ogrlinestring.cpp

用于读取TAB、MIF、SHP文件的类

{
    if( padfZ != NULL )
    {
        OGRFree( padfZ );
        padfZ = NULL;
    }
    nCoordDimension = 2;
}

/************************************************************************/
/*                               Make3D()                               */
/************************************************************************/

void OGRLineString::Make3D()

{
    if( padfZ == NULL )
    {
        if( nPointCount == 0 )
            padfZ = (double *) OGRCalloc(sizeof(double),1);
        else
            padfZ = (double *) OGRCalloc(sizeof(double),nPointCount);
    }
    nCoordDimension = 3;
}

/************************************************************************/
/*                              getPoint()                              */
/************************************************************************/

/**
 * Fetch a point in line string.
 *
 * This method relates to the SFCOM ILineString::get_Point() method.
 *
 * @param i the vertex to fetch, from 0 to getNumPoints()-1.
 * @param poPoint a point to initialize with the fetched point.
 */

void    OGRLineString::getPoint( int i, OGRPoint * poPoint ) const

{
    assert( i >= 0 );
    assert( i < nPointCount );
    assert( poPoint != NULL );

    poPoint->setX( paoPoints[i].x );
    poPoint->setY( paoPoints[i].y );

    if( getCoordinateDimension() == 3 && padfZ != NULL )
        poPoint->setZ( padfZ[i] );
}

/**
 * \fn int OGRLineString::getNumPoints() const;
 *
 * Fetch vertex count.
 *
 * Returns the number of vertices in the line string.  
 *
 * @return vertex count.
 */

/**
 * \fn double OGRLineString::getX( int iVertex ) const;
 *
 * Get X at vertex.
 *
 * Returns the X value at the indicated vertex.   If iVertex is out of range a
 * crash may occur, no internal range checking is performed.
 *
 * @param iVertex the vertex to return, between 0 and getNumPoints()-1. 
 *
 * @return X value.
 */

/**
 * \fn double OGRLineString::getY( int iVertex ) const;
 *
 * Get Y at vertex.
 *
 * Returns the Y value at the indicated vertex.   If iVertex is out of range a
 * crash may occur, no internal range checking is performed.
 *
 * @param iVertex the vertex to return, between 0 and getNumPoints()-1. 
 *
 * @return X value.
 */

/************************************************************************/
/*                                getZ()                                */
/************************************************************************/

/**
 * Get Z at vertex.
 *
 * Returns the Z (elevation) value at the indicated vertex.  If no Z
 * value is available, 0.0 is returned.  If iVertex is out of range a
 * crash may occur, no internal range checking is performed.
 *
 * @param iVertex the vertex to return, between 0 and getNumPoints()-1. 
 *
 * @return Z value.
 */

double OGRLineString::getZ( int iVertex ) const

{
    if( padfZ != NULL && iVertex >= 0 && iVertex < nPointCount 
        && nCoordDimension >= 3 )
        return( padfZ[iVertex] );
    else
        return 0.0;
}

/************************************************************************/
/*                            setNumPoints()                            */
/************************************************************************/

/**
 * Set number of points in geometry.
 *
 * This method primary exists to preset the number of points in a linestring
 * geometry before setPoint() is used to assign them to avoid reallocating
 * the array larger with each call to addPoint(). 
 *
 * This method has no SFCOM analog.
 *
 * @param nNewPointCount the new number of points for geometry.
 */

void OGRLineString::setNumPoints( int nNewPointCount )

{
    if( nNewPointCount == 0 )
    {
        OGRFree( paoPoints );
        paoPoints = NULL;
        
        OGRFree( padfZ );
        padfZ = NULL;
        
        nPointCount = 0;
        return;
    }

    if( nNewPointCount > nPointCount )
    {
        paoPoints = (OGRRawPoint *)
            OGRRealloc(paoPoints, sizeof(OGRRawPoint) * nNewPointCount);

        assert( paoPoints != NULL );
        
        memset( paoPoints + nPointCount,
                0, sizeof(OGRRawPoint) * (nNewPointCount - nPointCount) );
        
        if( getCoordinateDimension() == 3 )
        {
            padfZ = (double *)
                OGRRealloc( padfZ, sizeof(double)*nNewPointCount );
            memset( padfZ + nPointCount, 0,
                    sizeof(double) * (nNewPointCount - nPointCount) );
        }
    }

    nPointCount = nNewPointCount;
}

/************************************************************************/
/*                              setPoint()                              */
/************************************************************************/

