NAME
QwtAbstractSlider - An abstract base class for slider widgets.
SYNOPSIS
#include <qwt_abstract_slider.h>
Inherits QwtDoubleRange.
Inherited by QwtDial, QwtKnob, QwtSlider, and QwtWheel.
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
Author
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