/****************************************************************************+
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**+
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** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).+
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** All rights reserved.+
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** Contact: Nokia Corporation (qt-info@nokia.com)+
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**+
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** This file is part of the QtGui module of the Qt Toolkit.+
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**+
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** $QT_BEGIN_LICENSE:LGPL$+
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** No Commercial Usage+
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** This file contains pre-release code and may not be distributed.+
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** You may use this file in accordance with the terms and conditions+
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** contained in the Technology Preview License Agreement accompanying+
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** this package.+
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**+
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** GNU Lesser General Public License Usage+
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** Alternatively, this file may be used under the terms of the GNU Lesser+
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** General Public License version 2.1 as published by the Free Software+
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** Foundation and appearing in the file LICENSE.LGPL included in the+
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** packaging of this file.  Please review the following information to+
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** ensure the GNU Lesser General Public License version 2.1 requirements+
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** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.+
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**+
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** In addition, as a special exception, Nokia gives you certain additional+
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** rights.  These rights are described in the Nokia Qt LGPL Exception+
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** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.+
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**+
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** If you have questions regarding the use of this file, please contact+
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** Nokia at qt-info@nokia.com.+
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**+
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**+
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**+
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**+
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**+
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**+
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**+
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**+
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** $QT_END_LICENSE$+
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**+
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****************************************************************************/+
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+
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#include "qdial.h"+
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+
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#ifndef QT_NO_DIAL+
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+
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#include <qapplication.h>+
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#include <qbitmap.h>+
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#include <qcolor.h>+
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#include <qevent.h>+
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#include <qpainter.h>+
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#include <qpolygon.h>+
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#include <qregion.h>+
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#include <qstyle.h>+
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#include <qstylepainter.h>+
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#include <qstyleoption.h>+
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#include <qslider.h>+
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#include <private/qabstractslider_p.h>+
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#include <private/qmath_p.h>+
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#ifndef QT_NO_ACCESSIBILITY+
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#include "qaccessible.h"+
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#endif+
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#include <qmath.h>+
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+
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QT_BEGIN_NAMESPACE+
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+
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class QDialPrivate : public QAbstractSliderPrivate+
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{+
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    Q_DECLARE_PUBLIC(QDial)+
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public:+
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    QDialPrivate()+
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    {+
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        wrapping = false;+
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        tracking = true;+
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        doNotEmit = false;+
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        target = qreal(3.7);+
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    }+
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+
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    qreal target;+
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    uint showNotches : 1;+
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    uint wrapping : 1;+
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    uint doNotEmit : 1;+
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+
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    int valueFromPoint(const QPoint &) const;+
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    double angle(const QPoint &, const QPoint &) const;+
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    void init();+
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};+
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+
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void QDialPrivate::init()+
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{+
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    Q_Q(QDial);+
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    showNotches = false;+
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    q->setFocusPolicy(Qt::WheelFocus);+
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#ifdef QT3_SUPPORT+
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    QObject::connect(q, SIGNAL(sliderPressed()), q, SIGNAL(dialPressed()));+
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    QObject::connect(q, SIGNAL(sliderMoved(int)), q, SIGNAL(dialMoved(int)));+
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    QObject::connect(q, SIGNAL(sliderReleased()), q, SIGNAL(dialReleased()));+
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#endif+
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}+
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+
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/*!+
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    Initialize \a option with the values from this QDial. This method+
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    is useful for subclasses when they need a QStyleOptionSlider, but don't want+
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    to fill in all the information themselves.+
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+
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    \sa QStyleOption::initFrom()+
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*/+
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void QDial::initStyleOption(QStyleOptionSlider *option) const+
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{+
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    if (!option)+
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        return;+
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+
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    Q_D(const QDial);+
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    option->initFrom(this);+
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    option->minimum = d->minimum;+
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    option->maximum = d->maximum;+
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    option->sliderPosition = d->position;+
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    option->sliderValue = d->value;+
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    option->singleStep = d->singleStep;+
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    option->pageStep = d->pageStep;+
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    option->upsideDown = !d->invertedAppearance;+
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    option->notchTarget = d->target;+
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    option->dialWrapping = d->wrapping;+
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    option->subControls = QStyle::SC_All;+
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    option->activeSubControls = QStyle::SC_None;+
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    if (!d->showNotches) {+
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        option->subControls &= ~QStyle::SC_DialTickmarks;+
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        option->tickPosition = QSlider::TicksAbove;+
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    } else {+
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        option->tickPosition = QSlider::NoTicks;+
