QScrollBar - Vertical or horizontal scroll bar

       #include <qscrollbar.h>

       Inherits QRangeControl and QWidget.

   Public Members
       QScrollBar ( QWidget * parent, const char * name=0 )
       QScrollBar ( Orientation, QWidget * parent, const char *
           name=0 )
       QScrollBar ( int minValue, int maxValue, int LineStep, int
           PageStep, int value, Orientation, QWidget * parent,
           const char * name=0 )
       virtual void setOrientation ( Orientation )
       Orientation orientation () const
       virtual void setTracking ( bool enable )
       bool tracking () const
       bool draggingSlider () const
       virtual void setPalette ( const QPalette & )
       void setMinValue ( int )
       void setMaxValue ( int )
       void setLineStep ( int )
       void setPageStep ( int )

   Signals
       void valueChanged ( int value )
       void sliderPressed ()
       void sliderMoved ( int value )
       void sliderReleased ()
       void nextLine ()
       void prevLine ()
       void nextPage ()
       void prevPage ()

   Protected Members
       virtual void valueChange () (internal)
       virtual void stepChange () (internal)
       virtual void rangeChange () (internal)
       int sliderStart () const
       QRect sliderRect () const

   Properties
       Type          Name             READ             WRITE            Options
       -------------------------------------------------------------------------
       int           minValue         minValue         setMinValue
       int           maxValue         maxValue         setMaxValue
       int           lineStep         lineStep         setLineStep
       int           pageStep         pageStep         setPageStep
       int           value            value            setValue
       bool          tracking         tracking         setTracking
       bool          draggingSlider   draggingSlider



DESCRIPTION

       The QScrollBar widget provides a vertical or horizontal
       scroll bar.

       A scroll bar allows the user to control a value within a
       program-definable range, and to give the user visible
       indication of the current value of a range control.

       Scroll bars include four separate controls:

       The line-up and line-down controls are little button with
              which the user can move one line up or down. The
              meaning of "line" is configurable. In editors and
              list boxes it means one line of text, while an
              image viewer it might mean 20 pixels.

       The slider is the handle that indicates the current value
              of the scroll bar, and which the user can drag to
              change the value. This part of the scroll bar is
              sometimes called the "thumb".

       The page-up/down control is the area on which the slider
              slides (the scroll bar's background). Clicking here
              moves the scroll bar towards the click. The meaning
              of page is also configurable - in editors and list
              boxes it means as many lines as there is space for
              in the widget.

       QScrollBar has not much of an API of its own; it mostly
       relies on QRangeControl. The most useful functions are
       setValue() to set the scroll bar directly to some value;
       addPage(), addLine(), subtractPage() and subtractLine() to
       simulate the effects of clicking (useful for accelerator
       keys; setSteps() to define the values of pageStep() and
       lineStep(); and setRange() to set the minValue() and
       maxValue() of the scroll bar. QScrollBar has a convenience
       constructor with which you can set most of these
       properties.

       Some GUI styles, for example the provided Windows and
       Motif styles, also use the pageStep() value to calculate
       the size of the slider.

       In addition to the access functions from QRangeControl,
       QScrollBar has a comprehensive set of signals:

       valueChanged() - emitted when the scroll bar's value has
              changed. The tracking() determines whether this
              signal is emitted during interaction.

              slider

       sliderMoved() - emitted when the user drags the slider

       sliderReleased() - emitted when the user releases the
              slider

       nextLine() - emitted when the scroll bar has moved one
              line down/rightwards. Line is defined in
              QRangeControl.

       prevLine() - emitted when the scroll bar has moved one
              line up/leftwards.

       nextPage() - emitted when the scroll bar has moved one
              page down/rightwards.

       prevPage() - emitted when the scroll bar has moved one
              page up/leftwards.

       QScrollBar only offers integer ranges. Note that while
       QScrollBar handles very large numbers, scroll bars on
       today's screens cannot usefully control ranges above about
       100,000 pixels. Beyond that, it becomes difficult for the
       user to control the scroll bar using either keyboard or
       mouse.

