QwtAbstractSlider(3) Qwt User's Guide QwtAbstractSlider(3)NAMEQwtAbstractSlider-
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 fitValue (double val)
virtual void incValue (int steps)
virtual void setReadOnly (bool)
virtual void setValue (double val)
Signals
void sliderMoved (double value)
void sliderPressed ()
void sliderReleased ()
void valueChanged (double value)
Public Member Functions
virtual void incPages (int)
bool isReadOnly () const
bool isValid () const
virtual double mass () const
double maxValue () const
double minValue () const
Qt::Orientation orientation () const
int pageSize () const
bool periodic () const
QwtAbstractSlider (Qt::Orientation, QWidget *parent=NULL)
virtual void setMass (double val)
virtual void setOrientation (Qt::Orientation o)
void setPeriodic (bool tf)
void setRange (double vmin, double vmax, double vstep=0.0, int
pagesize=1)
void setStep (double)
void setTracking (bool enable)
void setUpdateTime (int t)
void setValid (bool valid)
double step () const
void stopMoving ()
double value () const
virtual ~QwtAbstractSlider ()
Protected Member Functions
double exactPrevValue () const
double exactValue () const
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)
double prevValue () const
virtual void rangeChange ()
int scrollMode () const
void setMouseOffset (double)
virtual void setPosition (const QPoint &)
virtual void stepChange ()
virtual void timerEvent (QTimerEvent *e)
virtual void valueChange ()
virtual void wheelEvent (QWheelEvent *e)
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::Orientationorientation, QWidget
*parent = NULL) [explicit]
Constructor. Parameters:
orientation Orientation
parent Parent widget
QwtAbstractSlider::~QwtAbstractSlider () [virtual]
Destructor.
Member Function Documentation
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
QwtDoubleRange::fitValue or QwtDoubleRange::incValue have been used
before. This function is intended for internal use in derived classes.
void QwtAbstractSlider::fitValue (doublevalue) [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 QwtDoubleRange::incPages (intnPages) [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.
void QwtAbstractSlider::incValue (intsteps) [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.
double QwtDoubleRange::maxValue () const [inherited]
Returns the value of the second border of the range. maxValue returns
the value which has been specified as the second parameter in
QwtDoubleRange::setRange.
See also:
setRange()
double QwtDoubleRange::minValue () const [inherited]
Returns the value at the first border of the range. minValue returns
the value which has been specified as the first parameter in
setRange().
See also:
setRange()
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()
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 QwtDoubleRange::rangeChange () [protected, virtual, inherited]
Notify a change of the range. This virtual function is called whenever
the range changes. The default implementation does nothing.
Reimplemented in QwtCounter, QwtDial, and QwtSlider.
void QwtAbstractSlider::setMass (doubleval) [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::Orientationo) [virtual]
Set the orientation. Parameters:
o Orientation. Allowed values are Qt::Horizontal and Qt::Vertical.
Reimplemented in QwtSlider, and QwtWheel.
void QwtDoubleRange::setPeriodic (booltf) [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 .fi
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 QwtAbstractSlider::setPosition (const QPoint &p) [protected, virtual]
Move the slider to a specified point, adjust the value and emit signals
if necessary.
void QwtDoubleRange::setRange (doublevmin, doublevmax, doublevstep = 0.0,
intpageSize = 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 QwtAbstractSlider::setReadOnly (boolreadOnly) [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 QwtDoubleRange::setStep (doublevstep) [inherited]
Change the step raster. Parameters:
vstep new step width
Warning:
The value will not be adjusted to the new step raster.
Reimplemented in QwtCounter.
void QwtAbstractSlider::setTracking (boolenable)
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 (intt)
Specify the update interval for automatic scrolling. Parameters:
t update interval in milliseconds
See also:
getScrollMode()
void QwtAbstractSlider::setValid (boolvalid) [inline] Parameters:
valid true/false
See also:
QwtDblRange::isValid()
Reimplemented from QwtDoubleRange.
void QwtAbstractSlider::setValue (doubleval) [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 (doublevalue) [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.
double QwtDoubleRange::step () const [inherited] Returns:
the step size
See also:
setStep(), setRange()
Reimplemented in QwtCounter.
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.
void QwtAbstractSlider::stopMoving ()
Stop updating if automatic scrolling is active.
void QwtAbstractSlider::timerEvent (QTimerEvent *e) [protected, virtual] Qt
timer event
Parameters:
e Timer event
double QwtDoubleRange::value () const [inherited]
Returns the current value.
Reimplemented in QwtCounter.
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 (doublevalue) [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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Version 5.2.2 Mon Aug 1 2011 QwtAbstractSlider(3)