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    }+
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    option->tickInterval = notchSize();+
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}+
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+
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int QDialPrivate::valueFromPoint(const QPoint &p) const+
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{+
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    Q_Q(const QDial);+
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    double yy = (double)q->height()/2.0 - p.y();+
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    double xx = (double)p.x() - q->width()/2.0;+
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    double a = (xx || yy) ? qAtan2(yy, xx) : 0;+
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+
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    if (a < Q_PI / -2)+
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        a = a + Q_PI * 2;+
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+
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    int dist = 0;+
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    int minv = minimum, maxv = maximum;+
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+
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    if (minimum < 0) {+
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        dist = -minimum;+
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        minv = 0;+
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        maxv = maximum + dist;+
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    }+
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+
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    int r = maxv - minv;+
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    int v;+
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    if (wrapping)+
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        v =  (int)(0.5 + minv + r * (Q_PI * 3 / 2 - a) / (2 * Q_PI));+
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    else+
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        v =  (int)(0.5 + minv + r* (Q_PI * 4 / 3 - a) / (Q_PI * 10 / 6));+
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+
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    if (dist > 0)+
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        v -= dist;+
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+
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    return !invertedAppearance ? bound(v) : maximum - bound(v);+
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}+
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+
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/*!+
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    \class QDial+
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+
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    \brief The QDial class provides a rounded range control (like a speedometer or potentiometer).+
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+
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    \ingroup basicwidgets+
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+
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+
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    QDial is used when the user needs to control a value within a+
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    program-definable range, and the range either wraps around+
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    (for example, with angles measured from 0 to 359 degrees) or the+
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    dialog layout needs a square widget.+
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+
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    Since QDial inherits from QAbstractSlider, the dial behaves in+
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    a similar way to a \l{QSlider}{slider}. When wrapping() is false+
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    (the default setting) there is no real difference between a slider+
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    and a dial. They both share the same signals, slots and member+
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    functions. Which one you use depends on the expectations of+
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    your users and on the type of application.+
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+
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    The dial initially emits valueChanged() signals continuously while+
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    the slider is being moved; you can make it emit the signal less+
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    often by disabling the \l{QAbstractSlider::tracking} {tracking}+
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    property. The sliderMoved() signal is emitted continuously even+
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    when tracking is disabled.+
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+
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    The dial also emits sliderPressed() and sliderReleased() signals+
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    when the mouse button is pressed and released. Note that the+
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    dial's value can change without these signals being emitted since+
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    the keyboard and wheel can also be used to change the value.+
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+
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    Unlike the slider, QDial attempts to draw a "nice" number of+
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    notches rather than one per line step. If possible, the number of+
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    notches drawn is one per line step, but if there aren't enough pixels+
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    to draw every one, QDial will skip notches to try and draw a uniform+
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    set (e.g. by drawing every second or third notch).+
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+
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    Like the slider, the dial makes the QAbstractSlider functions+
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    setValue(), addLine(), subtractLine(), addPage() and+
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    subtractPage() available as slots.+
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+
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    The dial's keyboard interface is fairly simple: The+
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    \key{left}/\key{up} and \key{right}/\key{down} arrow keys adjust+
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    the dial's \l {QAbstractSlider::value} {value} by the defined+
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    \l {QAbstractSlider::singleStep} {singleStep}, \key{Page Up} and+
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    \key{Page Down} by the defined \l {QAbstractSlider::pageStep}+
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    {pageStep}, and the \key Home and \key End keys set the value to+
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    the defined \l {QAbstractSlider::minimum} {minimum} and+
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    \l {QAbstractSlider::maximum} {maximum} values.+
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+
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    If you are using the mouse wheel to adjust the dial, the increment+
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    value is determined by the lesser value of+
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    \l{QApplication::wheelScrollLines()} {wheelScrollLines} multipled+
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    by \l {QAbstractSlider::singleStep} {singleStep}, and+
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    \l {QAbstractSlider::pageStep} {pageStep}.+
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+
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    \table+
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    \row \o \inlineimage plastique-dial.png Screenshot of a dial in the Plastique widget style+
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    \o \inlineimage windowsxp-dial.png Screenshot of a dial in the Windows XP widget style+
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    \o \inlineimage macintosh-dial.png Screenshot of a dial in the Macintosh widget style+
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    \row \o {3,1} Dials shown in various widget styles (from left to right):+
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         \l{Plastique Style Widget Gallery}{Plastique},+
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         \l{Windows XP Style Widget Gallery}{Windows XP},+
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         \l{Macintosh Style Widget Gallery}{Macintosh}.+
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    \endtable+
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+
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    \sa QScrollBar, QSpinBox, QSlider, {fowler}{GUI Design Handbook: Slider}, {Sliders Example}+
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*/+
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+
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/*!+
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    Constructs a dial.+
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+
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    The \a parent argument is sent to the QAbstractSlider constructor.+
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*/+
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QDial::QDial(QWidget *parent)+
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    : QAbstractSlider(*new QDialPrivate, parent)+
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{+
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    Q_D(QDial);+
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    d->init();+
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}+
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+
