qdial.3qt

Trolltech公司发布的基于C++图形开发环境

'\" t
.TH QDial 3qt "24 January 2005" "Trolltech AS" \" -*- nroff -*-
.\" Copyright 1992-2001 Trolltech AS.  All rights reserved.  See the
.\" license file included in the distribution for a complete license
.\" statement.
.\"
.ad l
.nh
.SH NAME
QDial \- Rounded rangecontrol (like a speedometer or potentiometer)
.br
.PP
\fC#include <qdial.h>\fR
.PP
Inherits QRangeControl and QWidget.
.PP
.SS "Public Members"
.in +1c
.ti -1c
.BI "\fBQDial\fR ( QWidget * " "parent" "=0, const char * " "name" "=0 ) "
.br
.ti -1c
.BI "\fBQDial\fR ( int " "minValue" ", int " "maxValue" ", int " "pageStep" ", int " "value" ", QWidget * " "parent" "=0, const char * " "name" "=0 ) "
.br
.ti -1c
.BI "\fB~QDial\fR () "
.br
.ti -1c
.BI "bool \fBtracking\fR () const"
.br
.ti -1c
.BI "bool \fBwrapping\fR () const"
.br
.ti -1c
.BI "int \fBnotchSize\fR () const"
.br
.ti -1c
.BI "virtual void \fBsetNotchTarget\fR ( double ) "
.br
.ti -1c
.BI "double \fBnotchTarget\fR () const"
.br
.ti -1c
.BI "bool \fBnotchesVisible\fR () const"
.br
.ti -1c
.BI "void \fBsetMinValue\fR ( int ) "
.br
.ti -1c
.BI "void \fBsetMaxValue\fR ( int ) "
.br
.ti -1c
.BI "void \fBsetLineStep\fR ( int ) "
.br
.ti -1c
.BI "void \fBsetPageStep\fR ( int ) "
.br
.in -1c
.SS "Public Slots"
.in +1c
.ti -1c
.BI "virtual void \fBsetValue\fR ( int ) "
.br
.ti -1c
.BI "void \fBaddLine\fR () "
.br
.ti -1c
.BI "void \fBsubtractLine\fR () "
.br
.ti -1c
.BI "void \fBaddPage\fR () "
.br
.ti -1c
.BI "void \fBsubtractPage\fR () "
.br
.ti -1c
.BI "virtual void \fBsetNotchesVisible\fR ( bool b ) "
.br
.ti -1c
.BI "virtual void \fBsetWrapping\fR ( bool on ) "
.br
.ti -1c
.BI "virtual void \fBsetTracking\fR ( bool enable ) "
.br
.in -1c
.SS "Signals"
.in +1c
.ti -1c
.BI "void \fBvalueChanged\fR ( int value ) "
.br
.ti -1c
.BI "void \fBdialPressed\fR () "
.br
.ti -1c
.BI "void \fBdialMoved\fR ( int value ) "
.br
.ti -1c
.BI "void \fBdialReleased\fR () "
.br
.in -1c
.SS "Protected Members"
.in +1c
.ti -1c
.BI "virtual void \fBvalueChange\fR () "
.br
.ti -1c
.BI "virtual void \fBrangeChange\fR () "
.br
.ti -1c
.BI "virtual void \fBrepaintScreen\fR ( const QRect * " "cr" " = 0 ) "
.br
.in -1c
.SS "Properties"
.nf
.TS
l l l l l
- - - - -
l l l l l.
Type	Name	READ	WRITE	Options
bool	tracking	tracking	setTracking
bool	wrapping	wrapping	setWrapping
int	notchSize	notchSize
double	notchTarget	notchTarget	setNotchTarget
bool	notchesVisible	notchesVisible	setNotchesVisible
int	minValue	minValue	setMinValue
int	maxValue	maxValue	setMaxValue
int	lineStep	lineStep	setLineStep
int	pageStep	pageStep	setPageStep
int	value	value	setValue
.TE
.fi

.SH DESCRIPTION
The QDial class provides a rounded rangecontrol (like a speedometer or potentiometer).
