qbrush.cpp

奇趣公司比较新的qt/emd版本

    \sa start()
*/

void QLinearGradient::setStart(const QPointF &start)
{
    Q_ASSERT(m_type == LinearGradient);
    m_data.linear.x1 = start.x();
    m_data.linear.y1 = start.y();
}


/*!
    \fn void QLinearGradient::setFinalStop(qreal x, qreal y)
    \overload
    \since 4.2

    Sets the final stop point of this linear gradient in logical
    coordinates to \a x, \a y.

    \sa start()
*/

/*!
    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);
}


/*!
    \since 4.2

    Sets the final stop point of this linear gradient in logical
    coordinates to \a stop.

    \sa finalStop()
*/

void QLinearGradient::setFinalStop(const QPointF &stop)
{
    Q_ASSERT(m_type == LinearGradient);
    m_data.linear.x2 = stop.x();
    m_data.linear.y2 = stop.y();
}


/*!
    \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
    //### this is hacky because technically we should adjust based on current matrix
    const qreal compensated_radius = radius - 0.0000000001;
    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.

    \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 \a center, \a
    radius and the focal point in the circle center.

    \sa QGradient::setColorAt(), QGradient::setStops()
*/
QRadialGradient::QRadialGradient(const QPointF &center, qreal radius)
{
    m_type = RadialGradient;
    m_spread = PadSpread;
    m_data.radial.cx = center.x();
    m_data.radial.cy = center.y();
    m_data.radial.radius = radius;
    m_data.radial.fx = center.x();
    m_data.radial.fy = center.y();
}


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

    \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();
}

/*!
    Constructs a radial gradient with the center at (\a cx, \a cy) and the
    specified \a radius. The focal point lies at the center of the circle.

    \sa QGradient::setColorAt(), QGradient::setStops()
 */
QRadialGradient::QRadialGradient(qreal cx, qreal cy, qreal radius)
{
    m_type = RadialGradient;
    m_spread = PadSpread;
    m_data.radial.cx = cx;
    m_data.radial.cy = cy;
    m_data.radial.radius = radius;
    m_data.radial.fx = cx;
    m_data.radial.fy = cy;
}


/*!
    Constructs a radial gradient with the center and focal point at
    (0, 0) with a radius of 1.
*/
QRadialGradient::QRadialGradient()
{
    m_type = RadialGradient;
    m_spread = PadSpread;
    m_data.radial.cx = 0;
    m_data.radial.cy = 0;
    m_data.radial.radius = 1;
    m_data.radial.fx = 0;
    m_data.radial.fy = 0;
}


/*!
    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);
}

/*!
    \fn void QRadialGradient::setCenter(qreal x, qreal y)
    \overload
    \since 4.2

    Sets the center of this radial gradient in logical coordinates
    to (\a x, \a y).

    \sa center()
*/

/*!
    \since 4.2

    Sets the center of this radial gradient in logical coordinates
    to \a center.

    \sa center()
*/

void QRadialGradient::setCenter(const QPointF &center)
{
    Q_ASSERT(m_type == RadialGradient);
    m_data.radial.cx = center.x();
    m_data.radial.cy = center.y();
}


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

    \sa QGradient::stops()
*/

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


/*!
    \since 4.2

    Sets the radius of this radial gradient in logical coordinates
    to \a radius
*/
void QRadialGradient::setRadius(qreal radius)
{
    Q_ASSERT(m_type == RadialGradient);
    m_data.radial.radius = 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);
}

/*!
    \fn void QRadialGradient::setFocalPoint(qreal x, qreal y)
    \overload
    \since 4.2

    Sets the focal point of this radial gradient in logical
    coordinates to (\a x, \a y).

    \sa focalPoint()
*/

/*!
    \since 4.2

    Sets the focal point of this radial gradient in logical
    coordinates to \a focalPoint.

    \sa focalPoint()
*/

void QRadialGradient::setFocalPoint(const QPointF &focalPoint)
{
    Q_ASSERT(m_type == RadialGradient);
    m_data.radial.fx = focalPoint.x();
    m_data.radial.fy = focalPoint.y();
}



/*!
    \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.png

    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 gradient 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 QGradient::setColorAt(), QGradient::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 gradient 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 QGradient::setColorAt(), QGradient::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;
}


/*!
    Constructs a conical with center at (0, 0) starting the
    interpolation at angle 0.

    \sa QGradient::setColorAt(), setCenter(), setAngle()
*/

QConicalGradient::QConicalGradient()
{
    m_type = ConicalGradient;
    m_spread = PadSpread;
    m_data.conical.cx = 0;
    m_data.conical.cy = 0;
    m_data.conical.angle = 0;
}


/*!
    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);
}


/*!
    \fn void QConicalGradient::setCenter(qreal x, qreal y)

    \overload

    Sets the center of this conical gradient in logical coordinates to
    (\a x, \a y).

    \sa center()
*/

/*!
    Sets the center of this conical gradient in logical coordinates to
    \a center.

    \sa center()
*/

void QConicalGradient::setCenter(const QPointF &center)
{
    Q_ASSERT(m_type == ConicalGradient);
    m_data.conical.cx = center.x();
    m_data.conical.cy = center.y();
}

/*!
    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;
}


/*!
    \since 4.2

    Sets \a angle to be the start angle for this conical gradient in
    logical coordinates.

    \sa angle()
*/

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

/*!
    \typedef QGradientStop
    \relates QGradient

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

/*!
    \typedef QGradientStops
    \relates QGradient

    Typedef for QVector<QGradientStop>.
*/

/*!
    \typedef QBrush::DataPtr
    \internal
*/

/*!
    \fn DataPtr &QBrush::data_ptr()
    \internal
*/


/*!
    \fn bool QBrush::isDetached() const
    \internal
*/

/*!
    \fn QTransform QBrush::transform() const
    \since 4.3

    Returns the current transformation matrix for the brush.

    \sa setTransform()
*/