qmatrix.cpp

奇趣公司比较新的qt/emd版本

    The rectangle's coordinates are transformed using the following
    formulas:

    \code
        x' = m11*x + m21*y + dx
        y' = m22*y + m12*x + dy
    \endcode

    If rotation or shearing has been specified, this function returns
    the \e bounding rectangle. To retrieve the exact region the given
    \a rectangle maps to, use the mapToPolygon() function instead.

    \sa mapToPolygon(), {QMatrix#Basic Matrix Operations}{Basic Matrix
    Operations}
*/
QRectF QMatrix::mapRect(const QRectF &rect) const
{
    QRectF result;
    if (_m12 == 0.0F && _m21 == 0.0F) {
        qreal x = _m11*rect.x() + _dx;
        qreal y = _m22*rect.y() + _dy;
        qreal w = _m11*rect.width();
        qreal h = _m22*rect.height();
        if (w < 0) {
            w = -w;
            x -= w;
        }
        if (h < 0) {
            h = -h;
            y -= h;
        }
        result = QRectF(x, y, w, h);
    } else {
        qreal x0, y0;
        qreal x, y;
        MAPDOUBLE(rect.x(), rect.y(), x0, y0);
        qreal xmin = x0;
        qreal ymin = y0;
        qreal xmax = x0;
        qreal ymax = y0;
        MAPDOUBLE(rect.x() + rect.width(), rect.y(), x, y);
        xmin = qMin(xmin, x);
        ymin = qMin(ymin, y);
        xmax = qMax(xmax, x);
        ymax = qMax(ymax, y);
        MAPDOUBLE(rect.x() + rect.width(), rect.y() + rect.height(), x, y);
        xmin = qMin(xmin, x);
        ymin = qMin(ymin, y);
        xmax = qMax(xmax, x);
        ymax = qMax(ymax, y);
        MAPDOUBLE(rect.x(), rect.y() + rect.height(), x, y);
        xmin = qMin(xmin, x);
        ymin = qMin(ymin, y);
        xmax = qMax(xmax, x);
        ymax = qMax(ymax, y);
        result = QRectF(xmin, ymin, xmax-xmin, ymax - ymin);
    }
    return result;
}

/*!
    \fn QRect QMatrix::mapRect(const QRect &rectangle) const
    \overload

    Creates and returns a QRect object that is a copy of the given \a
    rectangle, mapped into the coordinate system defined by this
    matrix. Note that the transformed coordinates are rounded to the
    nearest integer.
*/


/*!
    \fn QPoint operator*(const QPoint &point, const QMatrix &matrix)
    \relates QMatrix

    This is the same as \a{matrix}.map(\a{point}).

    \sa QMatrix::map()
*/

QPoint QMatrix::map(const QPoint &p) const
{
    qreal fx = p.x();
    qreal fy = p.y();
    return QPoint(qRound(_m11*fx + _m21*fy + _dx),
                   qRound(_m12*fx + _m22*fy + _dy));
}

/*!
    \fn QPointF operator*(const QPointF &point, const QMatrix &matrix)
    \relates QMatrix

    Same as \a{matrix}.map(\a{point}).

    \sa QMatrix::map()
*/

/*!
    \overload

    Creates and returns a QPointF object that is a copy of the given
    \a point, mapped into the coordinate system defined by this
    matrix.
*/
QPointF QMatrix::map(const QPointF &point) const
{
    qreal fx = point.x();
    qreal fy = point.y();
    return QPointF(_m11*fx + _m21*fy + _dx, _m12*fx + _m22*fy + _dy);
}

/*!
    \fn QPoint QMatrix::map(const QPoint &point) const
    \overload

    Creates and returns a QPoint object that is a copy of the given \a
    point, mapped into the coordinate system defined by this
    matrix. Note that the transformed coordinates are rounded to the
    nearest integer.
*/

/*!
    \fn QLineF operator*(const QLineF &line, const QMatrix &matrix)
    \relates QMatrix

    This is the same as \a{matrix}.map(\a{line}).

    \sa QMatrix::map()
*/

/*!
    \fn QLine operator*(const QLine &line, const QMatrix &matrix)
    \relates QMatrix

    This is the same as \a{matrix}.map(\a{line}).

