qbrush.cpp

qt-x11-opensource-src-4.1.4.tar.gz源码

    \sa spread()
*/

/*!
    \fn QGradient::Spread QGradient::spread() const

    Returns the spread method use by this gradient. The default is
    PadSpread.

    \sa setSpread()
*/

/*!
    \fn QGradient::Type QGradient::type() const

    Returns the type of gradient.
*/

/*!
    \fn void QGradient::setColorAt(qreal position, const QColor &color)

    Creates a stop point at the given \a position with the given \a
    color. The given \a position must be in the range 0 to 1.

    \sa setStops(), stops()
*/

void QGradient::setColorAt(qreal pos, const QColor &color)
{
    if (pos > 1 || pos < 0) {
        qWarning("QGradient::setColorAt(), colors positions must be specified in the range 0 to 1");
        return;
    }

    int index = 0;
    while (index < m_stops.size() && m_stops.at(index).first < pos) ++index;
    m_stops.insert(index, QGradientStop(pos, color));
}

/*!
    \fn void QGradient::setStops(const QGradientStops &stopPoints)

    Replaces the current set of stop points with the given \a
    stopPoints. The positions of the points must be in the range 0 to
    1, and must be sorted with the lowest point first.

    \sa setColorAt(), stops()
*/
void QGradient::setStops(const QGradientStops &stops)
{
    m_stops.clear();
    for (int i=0; i<stops.size(); ++i)
        setColorAt(stops.at(i).first, stops.at(i).second);
}


/*!
    Returns the stop points for this gradient.

    If no stop points have been specified, a gradient of black at 0 to white
    at 1 is used.

    \sa setStops(), setColorAt()
*/
QGradientStops QGradient::stops() const
{
    if (m_stops.isEmpty()) {
        QGradientStops tmp;
        tmp << QGradientStop(0, Qt::black) << QGradientStop(1, Qt::white);
        return tmp;
    }
    return m_stops;
}


/*!
    \internal
*/
bool QGradient::operator==(const QGradient &gradient) const
{
    if (gradient.m_type != m_type || gradient.m_spread != m_spread) return false;

    if (m_type == LinearGradient) {
        if (m_data.linear.x1 != gradient.m_data.linear.x1
            || m_data.linear.y1 != gradient.m_data.linear.y1
            || m_data.linear.x2 != gradient.m_data.linear.x2
            || m_data.linear.y2 != gradient.m_data.linear.y2)
            return false;
    } else if (m_type == RadialGradient) {
        if (m_data.radial.cx != gradient.m_data.radial.cx
            || m_data.radial.cy != gradient.m_data.radial.cy
            || m_data.radial.fx != gradient.m_data.radial.fx
            || m_data.radial.fy != gradient.m_data.radial.fy
            || m_data.radial.radius != gradient.m_data.radial.radius)
            return false;
    } else { // m_type == ConicalGradient
        if (m_data.conical.cx != gradient.m_data.conical.cx
            || m_data.conical.cy != gradient.m_data.conical.cy
            || m_data.conical.angle != gradient.m_data.conical.angle)
            return false;
    }

    return stops() == gradient.stops();
}

/*!
    Returns true if the gradient is the same as the other \a gradient
    specified; otherwise returns false.
*/
bool QGradient::operator==(const QGradient &gradient)
{
    return const_cast<const QGradient *>(this)->operator==(gradient);
}


/*!
    \class QLinearGradient
    \ingroup multimedia

    \brief The QLinearGradient class is used in combination with QBrush to
    specify a linear gradient brush.

    Linear gradients interpolate colors between start and end
    points. Outside these points the gradient is either padded,
    reflected or repeated depending on the currently set \l
    {QGradient::Spread}{spread} method:

    \table
    \row
    \o \inlineimage qlineargradient-pad.png
    \o \inlineimage qlineargradient-reflect.png
    \o \inlineimage qlineargradient-repeat.png
    \row
    \o \l {QGradient::PadSpread}{PadSpread} (default)
    \o \l {QGradient::ReflectSpread}{ReflectSpread}
    \o \l {QGradient::RepeatSpread}{RepeatSpread}
    \endtable

    The colors in a gradient is defined using stop points of the
    QGradientStop type, i.e. a position and a color. Use the
    QGradient::setColorAt() or the QGradient::setStops() function to
    define the stop points. It is the gradient's complete set of stop
    points that describes how the gradient area should be filled. If
    no stop points have been specified, a gradient of black at 0 to
    white at 1 is used.

    In addition to the functions inherited from QGradient, the
    QLinearGradient class provides the finalStop() function which
    returns the final stop point of the gradient, and the start()
    function returning the start point of the gradient.