       A scroll bar can be controlled by the keyboard, but it has
       a default focusPolicy() of NoFocus. Use setFocusPolicy()
       to enable keyboard focus. See keyPressEvent() for a list
       of key bindings.

       If you need to add scrollbars to an interface, consider
       using the QScrollView class which encapsulates the common
       uses for scrollbars.

                            [Image Omitted]

                            [Image Omitted]

       See also QSlider, QSpinBox, QScrollView and GUI Design
       Handbook: Scroll Bar


MEMBER FUNCTION DOCUMENTATION


QScrollBar::QScrollBar ( Orientation orientation, QWidget *

       parent, const char * name=0 )
       Constructs a scroll bar.

       The orientation must be QScrollBar::Vertical or
       QScrollBar::Horizontal.

       The parent and name arguments are sent to the QWidget



QScrollBar::QScrollBar ( QWidget * parent, const char * name=0 )

       Constructs a vertical scroll bar.

       The parent and name arguments are sent to the QWidget
       constructor.


QScrollBar::QScrollBar ( int minValue, int maxValue, int

       lineStep, int pageStep, int value, Orientation
       orientation, QWidget * parent, const char * name=0 )
       Constructs a scroll bar.

       Arguments:

       minValue is the minimum scroll bar value.

       maxValue is the maximum scroll bar value.

       lineStep is the line step value.

       pageStep is the page step value. It is also used to
              calculate the size of the slider.

       value is the initial value.

       orientation must be QScrollBar::Vertical or
              QScrollBar::Horizontal. The parent and name
              arguments are sent to the QWidget constructor.


bool QScrollBar::draggingSlider () const

       Returns TRUE if the user has clicked the mouse on the
       slider and is currently dragging it, or FALSE if not.


void QScrollBar::keyPressEvent ( QKeyEvent * e ) [virtual

       protected]
       Reimplemented for internal reasons; the API is not
       affected.

       Reimplemented from QWidget.


int QScrollBar::lineStep () const

       Reimplemented for internal reasons; the API is not
       affected.


int QScrollBar::maxValue () const

       Reimplemented for internal reasons; the API is not
       affected.


int QScrollBar::minValue () const

       Reimplemented for internal reasons; the API is not
       affected.

       protected]
       Reimplemented for internal reasons; the API is not
       affected.

       Reimplemented from QWidget.


void QScrollBar::mousePressEvent ( QMouseEvent * e ) [virtual

       protected]
       Reimplemented for internal reasons; the API is not
       affected.

       Reimplemented from QWidget.


void QScrollBar::mouseReleaseEvent ( QMouseEvent * e ) [virtual

       protected]
       Reimplemented for internal reasons; the API is not
       affected.

       Reimplemented from QWidget.


void QScrollBar::nextLine () [signal]

       This signal is emitted when the scroll bar scrolls one
       line down/right.


void QScrollBar::nextPage () [signal]

       This signal is emitted when the scroll bar scrolls one
       page down/right.


Orientation QScrollBar::orientation () const

       Returns the orientation of the scroll bar;
       QScrollBar::Vertical or QScrollBar::Horizontal.

       See also setOrientation().


int QScrollBar::pageStep () const

       Reimplemented for internal reasons; the API is not
       affected.


void QScrollBar::paintEvent ( QPaintEvent * ) [virtual protected]

       Reimplemented for internal reasons; the API is not
       affected.

       Reimplemented from QWidget.


void QScrollBar::prevLine () [signal]

       This signal is emitted when the scroll bar scrolls one
       line up/left.


void QScrollBar::prevPage () [signal]

       This signal is emitted when the scroll bar scrolls one
       page up/left.

       protected]
       Reimplemented for internal reasons; the API is not
       affected.

       Reimplemented from QWidget.


void QScrollBar::setLineStep ( int i )

       Sets the line step to i.

       Calls the virtual stepChange() function if the new line
       step is different from the previous setting.

