwtWheel.

void QwtAbstractSlider::mouseMoveEvent ( QMouseEvent *  e  )  [protected, virtual]

Mouse Move Event handler

Parameters:
e Mouse event
void QwtAbstractSlider::mousePressEvent ( QMouseEvent *  e  )  [protected, virtual]

Mouse press event handler

Parameters:
e Mouse event
void QwtAbstractSlider::mouseReleaseEvent ( QMouseEvent *  e  )  [protected, virtual]

Mouse Release Event handler

Parameters:
e Mouse event
Qt::Orientation QwtAbstractSlider::orientation (  )  const
Returns:
Orientation
See also:
setOrientation()
void QwtAbstractSlider::setMass ( double  val  )  [virtual]

Set the slider's mass for flywheel effect.

If the slider's mass is greater then 0, it will continue to move after the mouse button has been released. Its speed decreases with time at a rate depending on the slider's mass. A large mass means that it will continue to move for a long time.

Derived widgets may overload this function to make it public.

Parameters:
val New mass in kg
See also:
mass()

Reimplemented in QwtWheel.

void QwtAbstractSlider::setOrientation ( Qt::Orientation  o  )  [virtual]

Set the orientation.

Parameters:
o Orientation. Allowed values are Qt::Horizontal and Qt::Vertical.

Reimplemented in QwtSlider, and QwtWheel.

void QwtAbstractSlider::setPosition ( const QPoint &  p  )  [protected, virtual]

Move the slider to a specified point, adjust the value and emit signals if necessary.

void QwtAbstractSlider::setReadOnly ( bool  readOnly  )  [virtual, slot]

En/Disable read only mode

In read only mode the slider can't be controlled by mouse or keyboard.

Parameters:
readOnly Enables in case of true
See also:
isReadOnly()
void QwtAbstractSlider::setTracking ( bool  enable  ) 

Enables or disables tracking.

If tracking is enabled, the slider emits a valueChanged() signal whenever its value changes (the default behaviour). If tracking is disabled, the value changed() signal will only be emitted if:

  • the user releases the mouse button and the value has changed or
  • at the end of automatic scrolling.

Tracking is enabled by default.

Parameters:
enable true (enable) or false (disable) tracking.
void QwtAbstractSlider::setUpdateTime ( int  t  ) 

Specify the update interval for automatic scrolling.

Parameters:
t update interval in milliseconds
See also:
getScrollMode()
void QwtAbstractSlider::setValid ( bool  valid  )  [inline]
Parameters:
valid true/false
See also:
QwtDblRange::isValid()

Reimplemented from QwtDoubleRange.

void QwtAbstractSlider::setValue ( double  val  )  [virtual, slot]

Move the slider to a specified value.

This function can be used to move the slider to a value which is not an integer multiple of the step size.

Parameters:
val new value
See also:
fitValue()

Reimplemented from QwtDoubleRange.

void QwtAbstractSlider::sliderMoved ( double  value  )  [signal]

This signal is emitted when the user moves the slider with the mouse.

Parameters:
value new value
void QwtAbstractSlider::sliderPressed (  )  [signal]

This signal is emitted when the user presses the movable part of the slider (start ScrMouse Mode).

void QwtAbstractSlider::sliderReleased (  )  [signal]

This signal is emitted when the user releases the movable part of the slider.

void QwtAbstractSlider::stopMoving (  ) 

Stop updating if automatic scrolling is active.

void QwtAbstractSlider::timerEvent ( QTimerEvent *  e  )  [protected, virtual]

Qt timer event

Parameters:
e Timer event
void QwtAbstractSlider::valueChange (  )  [protected, virtual]

Notify change of value

This function can be reimplemented by derived classes in order to keep track of changes, i.e. repaint the widget. The default implementation emits a valueChanged() signal if tracking is enabled.

Reimplemented from QwtDoubleRange.

Reimplemented in QwtDial, QwtSlider, and QwtWheel.

void QwtAbstractSlider::valueChanged ( double  value  )  [signal]

Notify a change of value.

In the default setting (tracking enabled), this signal will be emitted every time the value changes ( see setTracking() ).

Parameters:
value new value
void QwtAbstractSlider::wheelEvent ( QWheelEvent *  e  )  [protected, virtual]

Wheel Event handler

Parameters:
e Whell event
Generated on Wed Sep 2 18:37:23 2009 for Qwt User's Guide by  doxygen 1.6.1
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