    \sa QRadialGradient, QConicalGradient, {demos/gradients}{The
    Gradients Demo}
*/


/*!
    Constructs a linear gradient with interpolation area between the
    given \a start point and \a finalStop.

    \sa QGradient::setColorAt(), QGradient::setStops()
*/
QLinearGradient::QLinearGradient(const QPointF &start, const QPointF &finalStop)
{
    m_type = LinearGradient;
    m_spread = PadSpread;
    m_data.linear.x1 = start.x();
    m_data.linear.y1 = start.y();
    m_data.linear.x2 = finalStop.x();
    m_data.linear.y2 = finalStop.y();
}

/*!
    \fn QLinearGradient::QLinearGradient(qreal x1, qreal y1, qreal x2, qreal y2)

    Constructs a linear gradient with interpolation area between (\a
    x1, \a y1) and (\a x2, \a y2).

    \sa QGradient::setColorAt(), QGradient::setStops()
*/
QLinearGradient::QLinearGradient(qreal xStart, qreal yStart, qreal xFinalStop, qreal yFinalStop)
{
    m_type = LinearGradient;
    m_spread = PadSpread;
    m_data.linear.x1 = xStart;
    m_data.linear.y1 = yStart;
    m_data.linear.x2 = xFinalStop;
    m_data.linear.y2 = yFinalStop;
}


/*!
    Returns the start point of this linear gradient in logical coordinates.

    \sa QGradient::stops()
*/

QPointF QLinearGradient::start() const
{
    Q_ASSERT(m_type == LinearGradient);
    return QPointF(m_data.linear.x1, m_data.linear.y1);
}


/*!
    Returns the final stop point of this linear gradient in logical coordinates.

    \sa QGradient::stops()
*/

QPointF QLinearGradient::finalStop() const
{
    Q_ASSERT(m_type == LinearGradient);
    return QPointF(m_data.linear.x2, m_data.linear.y2);
}


/*!
    \class QRadialGradient
    \ingroup multimedia

    \brief The QRadialGradient class is used in combination with QBrush to
    specify a radial gradient brush.

    Radial gradients interpolate colors between a focal point and end
    points on a circle surrounding it. Outside the end points the
    gradient is either padded, reflected or repeated depending on the
    currently set \l {QGradient::Spread}{spread} method:

    \table
    \row
    \o \inlineimage qradialgradient-pad.png
    \o \inlineimage qradialgradient-reflect.png
    \o \inlineimage qradialgradient-repeat.png
    \row
    \o \l {QGradient::PadSpread}{PadSpread} (default)
    \o \l {QGradient::ReflectSpread}{ReflectSpread}
    \o \l {QGradient::RepeatSpread}{RepeatSpread}
    \endtable

    The colors in a gradient is defined using stop points of the
    QGradientStop type, i.e. a position and a color. Use the
    QGradient::setColorAt() or the QGradient::setStops() function to
    define the stop points. It is the gradient's complete set of stop
    points that describes how the gradient area should be filled.  If
    no stop points have been specified, a gradient of black at 0 to
    white at 1 is used.

    In addition to the functions inherited from QGradient, the
    QRadialGradient class provides the center(), focalPoint() and
    radius() functions returning the gradient's center, focal point
    and radius respectively.

    \sa QLinearGradient, QConicalGradient, {demos/gradients}{The
    Gradients Demo}
*/

static QPointF qt_radial_gradient_adapt_focal_point(const QPointF &center,
                                                    qreal radius,
                                                    const QPointF &focalPoint)
{
    // We have a one pixel buffer zone to avoid numerical instability on the
    // circle border
    const qreal compensated_radius = radius - 1;
    QLineF line(center, focalPoint);
    if (line.length() >= (compensated_radius))
        line.setLength(compensated_radius);
    return line.p2();
}

/*!
    Constructs a radial gradient with the given \a center, \a
    radius and \a focalPoint.

    The default focalPoint is the circle center. If the \a focalPoint
    is outside the circle defined by the given \a center and \a
    radius, it is clamped to the circle's boundary.

    \sa QGradient::setColorAt(), QGradient::setStops()
*/

QRadialGradient::QRadialGradient(const QPointF &center, qreal radius, const QPointF &focalPoint)
{
    m_type = RadialGradient;
    m_spread = PadSpread;
    m_data.radial.cx = center.x();
    m_data.radial.cy = center.y();
    m_data.radial.radius = radius;

    QPointF adapted_focal = qt_radial_gradient_adapt_focal_point(center, radius, focalPoint);
    m_data.radial.fx = adapted_focal.x();
    m_data.radial.fy = adapted_focal.y();
}



/*!
    Constructs a radial gradient with the given center (\a cx, \a cy),
    \a radius and focal point (\a fx, \a fy).