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#ifdef QT3_SUPPORT+
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/*!+
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    Use one of the constructors that doesn't take the \a name+
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    argument and then use setObjectName() instead.+
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*/+
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QDial::QDial(QWidget *parent, const char *name)+
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    : QAbstractSlider(*new QDialPrivate, parent)+
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{+
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    Q_D(QDial);+
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    setObjectName(QString::fromAscii(name));+
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    d->init();+
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}+
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+
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/*!+
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    Use one of the constructors that doesn't take the \a name+
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    argument and then use setObjectName() instead.+
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*/+
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QDial::QDial(int minValue, int maxValue, int pageStep, int value,+
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              QWidget *parent, const char *name)+
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    : QAbstractSlider(*new QDialPrivate, parent)+
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{+
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    Q_D(QDial);+
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    setObjectName(QString::fromAscii(name));+
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    d->minimum = minValue;+
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    d->maximum = maxValue;+
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    d->pageStep = pageStep;+
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    d->position = d->value = value;+
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    d->init();+
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}+
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#endif+
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/*!+
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    Destroys the dial.+
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*/+
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QDial::~QDial()+
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{+
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}+
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+
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/*! \reimp */+
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void QDial::resizeEvent(QResizeEvent *e)+
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{+
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    QWidget::resizeEvent(e);+
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}+
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+
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/*!+
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  \reimp+
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*/+
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+
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void QDial::paintEvent(QPaintEvent *)+
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{+
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    QStylePainter p(this);+
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    QStyleOptionSlider option;+
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    initStyleOption(&option);+
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    p.drawComplexControl(QStyle::CC_Dial, option);+
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}+
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+
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/*!+
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  \reimp+
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*/+
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+
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void QDial::mousePressEvent(QMouseEvent *e)+
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{+
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    Q_D(QDial);+
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    if (d->maximum == d->minimum ||+
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        (e->button() != Qt::LeftButton)  ||+
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        (e->buttons() ^ e->button())) {+
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        e->ignore();+
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        return;+
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    }+
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    e->accept();+
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    setSliderPosition(d->valueFromPoint(e->pos()));+
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    // ### This isn't quite right,+
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    // we should be doing a hit test and only setting this if it's+
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    // the actual dial thingie (similar to what QSlider does), but we have no+
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    // subControls for QDial.+
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    setSliderDown(true);+
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}+
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+
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+
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/*!+
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  \reimp+
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*/+
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+
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void QDial::mouseReleaseEvent(QMouseEvent * e)+
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{+
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    Q_D(QDial);+
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    if (e->buttons() & (~e->button()) ||+
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       (e->button() != Qt::LeftButton)) {+
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        e->ignore();+
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        return;+
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    }+
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    e->accept();+
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    setValue(d->valueFromPoint(e->pos()));+
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    setSliderDown(false);+
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}+
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+
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+
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/*!+
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  \reimp+
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*/+
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+
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void QDial::mouseMoveEvent(QMouseEvent * e)+
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{+
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    Q_D(QDial);+
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    if (!(e->buttons() & Qt::LeftButton)) {+
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        e->ignore();+
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        return;+
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    }+
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    e->accept();+
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    d->doNotEmit = true;+
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    setSliderPosition(d->valueFromPoint(e->pos()));+
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    d->doNotEmit = false;+
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}+
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+
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+
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/*!+
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    \reimp+
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*/+
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+
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void QDial::sliderChange(SliderChange change)+
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{+
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    QAbstractSlider::sliderChange(change);+
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}+
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+
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void QDial::setWrapping(bool enable)+
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{+
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    Q_D(QDial);+
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    if (d->wrapping == enable)+
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        return;+
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    d->wrapping = enable;+
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    update();+
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}+
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+
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+
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/*!+
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    \property QDial::wrapping+
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    \brief whether wrapping is enabled+
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+
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    If true, wrapping is enabled; otherwise some space is inserted at the bottom+
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    of the dial to separate the ends of the range of valid values.+
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+
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    If enabled, the arrow can be oriented at any angle on the dial. If disabled,+
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    the arrow will be restricted to the upper part of the dial; if it is rotated+