.PP
Q dial is used when the user needs to control a value within a program-definable range, and the range either wraps around (typically, 0-359 degrees) or the dialog layout needs a square widget.
.PP
Both API- and UI-wise, the dial is very like a slider. Indeed, when wrapping() is FALSE (the default) there is no hard difference between a slider and a dial. They have the same signals, slots and member functions, all of which do the same things. Which one to use depends only on your taste and on the application.
.PP
The dial initially emits valueChanged() signals continuously while the slider is being moved; you can make it emit the signal less often by calling setTracking( FALSE ). dialMoved() is emitted continuously even when tracking() is FALSE.
.PP
The slider also emits dialPressed() and dialReleased() signals when the mouse button is pressed and released. But note that the dial's value can change without these signals being emitted; the keyboard and wheel can be used to change the value.
.PP
Unlike the slider, QDial attempts to draw a "nice" number of notches rather than one per lineStep(). If possible, that number \fIis\fR lineStep(), but if there aren't enough pixels to draw every, QDial will draw every second, third or something. notchSize() returns the number of units per notch, hopefully a multiple of lineStep(); setNotchTarget() sets the target distance between neighbouring notches in pixels. The default is 3.75 pixels.
.PP
Like the slider, the dial makes the QRangeControl functions setValue(), addLine(), substractLine(), addPage() and subtractPage() available as slots.
.PP
The dial's keyboard interface is fairly simple: The left/up and right/down arrow keys move by lineStep(), page up and page down by pageStep() and Home and End to minValue() and maxValue().
.PP
.ce 1
.B "[Image Omitted]"
.PP

.ce 1
.B "[Image Omitted]"
.PP
See also QScrollBar, QSpinBox and GUI Design Handbook: Slider
.SH MEMBER FUNCTION DOCUMENTATION
.SH "QDial::QDial ( QWidget * parent=0, const char * name=0 )"
Constructs a dial with the default range of QRangeControl.
.SH "QDial::QDial ( int minValue, int maxValue, int pageStep, int value, QWidget * parent=0, const char * name=0 )"
Constructs a dial whose value can never be smaller than \fIminValue\fR or greater than \fImaxValue,\fR whose line step size is \fIlineStep\fR and page step size is \fIpageStep,\fR and whose value is initially \fIvalue.\fR
.PP
\fIvalue\fR is forced to be within the legal range.
.SH "QDial::~QDial ()"
Destructs the dial.
.SH "void QDial::addLine () \fC[slot]\fR"
Moves the dial one lineStep() upwards.
.SH "void QDial::addPage () \fC[slot]\fR"
Moves the dial one pageStep() upwards.
.SH "void QDial::dialMoved ( int value ) \fC[signal]\fR"
This signal is emitted whenever the dial value changes. The frequency of this signal is \fInot\fR influenced by setTracking().
.PP
See also valueChanged(int).
.SH "void QDial::dialPressed () \fC[signal]\fR"
This signal is emitted when the use begins mouse interaction with the dial.
.PP
See also dialReleased().
.SH "void QDial::dialReleased () \fC[signal]\fR"
This signal is emitted when the use ends mouse interaction with the dial.
.PP
See also dialPressed().
.SH "void QDial::focusInEvent ( QFocusEvent * ) \fC[virtual protected]\fR"
Reimplemented for internal reasons; the API is not affected.
.PP
Reimplemented from QWidget.
.SH "void QDial::focusOutEvent ( QFocusEvent * ) \fC[virtual protected]\fR"
Reimplemented for internal reasons; the API is not affected.
.PP
Reimplemented from QWidget.
.SH "void QDial::keyPressEvent ( QKeyEvent * e ) \fC[virtual protected]\fR"
Reimplemented for internal reasons; the API is not affected.
.PP
Reimplemented from QWidget.
.SH "int QDial::lineStep () const"
Reimplemented for internal reasons; the API is not affected.
.SH "int QDial::maxValue () const"
Reimplemented for internal reasons; the API is not affected.
.SH "int QDial::minValue () const"
Reimplemented for internal reasons; the API is not affected.
