qprogressbar.cpp

奇趣公司比较新的qt/emd版本

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#include "qprogressbar.h"
#ifndef QT_NO_PROGRESSBAR
#include <qevent.h>
#include <qpainter.h>
#include <qstylepainter.h>
#include <qstyleoption.h>
#include <private/qwidget_p.h>
#ifndef QT_NO_ACCESSIBILITY
#include <qaccessible.h>
#endif
#include <limits.h>

class QProgressBarPrivate : public QWidgetPrivate
{
    Q_DECLARE_PUBLIC(QProgressBar)

public:
    QProgressBarPrivate();

    void init();
    inline void resetLayoutItemMargins();

    int minimum;
    int maximum;
    int value;
    Qt::Alignment alignment;
    uint textVisible : 1;
    int lastPaintedValue;
    Qt::Orientation orientation;
    bool invertedAppearance;
    QProgressBar::Direction textDirection;
    QString format;
    inline int bound(int val) const { return qMax(minimum-1, qMin(maximum, val)); }
    bool repaintRequired() const;
};

QProgressBarPrivate::QProgressBarPrivate()
    : minimum(0), maximum(100), value(-1), alignment(Qt::AlignLeft), textVisible(true),
      lastPaintedValue(-1), orientation(Qt::Horizontal), invertedAppearance(false),
      textDirection(QProgressBar::TopToBottom), format(QLatin1String("%p%"))
{
}

void QProgressBarPrivate::init()
{
    Q_Q(QProgressBar);
    QSizePolicy sp(QSizePolicy::Expanding, QSizePolicy::Fixed);
    if (orientation == Qt::Vertical)
        sp.transpose();
    q->setSizePolicy(sp);
    q->setAttribute(Qt::WA_WState_OwnSizePolicy, false);
    resetLayoutItemMargins();
}

void QProgressBarPrivate::resetLayoutItemMargins()
{
    Q_Q(QProgressBar);
    QStyleOptionProgressBar option;
    q->initStyleOption(&option);
    setLayoutItemMargins(QStyle::SE_ProgressBarLayoutItem, &option);
}

/*!
    Initialize \a option with the values from this QProgressBar. This method is useful
    for subclasses when they need a QStyleOptionProgressBar or QStyleOptionProgressBarV2,
    but don't want to fill in all the information themselves. This function will check the version
    of the QStyleOptionProgressBar and fill in the additional values for a
    QStyleOptionProgressBarV2.

    \sa QStyleOption::initFrom()
*/
void QProgressBar::initStyleOption(QStyleOptionProgressBar *option) const
{
    if (!option)
        return;
    Q_D(const QProgressBar);
    option->initFrom(this);

    if (d->orientation == Qt::Horizontal)
        option->state |= QStyle::State_Horizontal;
    option->minimum = d->minimum;
    option->maximum = d->maximum;
    option->progress = d->value;
    option->textAlignment = d->alignment;
    option->textVisible = d->textVisible;
    option->text = text();

    if (QStyleOptionProgressBarV2 *optionV2
            = qstyleoption_cast<QStyleOptionProgressBarV2 *>(option)) {
        optionV2->orientation = d->orientation;  // ### Qt 5: use State_Horizontal instead
        optionV2->invertedAppearance = d->invertedAppearance;
        optionV2->bottomToTop = (d->textDirection == QProgressBar::BottomToTop);
    }
}

bool QProgressBarPrivate::repaintRequired() const
{
    Q_Q(const QProgressBar);
    if (value == lastPaintedValue)
        return false;

    int valueDifference = qAbs(value - lastPaintedValue);

    // Check if the text needs to be repainted
    if (value == minimum || value == maximum)
        return true;
    if (textVisible) {
        if ((format.contains(QLatin1String("%v"))))
            return true;
        if ((format.contains(QLatin1String("%p"))
             && valueDifference >= qAbs((maximum - minimum) / 100)))
            return true;
    }

    // Check if the bar needs to be repainted
    QStyleOptionProgressBarV2 opt;
    q->initStyleOption(&opt);
    int cw = q->style()->pixelMetric(QStyle::PM_ProgressBarChunkWidth, &opt, q);
    QRect groove  = q->style()->subElementRect(QStyle::SE_ProgressBarGroove, &opt, q);
    // This expression is basically
    // (valueDifference / (maximum - minimum) > cw / groove.width())
    // transformed to avoid integer division.
    return (valueDifference * groove.width() > cw * (maximum - minimum));
}

/*!
    \class QProgressBar qprogressbar.h
    \brief The QProgressBar widget provides a horizontal or vertical progress bar.

