qtransform.cpp

奇趣公司比较新的qt/emd版本

        x[2] = x[1];
        x[3] = x[0];
        y[1] = y[0];
        y[2] = y[0]+h;
        y[3] = y[2];
    } else {
        qreal right = rect.x() + rect.width();
        qreal bottom = rect.y() + rect.height();
        qreal fx, fy;
        MAPDOUBLE(rect.x(), rect.y(), x[0], y[0]);
        MAPDOUBLE(right, rect.y(), x[1], y[1]);
        MAPDOUBLE(right, bottom, x[2], y[2]);
        MAPDOUBLE(rect.x(), bottom, x[3], y[3]);
    }

    // all coordinates are correctly, tranform to a pointarray
    // (rounding to the next integer)
    a.setPoints(4, qRound(x[0]), qRound(y[0]),
                qRound(x[1]), qRound(y[1]),
                qRound(x[2]), qRound(y[2]),
                qRound(x[3]), qRound(y[3]));
    return a;
}

/*!
    Creates a transformation matrix, \a trans, that maps a unit square
    to a four-sided polygon, \a quad. Returns true if the transformation
    is constructed or false if such a transformation does not exist.

    \sa quadToSquare(), quadToQuad()
*/
bool QTransform::squareToQuad(const QPolygonF &quad, QTransform &trans)
{
    if (quad.count() != 4)
        return false;

    qreal dx0 = quad[0].x();
    qreal dx1 = quad[1].x();
    qreal dx2 = quad[2].x();
    qreal dx3 = quad[3].x();

    qreal dy0 = quad[0].y();
    qreal dy1 = quad[1].y();
    qreal dy2 = quad[2].y();
    qreal dy3 = quad[3].y();

    double ax  = dx0 - dx1 + dx2 - dx3;
    double ay  = dy0 - dy1 + dy2 - dy3;

    if (!ax && !ay) { //afine transform
        trans.setMatrix(dx1 - dx0, dy1 - dy0,  0,
                        dx2 - dx1, dy2 - dy1,  0,
                        dx0,       dy0,  1);
    } else {
        double ax1 = dx1 - dx2;
        double ax2 = dx3 - dx2;
        double ay1 = dy1 - dy2;
        double ay2 = dy3 - dy2;

        /*determinants */
        double gtop    =  ax  * ay2 - ax2 * ay;
        double htop    =  ax1 * ay  - ax  * ay1;
        double bottom  =  ax1 * ay2 - ax2 * ay1;

        double a, b, c, d, e, f, g, h;  /*i is always 1*/

        if (!bottom)
            return false;

        g = gtop/bottom;
        h = htop/bottom;

        a = dx1 - dx0 + g * dx1;
        b = dx3 - dx0 + h * dx3;
        c = dx0;
        d = dy1 - dy0 + g * dy1;
        e = dy3 - dy0 + h * dy3;
        f = dy0;

        trans.setMatrix(a, d, g,
                        b, e, h,
                        c, f, 1.0);
    }

    return true;
}

/*!
    \fn bool QTransform::quadToSquare(const QPolygonF &quad, QTransform &trans)
    
    Creates a transformation matrix, \a trans, that maps a four-sided polygon,
    \a quad, to a unit square. Returns true if the transformation is constructed
    or false if such a transformation does not exist. 

    \sa squareToQuad(), quadToQuad()
*/
bool QTransform::quadToSquare(const QPolygonF &quad, QTransform &trans)
{
    if (!squareToQuad(quad, trans))
        return false;

    bool invertible = false;
    trans = trans.inverted(&invertible);

    return invertible;
}

/*!
    Creates a transformation matrix, \a trans, that maps a four-sided
    polygon, \a one, to another four-sided polygon, \a two.
    Returns true if the transformation is possible; otherwise returns
    false.

    This is a convenience method combining quadToSquare() and
    squareToQuad() methods. It allows the input quad to be
    transformed into any other quad.

    \sa squareToQuad(), quadToSquare()
*/
bool QTransform::quadToQuad(const QPolygonF &one,
                            const QPolygonF &two,
                            QTransform &trans)
{
    QTransform stq;
    if (!quadToSquare(one, trans))
        return false;
    if (!squareToQuad(two, stq))
        return false;
    trans *= stq;
    //qDebug()<<"Final = "<<trans;
    return true;
}

/*! 
    Sets the matrix elements to the specified values, \a m11,
    \a m12, \a m13 \a m21, \a m22, \a m23 \a m31, \a m32 and
    \a m33. Note that this function replaces the previous values. 
    QMatrix provides the translate(), rotate(), scale() and shear()
    convenience functions to manipulate the various matrix elements
    based on the currently defined coordinate system. 
    