    \sa QMatrix::map()
*/

/*!
    \overload

    Creates and returns a QLineF object that is a copy of the given \a
    line, mapped into the coordinate system defined by this matrix.
*/
QLineF QMatrix::map(const QLineF &line) const
{
    return QLineF(map(line.p1()), map(line.p2()));
}

/*!
    \overload

    Creates and returns a QLine object that is a copy of the given \a
    line, mapped into the coordinate system defined by this matrix.
    Note that the transformed coordinates are rounded to the nearest
    integer.
*/
QLine QMatrix::map(const QLine &line) const
{
    return QLine(map(line.p1()), map(line.p2()));
}

/*!
    \fn QPolygonF operator *(const QPolygonF &polygon, const QMatrix &matrix)
    \relates QMatrix

    This is the same as \a{matrix}.map(\a{polygon}).

    \sa QMatrix::map()
*/

/*!
    \fn QPolygon operator*(const QPolygon &polygon, const QMatrix &matrix)
    \relates QMatrix

    This is the same as \a{matrix}.map(\a{polygon}).

    \sa QMatrix::map()
*/

QPolygon QMatrix::map(const QPolygon &a) const
{
    int size = a.size();
    int i;
    QPolygonF p(size);
    const QPoint *da = a.constData();
    QPointF *dp = p.data();
    qreal xmin = qreal(INT_MAX);
    qreal ymin = xmin;
    qreal xmax = qreal(INT_MIN);
    qreal ymax = xmax;
    int xminp = 0;
    int yminp = 0;
    for(i = 0; i < size; i++) {
        dp[i].xp = da[i].x();
        dp[i].yp = da[i].y();
        if (dp[i].xp < xmin) {
            xmin = dp[i].xp;
            xminp = i;
        }
        if (dp[i].yp < ymin) {
            ymin = dp[i].yp;
            yminp = i;
        }
        xmax = qMax(xmax, dp[i].xp);
        ymax = qMax(ymax, dp[i].yp);
    }
    qreal w = qMax<qreal>(xmax - xmin, 1.);
    qreal h = qMax<qreal>(ymax - ymin, 1.);
    for(i = 0; i < size; i++) {
        dp[i].xp += (dp[i].xp - xmin)/w;
        dp[i].yp += (dp[i].yp - ymin)/h;
        MAPDOUBLE(dp[i].xp, dp[i].yp, dp[i].xp, dp[i].yp);
    }

    // now apply correction back for transformed values...
    xmin = qreal(INT_MAX/256);
    ymin = xmin;
    xmax = qreal(INT_MIN/256);
    ymax = xmax;
    for(i = 0; i < size; i++) {
        xmin = qMin<qreal>(xmin, dp[i].xp);
        ymin = qMin<qreal>(ymin, dp[i].yp);
        xmax = qMax<qreal>(xmax, dp[i].xp);
        ymax = qMax<qreal>(ymax, dp[i].yp);
    }
    w = qMax<qreal>(xmax - xmin, 1.);
    h = qMax<qreal>(ymax - ymin, 1.);

    QPolygon result(size);
    QPoint *dr = result.data();
    for(i = 0; i < size; i++) {
        dr[i].setX(qRound(dp[i].xp - (dp[i].xp - dp[xminp].xp)/w));
        dr[i].setY(qRound(dp[i].yp - (dp[i].yp - dp[yminp].yp)/h));
    }
    return result;
}

/*!
    \fn QPolygonF QMatrix::map(const QPolygonF &polygon) const
    \overload

    Creates and returns a QPolygonF object that is a copy of the given
    \a polygon, mapped into the coordinate system defined by this
    matrix.
*/
QPolygonF QMatrix::map(const QPolygonF &a) const
{
    int size = a.size();
    int i;
    QPolygonF p(size);
    const QPointF *da = a.constData();
    QPointF *dp = p.data();
    for(i = 0; i < size; i++) {
        MAPDOUBLE(da[i].xp, da[i].yp, dp[i].xp, dp[i].yp);
    }
    return p;
}

/*!
    \fn QPolygon QMatrix::map(const QPolygon &polygon) const
    \overload

    Creates and returns a QPolygon object that is a copy of the given
    \a polygon, mapped into the coordinate system defined by this
    matrix. Note that the transformed coordinates are rounded to the
    nearest integer.
*/

/*!
    \fn QRegion operator*(const QRegion &region, const QMatrix &matrix)
    \relates QMatrix

    This is the same as \a{matrix}.map(\a{region}).