       See also lineStep(), QRangeControl::setSteps(),
       setPageStep() and setRange().


void QScrollBar::setMaxValue ( int i )

       A convenience function which just calls setRange(
       minValue(), i )

       See also setRange().


void QScrollBar::setMinValue ( int i )

       A convenience function which just calls setRange( i,
       maxValue() )

       See also setRange().


void QScrollBar::setOrientation ( Orientation orientation )

       [virtual]
       Sets the scroll bar orientation. The orientation must be
       QScrollBar::Vertical or QScrollBar::Horizontal.

       See also orientation().


void QScrollBar::setPageStep ( int i )

       Sets the page step to i.

       Calls the virtual stepChange() function if the new page
       step is different from the previous setting.

       See also pageStep(), QRangeControl::setSteps(),
       setLineStep() and setRange().


void QScrollBar::setPalette ( const QPalette & p ) [virtual]

       Reimplements the virtual function QWidget::setPalette().

       Sets the background color to the mid color for Motif style
       scroll bars.


void QScrollBar::setTracking ( bool enable ) [virtual]

       Enables scroll bar tracking if enable is TRUE, or disables
       tracking if enable is FALSE.

       the valueChanged() signal while the slider is being
       dragged. If tracking is disabled, the scroll bar emits the
       valueChanged() signal only when the user releases the
       mouse button after moving the slider.

       See also tracking().


void QScrollBar::setValue ( int i )

       Reimplemented for internal reasons; the API is not
       affected.


QSize QScrollBar::sizeHint () const [virtual]

       Reimplemented for internal reasons; the API is not
       affected.

       Reimplemented from QWidget.


QSizePolicy QScrollBar::sizePolicy () const [virtual]

       Reimplemented for internal reasons; the API is not
       affected.

       Reimplemented from QWidget.


void QScrollBar::sliderMoved ( int value ) [signal]

       This signal is emitted when the slider is moved by the
       user, with the new scroll bar value as an argument.

       This signal is emitted even when tracking is turned off.

       See also tracking(), valueChanged(), nextLine(),
       prevLine(), nextPage() and prevPage().


void QScrollBar::sliderPressed () [signal]

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


QRect QScrollBar::sliderRect () const [protected]

       Returns the scroll bar slider rectangle.

       See also sliderStart().


void QScrollBar::sliderReleased () [signal]

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


int QScrollBar::sliderStart () const [protected]

       Returns the pixel position where the scroll bar slider
       starts.

       It is equivalent to sliderRect().y() for vertical scroll
       bars or sliderRect().x() for horizontal scroll bars.

       Reimplemented for internal reasons; the API is not
       affected.

       Reimplemented from QWidget.


bool QScrollBar::tracking () const

       Returns TRUE if tracking is enabled, or FALSE if tracking
       is disabled.

       Tracking is initially enabled.

       See also setTracking().


int QScrollBar::value () const

       Reimplemented for internal reasons; the API is not
       affected.


void QScrollBar::valueChanged ( int value ) [signal]

       This signal is emitted when the scroll bar value has
       changed, with the new scroll bar value as an argument.


void QScrollBar::wheelEvent ( QWheelEvent * e ) [virtual

       protected]
       Reimplemented for internal reasons; the API is not
       affected.

       Reimplemented from QWidget.


void QScrollBar::rangeChange () [virtual protected]

       For internal use only.

       Reimplemented from QRangeControl.


void QScrollBar::stepChange () [virtual protected]

       For internal use only.

       Reimplemented from QRangeControl.


void QScrollBar::valueChange () [virtual protected]

       For internal use only.

       Reimplemented from QRangeControl.


SEE ALSO

       http://doc.trolltech.com/qscrollbar.html
       http://www.trolltech.com/faq/tech.html


COPYRIGHT

       Copyright 1992-2001 Trolltech AS,
       http://www.trolltech.com.  See the license file included
       in the distribution for a complete license statement.

       Generated automatically from the source code.


BUGS

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       http://doc.trolltech.com/bughowto.html.  Good bug reports
       make our job much simpler. Thank you.

       In case of content or formattting problems with this
       manual page, please report them to qt-bugs@trolltech.com.
       Please include the name of the manual page
       (qscrollbar.3qt) and the Qt version (2.3.1).


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