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**
** This file is part of the painting module of the Qt Toolkit.
**
** This file may be distributed and/or modified under the terms of the
** GNU General Public License version 2 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.
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** information about Qt Commercial License Agreements.
** See http://www.trolltech.com/gpl/ for GPL licensing information.
**
** Contact info@trolltech.com if any conditions of this licensing are
** not clear to you.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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****************************************************************************/

#include "qregion.h"
#include "qpolygon.h"
#include "qbuffer.h"
#include "qdatastream.h"
#include "qvariant.h"

#include <qdebug.h>

/*!
    \class QRegion
    \brief The QRegion class specifies a clip region for a painter.

    \ingroup multimedia

    QRegion is used with QPainter::setClipRegion() to limit the paint
    area to what needs to be painted. There is also a
    QWidget::repaint() function that takes a QRegion parameter.
    QRegion is the best tool for reducing flicker.

    A region can be created from a rectangle, an ellipse, a polygon or
    a bitmap. Complex regions may be created by combining simple
    regions using unite(), intersect(), subtract(), or eor() (exclusive
    or). You can move a region using translate().

    You can test whether a region isEmpty() or if it
    contains() a QPoint or QRect. The bounding rectangle can be found
    with boundingRect().

    The function rects() gives a decomposition of the region into
    rectangles.

    Example of using complex regions:
    \code
        void MyWidget::paintEvent(QPaintEvent *)
        {
            QPainter p;                       // our painter
            QRegion r1(QRect(100,100,200,80), // r1 = elliptic region
                       QRegion::Ellipse);
            QRegion r2(QRect(100,120,90,30)); // r2 = rectangular region
            QRegion r3 = r1.intersect(r2);    // r3 = intersection
            p.begin(this);                    // start painting widget
            p.setClipRegion(r3);              // set clip region
            ...                               // paint clipped graphics
            p.end();                          // painting done
        }
    \endcode

    QRegion is an \link shclass.html implicitly shared\endlink class.

    \warning Due to window system limitations, the whole coordinate space for a
    region is limited to the points between -32767 and 32767 on Windows
    95/98/ME. You can circumvent this limitation by using a QPainterPath.

    \sa QPainter::setClipRegion(), QPainter::setClipRect()

    \sa QPainterPath
*/


/*!
    \enum QRegion::RegionType

    Specifies the shape of the region to be created.

    \value Rectangle  the region covers the entire rectangle.
    \value Ellipse  the region is an ellipse inside the rectangle.
*/

/*!
    \fn void QRegion::translate(const QPoint &point)

    \overload

    Translates to the given \a point.
*/

/*!
    \fn Handle QRegion::handle() const

    Returns a platform-specific region handle. The \c Handle type is
    \c HRGN on Windows, \c Region on X11, and \c RgnHandle on Mac OS
    X.

    \warning This function is not portable.
*/

/*****************************************************************************
  QRegion member functions
 *****************************************************************************/

/*!
    Constructs a rectangular or elliptic region.

    If \a t is \c Rectangle, the region is the filled rectangle (\a x,
    \a y, \a w, \a h). If \a t is \c Ellipse, the region is the filled
    ellipse with center at (\a x + \a w / 2, \a y + \a h / 2) and size
    (\a w ,\a h).
*/
QRegion::QRegion(int x, int y, int w, int h, RegionType t)
{
    QRegion tmp(QRect(x, y, w, h), t);
    tmp.d->ref.ref();
    d = tmp.d;
}

#ifdef QT3_SUPPORT
/*!
    Use the constructor tha takes a Qt::FillRule as the second
    argument instead.
*/
QRegion::QRegion(const QPolygon &pa, bool winding)
{
    new (this) QRegion(pa, winding ? Qt::WindingFill : Qt::OddEvenFill);
}
#endif

/*!
    Detaches from shared region data to make sure that this region is
    the only one referring to the data.