    The default focal point is the circle center. If the focal point
    is outside the circle defined by the given center and \a radius,
    it is clamped to the circle's boundary.

    \sa QGradient::setColorAt(), QGradient::setStops()
*/

QRadialGradient::QRadialGradient(qreal cx, qreal cy, qreal radius, qreal fx, qreal fy)
{
    m_type = RadialGradient;
    m_spread = PadSpread;
    m_data.radial.cx = cx;
    m_data.radial.cy = cy;
    m_data.radial.radius = radius;

    QPointF adapted_focal = qt_radial_gradient_adapt_focal_point(QPointF(cx, cy),
                                                                 radius,
                                                                 QPointF(fx, fy));

    m_data.radial.fx = adapted_focal.x();
    m_data.radial.fy = adapted_focal.y();
}


/*!
    Returns the center of this radial gradient in logical coordinates.

    \sa QGradient::stops()
*/

QPointF QRadialGradient::center() const
{
    Q_ASSERT(m_type == RadialGradient);
    return QPointF(m_data.radial.cx, m_data.radial.cy);
}


/*!
    Returns the radius of the radial gradient in logical coordinates.

    \sa QGradient::stops()
*/

qreal QRadialGradient::radius() const
{
    Q_ASSERT(m_type == RadialGradient);
    return m_data.radial.radius;
}


/*!
    Returns the focal point of this radial gradient in logical
    coordinates.

    \sa QGradient::stops()
*/

QPointF QRadialGradient::focalPoint() const
{
    Q_ASSERT(m_type == RadialGradient);
    return QPointF(m_data.radial.fx, m_data.radial.fy);
}


/*!
    \class QConicalGradient
    \ingroup multimedia

    \brief The QConicalGradient class is used in combination with QBrush to
    specify a conical gradient brush.

    Conical gradients interpolate interpolate colors counter-clockwise
    around a center point.

    \image qconicalgradient

    The colors in a gradient is defined using stop points of the
    QGradientStop type, i.e. a position and a color. Use the
    QGradient::setColorAt() or the QGradient::setStops() function to
    define the stop points. It is the gradient's complete set of stop
    points that describes how the gradient area should be filled. If
    no stop points have been specified, a gradient of black at 0 to
    white at 1 is used.

    In addition to the functions inherited from QGradient, the
    QConicalGradient class provides the angle() and center() functions
    returning the start angle and center of the gradient.

    Note that the setSpread() function has no effect for conical
    gradients. The reason is that the conical gradient is closed by
    definition, i.e. the conical gradient fills the entire circle from
    0 - 360 degrees, while the boundary of a radial or a linear
    gradient can be specified through its radius or final stop points,
    respectively.

    \sa QLinearGradient, QRadialGradient, {demos/gradients}{The
    Gradients Demo}
*/


/*!
    Constructs a conical with the given \a center, starting the
    interpolation at the given \a angle. The \a angle must be specified in
    degrees between 0 and 360.

    \sa setColorAt(), setStops()
*/

QConicalGradient::QConicalGradient(const QPointF &center, qreal angle)
{
    m_type = ConicalGradient;
    m_spread = PadSpread;
    m_data.conical.cx = center.x();
    m_data.conical.cy = center.y();
    m_data.conical.angle = angle;
}


/*!
    Constructs a conical with the given center (\a cx, \a cy),
    starting the interpolation at the given \a angle. The angle must
    be specified in degrees between 0 and 360.

    \sa setColorAt(), setStops()
*/

QConicalGradient::QConicalGradient(qreal cx, qreal cy, qreal angle)
{
    m_type = ConicalGradient;
    m_spread = PadSpread;
    m_data.conical.cx = cx;
    m_data.conical.cy = cy;
    m_data.conical.angle = angle;
}


/*!
    Returns the center of the conical gradient in logical coordinates

    \sa stops()
*/

QPointF QConicalGradient::center() const
{
    Q_ASSERT(m_type == ConicalGradient);
    return QPointF(m_data.conical.cx, m_data.conical.cy);
}


/*!
    Returns the start angle of the conical gradient in logical coordinates

    \sa stops()
*/

qreal QConicalGradient::angle() const
{
    Q_ASSERT(m_type == ConicalGradient);
    return m_data.conical.angle;
}

/*!
    \typedef QGradientStop
    \relates QGradient

    Typedef for QPair<\l qreal, QColor>.
*/

/*!
    \typedef QGradientStops
    \relates QGradient

    Typedef for QVector<QGradientStop>.
*/