Provided by: libqwt-doc_6.1.4-2_all 
NAME
QwtAbstractSlider - An abstract base class for slider widgets with a scale.
SYNOPSIS
#include <qwt_abstract_slider.h>
Inherits QwtAbstractScale.
Inherited by QwtDial, QwtKnob, and QwtSlider.
Public Slots
void setValue (double value)
Signals
void valueChanged (double value)
Notify a change of value.
void sliderPressed ()
void sliderReleased ()
void sliderMoved (double value)
Public Member Functions
QwtAbstractSlider (QWidget *parent=NULL)
Constructor.
virtual ~QwtAbstractSlider ()
Destructor.
void setValid (bool)
bool isValid () const
double value () const
Returns the current value.
void setWrapping (bool)
bool wrapping () const
void setTotalSteps (uint)
Set the number of steps.
uint totalSteps () const
void setSingleSteps (uint)
Set the number of steps for a single increment.
uint singleSteps () const
void setPageSteps (uint)
Set the number of steps for a page increment.
uint pageSteps () const
void setStepAlignment (bool)
Enable step alignment.
bool stepAlignment () const
void setTracking (bool)
Enables or disables tracking.
bool isTracking () const
void setReadOnly (bool)
bool isReadOnly () const
void setInvertedControls (bool)
bool invertedControls () const
Protected Member Functions
virtual void mousePressEvent (QMouseEvent *)
virtual void mouseReleaseEvent (QMouseEvent *)
virtual void mouseMoveEvent (QMouseEvent *)
virtual void keyPressEvent (QKeyEvent *)
virtual void wheelEvent (QWheelEvent *)
virtual bool isScrollPosition (const QPoint &pos) const =0
Determine what to do when the user presses a mouse button.
virtual double scrolledTo (const QPoint &pos) const =0
Determine the value for a new position of the movable part of the slider.
void incrementValue (int stepCount)
virtual void scaleChange ()
virtual void sliderChange ()
Calling update()
double incrementedValue (double value, int stepCount) const
Detailed Description
An abstract base class for slider widgets with a scale.
A slider widget displays a value according to a scale. The class is designed as a common
super class for widgets like QwtKnob, QwtDial and QwtSlider.
When the slider is nor readOnly() its value can be modified by keyboard, mouse and wheel
inputs.
The range of the slider is divided into a number of steps from which the value increments
according to user inputs depend. Only for linear scales the number of steps correspond
with a fixed step size.
Constructor & Destructor Documentation
QwtAbstractSlider::QwtAbstractSlider (QWidget * parent = NULL) [explicit]
Constructor. The scale is initialized to [0.0, 100.0], the number of steps is set to 100
with 1 and 10 and single an page step sizes. Step alignment is enabled.
The initial value is invalid.
Parameters:
parent Parent widget
Member Function Documentation
double QwtAbstractSlider::incrementedValue (double value, int stepCount) const [protected]
Increment a value
Parameters:
value Value
stepCount Number of steps
Returns:
Incremented value
void QwtAbstractSlider::incrementValue (int stepCount) [protected]
Increment the slider
The step size depends on the number of totalSteps()
Parameters:
stepCount Number of steps
See also:
setTotalSteps(), incrementedValue()
bool QwtAbstractSlider::invertedControls () const
Returns:
True, when the controls are inverted
See also:
setInvertedControls()
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()
virtual bool QwtAbstractSlider::isScrollPosition (const QPoint & pos) const [protected],
[pure virtual]
Determine what to do when the user presses a mouse button.
Parameters:
pos Mouse position
Return values:
True,when pos is a valid scroll position
See also:
scrolledTo()
Implemented in QwtKnob, QwtDial, and QwtSlider.
bool QwtAbstractSlider::isTracking () const
Returns:
True, when tracking has been enabled
See also:
setTracking()
bool QwtAbstractSlider::isValid () const
Returns:
True, when the value is invalid
void QwtAbstractSlider::keyPressEvent (QKeyEvent * event) [protected], [virtual]
Handles key events
QwtAbstractSlider handles the following keys:
• Qt::Key_Left
Add/Subtract singleSteps() in direction to lowerBound();
• Qt::Key_Right
Add/Subtract singleSteps() in direction to upperBound();
• Qt::Key_Down
Subtract singleSteps(), when invertedControls() is false
• Qt::Key_Up
Add singleSteps(), when invertedControls() is false
• Qt::Key_PageDown
Subtract pageSteps(), when invertedControls() is false
• Qt::Key_PageUp
Add pageSteps(), when invertedControls() is false
• Qt::Key_Home
Set the value to the minimum()
• Qt::Key_End
Set the value to the maximum()
Parameters:
event Key event
See also:
isReadOnly()
Reimplemented in QwtCompass.
void QwtAbstractSlider::mouseMoveEvent (QMouseEvent * event) [protected], [virtual]
Mouse Move Event handler
Parameters:
event Mouse event
void QwtAbstractSlider::mousePressEvent (QMouseEvent * event) [protected], [virtual]
Mouse press event handler
Parameters:
event Mouse event
Reimplemented in QwtSlider.
void QwtAbstractSlider::mouseReleaseEvent (QMouseEvent * event) [protected], [virtual]
Mouse Release Event handler
Parameters:
event Mouse event
Reimplemented in QwtSlider.
uint QwtAbstractSlider::pageSteps () const
Returns:
Number of steps
See also:
setPageSteps(), totalSteps(), singleSteps()
void QwtAbstractSlider::scaleChange () [protected], [virtual]
Update the slider according to modifications of the scale
Reimplemented from QwtAbstractScale.