    \ingroup advanced
    \mainclass

    A progress bar is used to give the user an indication of the
    progress of an operation and to reassure them that the application
    is still running.

    The progress bar uses the concept of \e steps. You set it up by
    specifying the minimum and maximum possible step values, and it
    will display the percentage of steps that have been completed
    when you later give it the current step value. The percentage is
    calculated by dividing the progress (value() - minimum()) divided
    by maximum() - minimum().

    You can specify the minimum and maximum number of steps with
    setMinimum() and setMaximum. The current number of steps is set
    with setValue(). The progress bar can be rewound to the
    beginning with reset().

    If minimum and maximum both are set to 0, the bar shows a busy indicator
    instead of a percentage of steps. This is useful, for example, when using
    QFtp or QHttp to download items when they are unable to determine the
    size of the item being downloaded.

    \table
    \row \o \inlineimage macintosh-progressbar.png Screenshot of a Macintosh style progress bar
         \o A progress bar shown in the Macintosh widget style.
    \row \o \inlineimage windowsxp-progressbar.png Screenshot of a Windows XP style progress bar
         \o A progress bar shown in the Windows XP widget style.
    \row \o \inlineimage plastique-progressbar.png Screenshot of a Plastique style progress bar
         \o A progress bar shown in the Plastique widget style.
    \endtable

    \sa QTimeLine, QProgressDialog, {fowler}{GUI Design Handbook: Progress Indicator}
*/

/*!
    \since 4.1
    \enum QProgressBar::Direction
    \brief Specifies the reading direction of the \l text for vertical progress bars.

    \value TopToBottom The text is rotated 90 degrees clockwise.
    \value BottomToTop The text is rotated 90 degrees counter-clockwise.

    Note that whether or not the text is drawn is dependent on the style.
    Currently CDE, CleanLooks, Motif, and Plastique draw the text. Mac, Windows
    and WindowsXP style do not.

    \sa textDirection
*/

/*!
    \fn void QProgressBar::valueChanged(int value)

    This signal is emitted when the value shown in the progress bar changes.
    \a value is the new value shown by the progress bar.
*/

/*!
    Constructs a progress bar with the given \a parent.

    By default, the minimum step value is set to 0, and the maximum to 100.

    \sa setRange()
*/

QProgressBar::QProgressBar(QWidget *parent)
    : QWidget(*(new QProgressBarPrivate), parent, 0)
{
    d_func()->init();
}

/*!
    Reset the progress bar. The progress bar "rewinds" and shows no
    progress.
*/

void QProgressBar::reset()
{
    Q_D(QProgressBar);
    d->value = d->minimum - 1;
    if (d->minimum == INT_MIN)
        d->value = INT_MIN;
    repaint();
}

/*!
    \property QProgressBar::minimum
    \brief the progress bar's minimum value

    When setting this property, the \l maximum is adjusted if
    necessary to ensure that the range remains valid. If the
    current value falls outside the new range, the progress bar is reset
    with reset().
*/
void QProgressBar::setMinimum(int minimum)
{
    setRange(minimum, qMax(d_func()->maximum, minimum));
}

int QProgressBar::minimum() const
{
    return d_func()->minimum;
}


/*!
    \property QProgressBar::maximum
    \brief the progress bar's maximum value

    When setting this property, the \l minimum is adjusted if
    necessary to ensure that the range remains valid. If the
    current value falls outside the new range, the progress bar is reset
    with reset().
*/

void QProgressBar::setMaximum(int maximum)
{
    setRange(qMin(d_func()->minimum, maximum), maximum);
}

int QProgressBar::maximum() const
{
    return d_func()->maximum;
}

/*!