    \sa QMatrix::map()
*/

/*!
    \fn QRegion QMatrix::map(const QRegion &region) const
    \overload

    Creates and returns a QRegion object that is a copy of the given
    \a region, mapped into the coordinate system defined by this matrix.

    Calling this method can be rather expensive if rotations or
    shearing are used.
*/
QRegion QMatrix::map(const QRegion &r) const
{
    if (_m11 == 1.0 && _m22 == 1.0 && _m12 == 0.0 && _m21 == 0.0) { // translate or identity
        if (_dx == 0.0 && _dy == 0.0) // Identity
            return r;
        QRegion copy(r);
        copy.translate(qRound(_dx), qRound(_dy));
        return copy;
    }

    QPainterPath p;
    p.addRegion(r);
    p = map(p);
    return p.toFillPolygon().toPolygon();
}

/*!
    \fn QPainterPath operator *(const QPainterPath &path, const QMatrix &matrix)
    \relates QMatrix

    This is the same as \a{matrix}.map(\a{path}).

    \sa QMatrix::map()
*/

/*!
    \overload

    Creates and returns a QPainterPath object that is a copy of the
    given \a path, mapped into the coordinate system defined by this
    matrix.
*/
QPainterPath QMatrix::map(const QPainterPath &path) const
{
    if (path.isEmpty())
        return QPainterPath();

    QPainterPath copy = path;

    // Translate or identity
    if (_m11 == 1.0 && _m22 == 1.0 && _m12 == 0.0 && _m21 == 0.0) {

        // Translate
        if (_dx != 0.0 || _dy != 0.0) {
            copy.detach();
            for (int i=0; i<path.elementCount(); ++i) {
                QPainterPath::Element &e = copy.d_ptr->elements[i];
                e.x += _dx;
                e.y += _dy;
            }
        }

    // Full xform
    } else {
        copy.detach();
        for (int i=0; i<path.elementCount(); ++i) {
            QPainterPath::Element &e = copy.d_ptr->elements[i];
            qreal fx = e.x, fy = e.y;
            e.x = _m11*fx + _m21*fy + _dx;
            e.y =  _m12*fx + _m22*fy + _dy;
        }
    }

    return copy;
}

/*!
    \fn QRegion QMatrix::mapToRegion(const QRect &rectangle) const

    Returns the transformed rectangle \a rectangle as a QRegion
    object. A rectangle which has been rotated or sheared may result
    in a non-rectangular region being returned.

    Use the mapToPolygon() or map() function instead.
*/
#ifdef QT3_SUPPORT
QRegion QMatrix::mapToRegion(const QRect &rect) const
{
    QRegion result;
    if (isIdentity()) {
        result = rect;
    } else if (m12() == 0.0F && m21() == 0.0F) {
        int x = qRound(m11()*rect.x() + dx());
        int y = qRound(m22()*rect.y() + dy());
        int w = qRound(m11()*rect.width());
        int h = qRound(m22()*rect.height());
        if (w < 0) {
            w = -w;
            x -= w - 1;
        }
        if (h < 0) {
            h = -h;
            y -= h - 1;
        }
        result = QRect(x, y, w, h);
    } else {
        result = QRegion(mapToPolygon(rect));
    }
    return result;

}
#endif
/*!
    \fn QPolygon QMatrix::mapToPolygon(const QRect &rectangle) const

    Creates and returns a QPolygon representation of the given \a
    rectangle, mapped into the coordinate system defined by this
    matrix.

    The rectangle's coordinates are transformed using the following
    formulas:

    \code
        x' = m11*x + m21*y + dx
        y' = m22*y + m12*x + dy
    \endcode

    Polygons and rectangles behave slightly differently when
    transformed (due to integer rounding), so
    \c{matrix.map(QPolygon(rectangle))} is not always the same as
    \c{matrix.mapToPolygon(rectangle)}.

    \sa mapRect(), {QMatrix#Basic Matrix Operations}{Basic Matrix
    Operations}