Reimplemented in QwtDial, and QwtSlider.
virtual double QwtAbstractSlider::scrolledTo (const QPoint & pos) const [protected], [pure
virtual]
Determine the value for a new position of the movable part of the slider.
Parameters:
pos Mouse position
Returns:
Value for the mouse position
See also:
isScrollPosition()
Implemented in QwtKnob, QwtDial, and QwtSlider.
void QwtAbstractSlider::setInvertedControls (bool on)
Invert wheel and key events
Usually scrolling the mouse wheel 'up' and using keys like page up will increase the
slider's value towards its maximum. When invertedControls() is enabled the value is
scrolled towards its minimum.
Inverting the controls might be f.e. useful for a vertical slider with an inverted scale (
decreasing from top to bottom ).
Parameters:
on Invert controls, when true
See also:
invertedControls(), keyEvent(), wheelEvent()
void QwtAbstractSlider::setPageSteps (uint stepCount)
Set the number of steps for a page increment. The range of the slider is divided into a
number of steps from which the value increments according to user inputs depend.
Parameters:
stepCount Number of steps
See also:
pageSteps(), setTotalSteps(), setSingleSteps()
void QwtAbstractSlider::setReadOnly (bool on)
En/Disable read only mode
In read only mode the slider can't be controlled by mouse or keyboard.
Parameters:
on Enables in case of true
See also:
isReadOnly()
Warning:
The focus policy is set to Qt::StrongFocus or Qt::NoFocus
void QwtAbstractSlider::setSingleSteps (uint stepCount)
Set the number of steps for a single increment. The range of the slider is divided into a
number of steps from which the value increments according to user inputs depend.
Parameters:
stepCount Number of steps
See also:
singleSteps(), setTotalSteps(), setPageSteps()
void QwtAbstractSlider::setStepAlignment (bool on)
Enable step alignment. When step alignment is enabled values resulting from slider
movements are aligned to the step size.
Parameters:
on Enable step alignment when true
See also:
stepAlignment()
void QwtAbstractSlider::setTotalSteps (uint stepCount)
Set the number of steps. The range of the slider is divided into a number of steps from
which the value increments according to user inputs depend.
The default setting is 100.
Parameters:
stepCount Number of steps
See also:
totalSteps(), setSingleSteps(), setPageSteps()
void QwtAbstractSlider::setTracking (bool on)
Enables or disables tracking. If tracking is enabled, the slider emits the valueChanged()
signal while the movable part of the slider is being dragged. If tracking is disabled, the
slider emits the valueChanged() signal only when the user releases the slider.
Tracking is enabled by default.
Parameters:
on true (enable) or false (disable) tracking.
See also:
isTracking(), sliderMoved()
void QwtAbstractSlider::setValid (bool on)
Set the value to be valid/invalid
Parameters:
on When true, the value is invalidated
See also:
setValue()
void QwtAbstractSlider::setValue (double value) [slot]
Set the slider to the specified value
Parameters:
value New value
See also:
setValid(), sliderChange(), valueChanged()
void QwtAbstractSlider::setWrapping (bool on)
If wrapping is true stepping up from upperBound() value will take you to the minimum()
value and vice versa.
Parameters:
on En/Disable wrapping
See also:
wrapping()
uint QwtAbstractSlider::singleSteps () const
Returns:
Number of steps
See also:
setSingleSteps(), totalSteps(), pageSteps()
void QwtAbstractSlider::sliderMoved (double value) [signal]
This signal is emitted when the user moves the slider with the mouse.
Parameters:
value New value
See also:
valueChanged()
void QwtAbstractSlider::sliderPressed () [signal]
This signal is emitted when the user presses the movable part of the slider.
void QwtAbstractSlider::sliderReleased () [signal]
This signal is emitted when the user releases the movable part of the slider.
bool QwtAbstractSlider::stepAlignment () const
Returns:
True, when step alignment is enabled
See also:
setStepAlignment()
uint QwtAbstractSlider::totalSteps () const
Returns:
Number of steps
See also:
setTotalSteps(), singleSteps(), pageSteps()
void QwtAbstractSlider::valueChanged (double value) [signal]
Notify a change of value. When tracking is enabled (default setting), this signal will be
emitted every time the value changes.
Parameters:
value New value
See also:
setTracking(), sliderMoved()
void QwtAbstractSlider::wheelEvent (QWheelEvent * event) [protected], [virtual]
Wheel Event handler
In/decreases the value by s number of steps. The direction depends on the
invertedControls() property.
When the control or shift modifier is pressed the wheel delta ( divided by 120 ) is mapped
to an increment according to pageSteps(). Otherwise it is mapped to singleSteps().
Parameters:
event Wheel event
Reimplemented in QwtDial.
bool QwtAbstractSlider::wrapping () const
Returns:
True, when wrapping is set
See also:
setWrapping()
Author
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