    \sa copy(), \link shclass.html shared classes\endlink
*/

void QRegion::detach()
{
    if (d->ref != 1)
        *this = copy();
}

// duplicates in qregion_win.cpp and qregion_wce.cpp
#define QRGN_SETRECT          1                // region stream commands
#define QRGN_SETELLIPSE       2                //  (these are internal)
#define QRGN_SETPTARRAY_ALT   3
#define QRGN_SETPTARRAY_WIND  4
#define QRGN_TRANSLATE        5
#define QRGN_OR               6
#define QRGN_AND              7
#define QRGN_SUB              8
#define QRGN_XOR              9
#define QRGN_RECTS            10


#ifndef QT_NO_DATASTREAM
/*
    Executes region commands in the internal buffer and rebuilds the
    original region.

    We do this when we read a region from the data stream.

    If \a ver is non-0, uses the format version \a ver on reading the
    byte array.
*/

void QRegion::exec(const QByteArray &buffer, int ver)
{
    QByteArray copy = buffer;
    QDataStream s(&copy, QIODevice::ReadOnly);
    if (ver)
        s.setVersion(ver);
    QRegion rgn;
#ifndef QT_NO_DEBUG
    int test_cnt = 0;
#endif
    while (!s.atEnd()) {
        qint32 id;
        if (s.version() == 1) {
            int id_int;
            s >> id_int;
            id = id_int;
        } else {
            s >> id;
        }
#ifndef QT_NO_DEBUG
        if (test_cnt > 0 && id != QRGN_TRANSLATE)
            qWarning("QRegion::exec: Internal error");
        test_cnt++;
#endif
        if (id == QRGN_SETRECT || id == QRGN_SETELLIPSE) {
            QRect r;
            s >> r;
            rgn = QRegion(r, id == QRGN_SETRECT ? Rectangle : Ellipse);
        } else if (id == QRGN_SETPTARRAY_ALT || id == QRGN_SETPTARRAY_WIND) {
            QPolygon a;
            s >> a;
            rgn = QRegion(a, id == QRGN_SETPTARRAY_WIND ? Qt::WindingFill : Qt::OddEvenFill);
        } else if (id == QRGN_TRANSLATE) {
            QPoint p;
            s >> p;
            rgn.translate(p.x(), p.y());
        } else if (id >= QRGN_OR && id <= QRGN_XOR) {
            QByteArray bop1, bop2;
            QRegion r1, r2;
            s >> bop1;
            r1.exec(bop1);
            s >> bop2;
            r2.exec(bop2);

            switch (id) {
                case QRGN_OR:
                    rgn = r1.unite(r2);
                    break;
                case QRGN_AND:
                    rgn = r1.intersect(r2);
                    break;
                case QRGN_SUB:
                    rgn = r1.subtract(r2);
                    break;
                case QRGN_XOR:
                    rgn = r1.eor(r2);
                    break;
            }
        } else if (id == QRGN_RECTS) {
            // (This is the only form used in Qt 2.0)
            quint32 n;
            s >> n;
            QRect r;
            for (int i=0; i<(int)n; i++) {
                s >> r;
                rgn = rgn.unite(QRegion(r));
            }
        }
    }
    *this = rgn;
}


/*****************************************************************************
  QRegion stream functions
 *****************************************************************************/

/*!
    \relates QRegion

    Writes the region \a r to the stream \a s and returns a reference
    to the stream.

    \sa \link datastreamformat.html Format of the QDataStream operators \endlink
*/

QDataStream &operator<<(QDataStream &s, const QRegion &r)
{
    QVector<QRect> a = r.rects();
    if (a.isEmpty()) {
        s << (quint32)0;
    } else {
        if (s.version() == 1) {
            int i;
            for (i = a.size() - 1; i > 0; --i) {
                s << (quint32)(12 + i * 24);
                s << (int)QRGN_OR;
            }
            for (i = 0; i < a.size(); ++i) {
                s << (quint32)(4+8) << (int)QRGN_SETRECT << a[i];
            }
        } else {
            s << (quint32)(4 + 4 + 16 * a.size()); // 16: storage size of QRect
            s << (qint32)QRGN_RECTS;
            s << a;
        }
    }
    return s;
}

/*!
    \relates QRegion

    Reads a region from the stream \a s into \a r and returns a
    reference to the stream.