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    into the space at the bottom of the dial, it will be clamped to the closest+
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    end of the valid range of values.+
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+
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    By default this property is false.+
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*/+
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+
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bool QDial::wrapping() const+
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{+
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    Q_D(const QDial);+
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    return d->wrapping;+
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}+
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+
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+
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/*!+
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    \property QDial::notchSize+
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    \brief the current notch size+
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+
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    The notch size is in range control units, not pixels, and if+
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    possible it is a multiple of singleStep() that results in an+
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    on-screen notch size near notchTarget().+
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+
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    By default, this property has a value of 1.+
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+
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    \sa notchTarget(), singleStep()+
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*/+
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+
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int QDial::notchSize() const+
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{+
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    Q_D(const QDial);+
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    // radius of the arc+
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    int r = qMin(width(), height())/2;+
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    // length of the whole arc+
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    int l = (int)(r * (d->wrapping ? 6 : 5) * Q_PI / 6);+
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    // length of the arc from minValue() to minValue()+pageStep()+
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    if (d->maximum > d->minimum + d->pageStep)+
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        l = (int)(0.5 + l * d->pageStep / (d->maximum - d->minimum));+
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    // length of a singleStep arc+
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    l = l * d->singleStep / (d->pageStep ? d->pageStep : 1);+
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    if (l < 1)+
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        l = 1;+
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    // how many times singleStep can be draw in d->target pixels+
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    l = (int)(0.5 + d->target / l);+
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    // we want notchSize() to be a non-zero multiple of lineStep()+
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    if (!l)+
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        l = 1;+
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    return d->singleStep * l;+
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}+
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+
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void QDial::setNotchTarget(double target)+
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{+
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    Q_D(QDial);+
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    d->target = target;+
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    update();+
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}+
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+
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/*!+
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    \property QDial::notchTarget+
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    \brief the target number of pixels between notches+
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+
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    The notch target is the number of pixels QDial attempts to put+
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    between each notch.+
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+
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    The actual size may differ from the target size.+
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+
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    The default notch target is 3.7 pixels.+
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*/+
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qreal QDial::notchTarget() const+
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{+
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    Q_D(const QDial);+
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    return d->target;+
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}+
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+
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+
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void QDial::setNotchesVisible(bool visible)+
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{+
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    Q_D(QDial);+
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    d->showNotches = visible;+
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    update();+
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}+
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+
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/*!+
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    \property QDial::notchesVisible+
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    \brief whether the notches are shown+
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+
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    If the property is true, a series of notches are drawn around the dial+
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    to indicate the range of values available; otherwise no notches are+
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    shown.+
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+
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    By default, this property is disabled.+
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*/+
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bool QDial::notchesVisible() const+
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{+
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    Q_D(const QDial);+
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    return d->showNotches;+
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}+
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+
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/*!+
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  \reimp+
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*/+
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+
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QSize QDial::minimumSizeHint() const+
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{+
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    return QSize(50, 50);+
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}+
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+
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/*!+
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  \reimp+
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*/+
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+
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QSize QDial::sizeHint() const+
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{+
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    return QSize(100, 100).expandedTo(QApplication::globalStrut());+
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}+
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+
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/*!+
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  \reimp+
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*/+
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bool QDial::event(QEvent *e)+
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{+
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    return QAbstractSlider::event(e);+
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}+
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+
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/*!+
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    \fn void QDial::dialPressed();+
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+
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    Use QAbstractSlider::sliderPressed() instead.+
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*/+
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+
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/*!+
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    \fn void QDial::dialMoved(int value);+
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+
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    Use QAbstractSlider::sliderMoved() instead.+
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*/+
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+
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/*!+
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    \fn void QDial::dialReleased();+
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+
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    Use QAbstractSlider::sliderReleased() instead.+
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*/+
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+
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QT_END_NAMESPACE+
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+
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#endif // QT_NO_DIAL+
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