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QwtAbstractSlider(3) Qwt User's Guide QwtAbstractSlider(3)

QwtAbstractSlider -

#include <qwt_abstract_slider.h>

Inherits QwtDoubleRange.

Inherited by QwtDial, QwtKnob, QwtSlider, and QwtWheel.


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


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


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


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


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

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.

Scroll mode

See also:

getScrollMode()

Constructor. Parameters:

orientation Orientation
parent Parent widget

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

value Value

See also:

setValue(), incValue()

Reimplemented from QwtDoubleRange.

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:

Scrolling switched off. Don't change the value.
Change the value while the user keeps the button pressed and moves the mouse.
Automatic scrolling. Increment the value in the specified direction as long as the user keeps the button pressed.
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.

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.

Increment the value by a specified number of steps. Parameters:

steps number of steps

See also:

setValue()

Reimplemented from QwtDoubleRange.

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

Returns:

true if read only

See also:

setReadOnly()

See also:

QwtDblRange::isValid()

Reimplemented from QwtDoubleRange.

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 QwtDial, and QwtCompass.

Returns:

mass

See also:

setMass()

Reimplemented in QwtWheel.

Mouse Move Event handler

Parameters:

e Mouse event

Mouse press event handler

Parameters:

e Mouse event

Mouse Release Event handler

Parameters:

e Mouse event

Returns:

Orientation

See also:

setOrientation()

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.

Set the orientation. Parameters:

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

Reimplemented in QwtSlider, and QwtWheel.

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

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()

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.

Specify the update interval for automatic scrolling. Parameters:

t update interval in milliseconds

See also:

getScrollMode()

Parameters:

valid true/false

See also:

QwtDblRange::isValid()

Reimplemented from QwtDoubleRange.

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.

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

Parameters:

value new value

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

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

Qt timer event

Parameters:

e Timer event

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.

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

Wheel Event handler

Parameters:

e Whell event

Generated automatically by Doxygen for Qwt User's Guide from the source code.

Tue Nov 20 2012 Version 5.2.3