    \sa \link datastreamformat.html Format of the QDataStream operators \endlink
*/

QDataStream &operator>>(QDataStream &s, QRegion &r)
{
    QByteArray b;
    s >> b;
    r.exec(b, s.version());
    return s;
}
#endif //QT_NO_DATASTREAM

#ifndef QT_NO_DEBUG_STREAM
QDebug operator<<(QDebug s, const QRegion &r)
{
    QVector<QRect> rects = r.rects();
    s.nospace() << "QRegion(size=" << rects.size() << "), "
                << "bounds = " << r.boundingRect() << "\n";
    for (int i=0; i<rects.size(); ++i)
        s << "- " << i << rects.at(i) << "\n";
    return s;
}
#endif


// These are not inline - they can be implemented better on some platforms
//  (eg. Windows at least provides 3-variable operations).  For now, simple.


/*!
    Applies the unite() function to this region and \a r. \c r1|r2 is
    equivalent to \c r1.unite(r2)

    \sa unite(), operator+()
*/
const QRegion QRegion::operator|(const QRegion &r) const
    { return unite(r); }

/*!
    Applies the unite() function to this region and \a r. \c r1+r2 is
    equivalent to \c r1.unite(r2)

    \sa unite(), operator|()
*/
const QRegion QRegion::operator+(const QRegion &r) const
    { return unite(r); }

/*!
    Applies the intersect() function to this region and \a r. \c r1&r2
    is equivalent to \c r1.intersect(r2)

    \sa intersect()
*/
const QRegion QRegion::operator&(const QRegion &r) const
    { return intersect(r); }

/*!
    Applies the subtract() function to this region and \a r. \c r1-r2
    is equivalent to \c r1.subtract(r2)

    \sa subtract()
*/
const QRegion QRegion::operator-(const QRegion &r) const
    { return subtract(r); }

/*!
    Applies the eor() function to this region and \a r. \c r1^r2 is
    equivalent to \c r1.eor(r2)

    \sa eor()
*/
const QRegion QRegion::operator^(const QRegion &r) const
    { return eor(r); }

/*!
    Applies the unite() function to this region and \a r and assigns
    the result to this region. \c r1|=r2 is equivalent to \c
    r1=r1.unite(r2)

    \sa unite()
*/
QRegion& QRegion::operator|=(const QRegion &r)
    { return *this = *this | r; }

/*!
    Applies the unite() function to this region and \a r and assigns
    the result to this region. \c r1+=r2 is equivalent to \c
    r1=r1.unite(r2)

    \sa intersect()
*/
QRegion& QRegion::operator+=(const QRegion &r)
    { return *this = *this + r; }

/*!
    Applies the intersect() function to this region and \a r and
    assigns the result to this region. \c r1&=r2 is equivalent to \c
    r1=r1.intersect(r2)

    \sa intersect()
*/
QRegion& QRegion::operator&=(const QRegion &r)
    { return *this = *this & r; }

/*!
    Applies the subtract() function to this region and \a r and
    assigns the result to this region. \c r1-=r2 is equivalent to \c
    r1=r1.subtract(r2)

    \sa subtract()
*/
QRegion& QRegion::operator-=(const QRegion &r)
    { return *this = *this - r; }

/*!
    Applies the eor() function to this region and \a r and
    assigns the result to this region. \c r1^=r2 is equivalent to \c
    r1=r1.eor(r2)

    \sa eor()
*/
QRegion& QRegion::operator^=(const QRegion &r)
    { return *this = *this ^ r; }

/*!
    \fn bool QRegion::operator!=(const QRegion &other) const

    Returns true if this region is different from the \a other region;
    otherwise returns false.
*/

/*!
   Returns the region as a QVariant
*/
QRegion::operator QVariant() const
{
    return QVariant(QVariant::Region, this);
}

/*!
    \fn bool QRegion::isNull() const

    Use isEmpty() instead.
*/