.SH "QSize QDial::minimumSizeHint () const \fC[virtual]\fR"
Reimplemented for internal reasons; the API is not affected.
.PP
Reimplemented from QWidget.
.SH "void QDial::mouseMoveEvent ( QMouseEvent * e ) \fC[virtual protected]\fR"
Reimplemented for internal reasons; the API is not affected.
.PP
Reimplemented from QWidget.
.SH "void QDial::mousePressEvent ( QMouseEvent * e ) \fC[virtual protected]\fR"
Reimplemented for internal reasons; the API is not affected.
.PP
Reimplemented from QWidget.
.SH "void QDial::mouseReleaseEvent ( QMouseEvent * e ) \fC[virtual protected]\fR"
Reimplemented for internal reasons; the API is not affected.
.PP
Reimplemented from QWidget.
.SH "int QDial::notchSize () const"
Returns the current notch size. This is in range control units, not pixels, and if possible it is a multiple of lineStep() that results in an on-screen notch size near notchTarget().
.PP
See also notchTarget() and lineStep().
.SH "double QDial::notchTarget () const"
Returns the target size of the notch; this is the number of pixels QDial attempts to put between each little line.
.PP
The actual size differs a bit from the target.
.SH "bool QDial::notchesVisible () const"
Retuns TRUE if notches are shown, else FALSE.
.PP
See also setNotchesVisible().
.SH "int QDial::pageStep () const"
Reimplemented for internal reasons; the API is not affected.
.SH "void QDial::paintEvent ( QPaintEvent * e ) \fC[virtual protected]\fR"
Reimplemented for internal reasons; the API is not affected.
.PP
Reimplemented from QWidget.
.SH "void QDial::rangeChange () \fC[virtual protected]\fR"
Reimplemented to ensure tick-marks are consistent with the new range.
.PP
Reimplemented from QRangeControl.
.SH "void QDial::repaintScreen ( const QRect * cr = 0 ) \fC[virtual protected]\fR"
Paints the dial.
.SH "void QDial::resizeEvent ( QResizeEvent * e ) \fC[virtual protected]\fR"
Reimplemented for internal reasons; the API is not affected.
.PP
Reimplemented from QWidget.
.SH "void QDial::setLineStep ( int i )"
Sets the line step to \fIi.\fR
.PP
Calls the virtual stepChange() function if the new line step is different from the previous setting.
.PP
See also lineStep(), QRangeControl::setSteps(), setPageStep() and setRange().
.SH "void QDial::setMaxValue ( int i )"
A convenience function which just calls setRange( minValue(), i )
.PP
See also setRange().
.SH "void QDial::setMinValue ( int i )"
A convenience function which just calls setRange( i, maxValue() )
.PP
See also setRange().
.SH "void QDial::setNotchTarget ( double target ) \fC[virtual]\fR"
Sets the dial to use a notch size as close to \fItarget\fR pixels as possible. QDial will find a suitable number close to this, based on the dial's on-screen size, range and lineStep().
.PP
See also notchTarget() and notchSize().
.SH "void QDial::setNotchesVisible ( bool b ) \fC[virtual slot]\fR"
Enables or disables showing of notches. If \fIb\fR is TRUE, the notches are shown, else not.
.SH "void QDial::setPageStep ( int i )"
Sets the page step to \fIi.\fR
.PP
Calls the virtual stepChange() function if the new page step is different from the previous setting.
.PP
See also pageStep(), QRangeControl::setSteps(), setLineStep() and setRange().
.SH "void QDial::setTracking ( bool enable ) \fC[virtual slot]\fR"
If \fIenable\fR is TRUE, tracking is enabled. This means that the arrow can be moved using the mouse. Else this is not possible.
.SH "void QDial::setValue ( int newValue ) \fC[virtual slot]\fR"
Makes QRangeControl::setValue() available as a slot.
.SH "void QDial::setWrapping ( bool enable ) \fC[virtual slot]\fR"
If \fIenable\fR is TRUE, wrapping is enabled. This means that the arrow can be turned around 360