    \sa QTransform()
*/

void QTransform::setMatrix(qreal m11, qreal m12, qreal m13,
                           qreal m21, qreal m22, qreal m23,
                           qreal m31, qreal m32, qreal m33)
{
    affine._m11 = m11; affine._m12 = m12; m_13 = m13;
    affine._m21 = m21; affine._m22 = m22; m_23 = m23;
    affine._dx = m31; affine._dy = m32; m_33 = m33;
    m_type = TxNone;
    m_dirty = TxProject;
}

QRect QTransform::mapRect(const QRect &rect) const
{
    QRect result;
    if (isAffine() && !isRotating()) {
        int x = qRound(affine._m11*rect.x() + affine._dx);
        int y = qRound(affine._m22*rect.y() + affine._dy);
        int w = qRound(affine._m11*rect.width());
        int h = qRound(affine._m22*rect.height());
        if (w < 0) {
            w = -w;
            x -= w;
        }
        if (h < 0) {
            h = -h;
            y -= h;
        }
        result = QRect(x, y, w, h);
    } else {
        // see mapToPolygon for explanations of the algorithm.
        qreal x0, y0;
        qreal x, y, fx, fy;
        MAPDOUBLE(rect.left(), rect.top(), x0, y0);
        qreal xmin = x0;
        qreal ymin = y0;
        qreal xmax = x0;
        qreal ymax = y0;
        MAPDOUBLE(rect.right() + 1, rect.top(), x, y);
        xmin = qMin(xmin, x);
        ymin = qMin(ymin, y);
        xmax = qMax(xmax, x);
        ymax = qMax(ymax, y);
        MAPDOUBLE(rect.right() + 1, rect.bottom() + 1, x, y);
        xmin = qMin(xmin, x);
        ymin = qMin(ymin, y);
        xmax = qMax(xmax, x);
        ymax = qMax(ymax, y);
        MAPDOUBLE(rect.left(), rect.bottom() + 1, x, y);
        xmin = qMin(xmin, x);
        ymin = qMin(ymin, y);
        xmax = qMax(xmax, x);
        ymax = qMax(ymax, y);
        qreal w = xmax - xmin;
        qreal h = ymax - ymin;
        xmin -= (xmin - x0) / w;
        ymin -= (ymin - y0) / h;
        xmax -= (xmax - x0) / w;
        ymax -= (ymax - y0) / h;
        result = QRect(qRound(xmin), qRound(ymin),
                       qRound(xmax)-qRound(xmin)+1, qRound(ymax)-qRound(ymin)+1);
    }
    return result;
}

/*!
    \fn QRectF QTransform::mapRect(const QRectF &rectangle) const

    Creates and returns a QRectF object that is a copy 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
        if (is not affine) {
            w' = m13*x + m23*y + m33
            x' /= w'
            y' /= w'
        }
    \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(), {QTransform#Basic Matrix Operations}{Basic Matrix
    Operations}
*/
QRectF QTransform::mapRect(const QRectF &rect) const
{
      QRectF result;
    if (isAffine() && !isRotating()) {
        qreal x = affine._m11*rect.x() + affine._dx;
        qreal y = affine._m22*rect.y() + affine._dy;
        qreal w = affine._m11*rect.width();
        qreal h = affine._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, fx, fy;
        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 QTransform::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.
*/

/*!
    Maps the given coordinates \a x and \a y into the coordinate
    system defined by this matrix. The resulting values are put in *\a
    tx and *\a ty, respectively.

    The coordinates are transformed using the following formulas:

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

    The point (x, y) is the original point, and (x', y') is the
    transformed point.

    \sa {QTransform#Basic Matrix Operations}{Basic Matrix Operations}
*/
void QTransform::map(qreal x, qreal y, qreal *tx, qreal *ty) const
{
    qreal fx, fy;
    MAPDOUBLE(x, y, *tx, *ty);
}

/*!
    \overload

    Maps the given coordinates \a x and \a y into the coordinate
    system defined by this matrix. The resulting values are put in *\a
    tx and *\a ty, respectively. Note that the transformed coordinates
    are rounded to the nearest integer.
*/
void QTransform::map(int x, int y, int *tx, int *ty) const
{
    int fx, fy;
    MAPINT(x, y, *tx, *ty);
}

/*!
  Returns the QTransform cast to a QMatrix.
 */
const QMatrix &QTransform::toAffine() const
{
    return affine;
}

