ogrpolygon.cpp

mitab,读取MapInfo的地图文件

/******************************************************************************
 * $Id: ogrpolygon.cpp 11427 2007-05-07 19:16:26Z warmerdam $
 *
 * Project:  OpenGIS Simple Features Reference Implementation
 * Purpose:  The OGRPolygon geometry class.
 * Author:   Frank Warmerdam, [e-mail]
 *
 ******************************************************************************
 * Copyright (c) 1999, Frank Warmerdam
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 ****************************************************************************/

#include "ogr_geometry.h"
#include "ogr_p.h"
#include "ogr_geos.h"
#include "ogr_api.h"

CPL_CVSID("$Id: ogrpolygon.cpp 11427 2007-05-07 19:16:26Z warmerdam $");

/************************************************************************/
/*                             OGRPolygon()                             */
/************************************************************************/

/**
 * Create an empty polygon.
 */

OGRPolygon::OGRPolygon()

{
    nRingCount = 0;
    papoRings = NULL;
}

/************************************************************************/
/*                            ~OGRPolygon()                             */
/************************************************************************/

OGRPolygon::~OGRPolygon()

{
    empty();
}

/************************************************************************/
/*                               clone()                                */
/************************************************************************/

OGRGeometry *OGRPolygon::clone() const

{
    OGRPolygon  *poNewPolygon;

    poNewPolygon = new OGRPolygon;
    poNewPolygon->assignSpatialReference( getSpatialReference() );

    for( int i = 0; i < nRingCount; i++ )
    {
        poNewPolygon->addRing( papoRings[i] );
    }

    return poNewPolygon;
}

/************************************************************************/
/*                               empty()                                */
/************************************************************************/

void OGRPolygon::empty()

{
    if( papoRings != NULL )
    {
        for( int i = 0; i < nRingCount; i++ )
        {
            delete papoRings[i];
        }
        OGRFree( papoRings );
    }

    papoRings = NULL;
    nRingCount = 0;
}

/************************************************************************/
/*                          getGeometryType()                           */
/************************************************************************/

OGRwkbGeometryType OGRPolygon::getGeometryType() const

{
    if( getCoordinateDimension() == 3 )
        return wkbPolygon25D;
    else
        return wkbPolygon;
}

/************************************************************************/
/*                            getDimension()                            */
/************************************************************************/

int OGRPolygon::getDimension() const

{
    return 2;
}

/************************************************************************/
/*                            flattenTo2D()                             */
/************************************************************************/

void OGRPolygon::flattenTo2D()

{
    for( int iRing = 0; iRing < nRingCount; iRing++ )
        papoRings[iRing]->flattenTo2D();

    nCoordDimension = 2;
}

/************************************************************************/
/*                          getGeometryName()                           */
/************************************************************************/

const char * OGRPolygon::getGeometryName() const

{
    return "POLYGON";
}

/************************************************************************/
/*                          getExteriorRing()                           */
/************************************************************************/

/**
 * Fetch reference to external polygon ring.
 *
 * Note that the returned ring pointer is to an internal data object of
 * the OGRPolygon.  It should not be modified or deleted by the application,
 * and the pointer is only valid till the polygon is next modified.  Use
 * the OGRGeometry::clone() method to make a separate copy within the
 * application.
 *
 * Relates to the SFCOM IPolygon::get_ExteriorRing() method.
 *
 * @return pointer to external ring.  May be NULL if the OGRPolygon is empty.
 */

OGRLinearRing *OGRPolygon::getExteriorRing()

{
    if( nRingCount > 0 )
        return papoRings[0];
    else
        return NULL;
}

const OGRLinearRing *OGRPolygon::getExteriorRing() const

{
    if( nRingCount > 0 )
        return papoRings[0];
    else
        return NULL;
}

/************************************************************************/
/*                        getNumInteriorRings()                         */
/************************************************************************/

/**
 * Fetch the number of internal rings.
 *
 * Relates to the SFCOM IPolygon::get_NumInteriorRings() method.
 *
 * @return count of internal rings, zero or more.
 */


int OGRPolygon::getNumInteriorRings() const

{
    if( nRingCount > 0 )
        return nRingCount-1;
    else
        return 0;
}

/************************************************************************/
/*                          getInteriorRing()                           */
/************************************************************************/

/**
 * Fetch reference to indicated internal ring.
 *
 * Note that the returned ring pointer is to an internal data object of
 * the OGRPolygon.  It should not be modified or deleted by the application,
 * and the pointer is only valid till the polygon is next modified.  Use
 * the OGRGeometry::clone() method to make a separate copy within the
 * application.
 *
 * Relates to the SFCOM IPolygon::get_InternalRing() method.
 *
 * @param iRing internal ring index from 0 to getNumInternalRings() - 1.
 *
 * @return pointer to external ring.  May be NULL if the OGRPolygon is empty.
 */

OGRLinearRing *OGRPolygon::getInteriorRing( int iRing )

{
    if( iRing < 0 || iRing >= nRingCount-1 )
        return NULL;
    else
        return papoRings[iRing+1];
}

const OGRLinearRing *OGRPolygon::getInteriorRing( int iRing ) const

{
    if( iRing < 0 || iRing >= nRingCount-1 )
        return NULL;
    else
        return papoRings[iRing+1];
}

/************************************************************************/
/*                              addRing()                               */
/************************************************************************/

/**
 * Add a ring to a polygon.
 *
 * If the polygon has no external ring (it is empty) this will be used as
 * the external ring, otherwise it is used as an internal ring.  The passed
 * OGRLinearRing remains the responsibility of the caller (an internal copy
 * is made).
 *
 * This method has no SFCOM analog.
 *
 * @param poNewRing ring to be added to the polygon.
 */

void OGRPolygon::addRing( OGRLinearRing * poNewRing )

{
    papoRings = (OGRLinearRing **) OGRRealloc( papoRings,
                                               sizeof(void*) * (nRingCount+1));

    papoRings[nRingCount] = new OGRLinearRing( poNewRing );

    nRingCount++;

    if( poNewRing->getCoordinateDimension() == 3 )
        nCoordDimension = 3;
}

/************************************************************************/
/*                          addRingDirectly()                           */
/************************************************************************/

/**
 * Add a ring to a polygon.
 *
 * If the polygon has no external ring (it is empty) this will be used as
 * the external ring, otherwise it is used as an internal ring.  Ownership
 * of the passed ring is assumed by the OGRPolygon, but otherwise this
 * method operates the same as OGRPolygon::AddRing().
 *
 * This method has no SFCOM analog.
 *
 * @param poNewRing ring to be added to the polygon.
 */

void OGRPolygon::addRingDirectly( OGRLinearRing * poNewRing )

{
    papoRings = (OGRLinearRing **) OGRRealloc( papoRings,
                                               sizeof(void*) * (nRingCount+1));

    papoRings[nRingCount] = poNewRing;

    nRingCount++;


    if( poNewRing->getCoordinateDimension() == 3 )
        nCoordDimension = 3;
}

/************************************************************************/
/*                              WkbSize()                               */
/*                                                                      */
/*      Return the size of this object in well known binary             */
/*      representation including the byte order, and type information.  */
/************************************************************************/

int OGRPolygon::WkbSize() const

{
    int         nSize = 9;
    int         b3D = getCoordinateDimension() == 3;

    for( int i = 0; i < nRingCount; i++ )
    {
        nSize += papoRings[i]->_WkbSize( b3D );
    }

    return nSize;
}