/*!
  Returns the transformation type of this matrix.
  */
QTransform::TransformationType QTransform::type() const
{
    if (m_dirty != TxNone && m_dirty >= m_type) {
        if (m_dirty > TxShear && (!qFuzzyCompare(m_13, 0) || !qFuzzyCompare(m_23, 0)))
             m_type = TxProject;
        else if (m_dirty > TxScale && (!qFuzzyCompare(affine._m12, 0) || !qFuzzyCompare(affine._m21, 0))) {
            const qreal dot = affine._m11 * affine._m12 + affine._m21 * affine._m22;
            if (qFuzzyCompare(dot, 0))
                m_type = TxRotate;
            else
                m_type = TxShear;
        } else if (m_dirty > TxTranslate && (!qFuzzyCompare(affine._m11, 1) || !qFuzzyCompare(affine._m22, 1) || !qFuzzyCompare(m_33, 1)))
            m_type = TxScale;
        else if (m_dirty > TxNone && (!qFuzzyCompare(affine._dx, 0) || !qFuzzyCompare(affine._dy, 0)))
            m_type = TxTranslate;
        else
            m_type = TxNone;

        m_dirty = TxNone;
    }

    return static_cast<TransformationType>(m_type);
}

/*!

    Returns the transform as a QVariant.
*/
QTransform::operator QVariant() const
{
    return QVariant(QVariant::Transform, this);
}


/*!
    \fn bool QTransform::isInvertible() const

    Returns true if the matrix is invertible, otherwise returns false.

    \sa inverted()
*/

/*!
    \fn qreal QTransform::det() const

    Returns the matrix's determinant.
*/


/*!
    \fn qreal QTransform::m11() const

    Returns the horizontal scaling factor.

    \sa scale(), {QTransform#Basic Matrix Operations}{Basic Matrix
    Operations}
*/

/*!
    \fn qreal QTransform::m12() const

    Returns the vertical shearing factor.

    \sa shear(), {QTransform#Basic Matrix Operations}{Basic Matrix
    Operations}
*/

/*!
    \fn qreal QTransform::m21() const

    Returns the horizontal shearing factor.

    \sa shear(), {QTransform#Basic Matrix Operations}{Basic Matrix
    Operations}
*/

/*!
    \fn qreal QTransform::m22() const

    Returns the vertical scaling factor.

    \sa scale(), {QTransform#Basic Matrix Operations}{Basic Matrix
    Operations}
*/

/*!
    \fn qreal QTransform::dx() const

    Returns the horizontal translation factor.

    \sa m31(), translate(), {QTransform#Basic Matrix Operations}{Basic Matrix
    Operations}
*/

/*!
    \fn qreal QTransform::dy() const

    Returns the vertical translation factor.

    \sa translate(), {QTransform#Basic Matrix Operations}{Basic Matrix
    Operations}
*/


/*!
    \fn qreal QTransform::m13() const

    Returns the horizontal projection factor.

    \sa translate(), {QTransform#Basic Matrix Operations}{Basic Matrix
    Operations}
*/


/*!
    \fn qreal QTransform::m23() const

    Returns the vertical projection factor.

    \sa translate(), {QTransform#Basic Matrix Operations}{Basic Matrix
    Operations}
*/

/*!
    \fn qreal QTransform::m31() const

    Returns the horizontal translation factor.

    \sa dx(), translate(), {QTransform#Basic Matrix Operations}{Basic Matrix
    Operations}
*/

/*!
    \fn qreal QTransform::m32() const

    Returns the vertical translation factor.

    \sa dy(), translate(), {QTransform#Basic Matrix Operations}{Basic Matrix
    Operations}
*/

/*!
    \fn qreal QTransform::m33() const

    Returns the division factor.

    \sa translate(), {QTransform#Basic Matrix Operations}{Basic Matrix
    Operations}
*/

/*!
    \fn qreal QTransform::determinant() const

    Returns the matrix's determinant.
*/

/*!
    \fn bool QTransform::isIdentity() const

    Returns true if the matrix is the identity matrix, otherwise
    returns false.

    \sa reset()
*/

/*!
    \fn bool QTransform::isAffine() const

    Returns true if the matrix represent an affine transformation,
    otherwise returns false.
*/

/*!
    \fn bool QTransform::isScaling() const

    Returns true if the matrix represents a scaling
    transformation, otherwise returns false.

    \sa reset()
*/

/*!
    \fn bool QTransform::isRotating() const

    Returns true if the matrix represents some kind of a
    scaling transformation, otherwise returns false.

    \sa reset()
*/

/*!
    \fn bool QTransform::isTranslating() const

    Returns true if the matrix represents a translating
    transformation, otherwise returns false.

    \sa reset()
*/