/**
 * Set the location of a vertex in line string.
 *
 * If iPoint is larger than the number of necessary the number of existing
 * points in the line string, the point count will be increased to
 * accomodate the request.
 *
 * There is no SFCOM analog to this method.
 * 
 * @param iPoint the index of the vertex to assign (zero based).
 * @param poPoint the value to assign to the vertex.
 */

void OGRLineString::setPoint( int iPoint, OGRPoint * poPoint )

{
    setPoint( iPoint, poPoint->getX(), poPoint->getY(), poPoint->getZ() );
}

/************************************************************************/
/*                              setPoint()                              */
/************************************************************************/

/**
 * Set the location of a vertex in line string.
 *
 * If iPoint is larger than the number of necessary the number of existing
 * points in the line string, the point count will be increased to
 * accomodate the request.
 * 
 * There is no SFCOM analog to this method.
 *
 * @param iPoint the index of the vertex to assign (zero based).
 * @param xIn input X coordinate to assign.
 * @param yIn input Y coordinate to assign.
 * @param zIn input Z coordinate to assign (defaults to zero).
 */

void OGRLineString::setPoint( int iPoint, double xIn, double yIn, double zIn )

{
    if( getCoordinateDimension() == 2 )
        Make3D();

    if( iPoint >= nPointCount )
        setNumPoints( iPoint+1 );

    paoPoints[iPoint].x = xIn;
    paoPoints[iPoint].y = yIn;

    if( zIn != 0.0 )
    {
        Make3D();
        padfZ[iPoint] = zIn;
    }
    else if( getCoordinateDimension() == 3 )
    {
        padfZ[iPoint] = 0.0;
    }
}

void OGRLineString::setPoint( int iPoint, double xIn, double yIn )

{
    if( iPoint >= nPointCount )
        setNumPoints( iPoint+1 );

    paoPoints[iPoint].x = xIn;
    paoPoints[iPoint].y = yIn;
}

/************************************************************************/
/*                              addPoint()                              */
/************************************************************************/

/**
 * Add a point to a line string.
 *
 * The vertex count of the line string is increased by one, and assigned from
 * the passed location value.
 *
 * There is no SFCOM analog to this method.
 *
 * @param poPoint the point to assign to the new vertex.
 */

void OGRLineString::addPoint( OGRPoint * poPoint )

{
    setPoint( nPointCount, poPoint->getX(), poPoint->getY(), poPoint->getZ() );
}

/************************************************************************/
/*                              addPoint()                              */
/************************************************************************/

/**
 * Add a point to a line string.
 *
 * The vertex count of the line string is increased by one, and assigned from
 * the passed location value.
 *
 * There is no SFCOM analog to this method.
 *
 * @param x the X coordinate to assign to the new point.
 * @param y the Y coordinate to assign to the new point.
 * @param z the Z coordinate to assign to the new point (defaults to zero).
 */

void OGRLineString::addPoint( double x, double y, double z )

{
    setPoint( nPointCount, x, y, z );
}

void OGRLineString::addPoint( double x, double y )

{
    setPoint( nPointCount, x, y );
}

/************************************************************************/
/*                             setPoints()                              */
/************************************************************************/

/**
 * Assign all points in a line string.
 *
 * This method clears any existing points assigned to this line string,
 * and assigns a whole new set.  It is the most efficient way of assigning
 * the value of a line string.
 *
 * There is no SFCOM analog to this method.
 *
 * @param nPointsIn number of points being passed in paoPointsIn
 * @param paoPointsIn list of points being assigned.
 * @param padfZ the Z values that go with the points (optional, may be NULL).
 */

void OGRLineString::setPoints( int nPointsIn, OGRRawPoint * paoPointsIn,
                               double * padfZ )

{
    setNumPoints( nPointsIn );
    memcpy( paoPoints, paoPointsIn, sizeof(OGRRawPoint) * nPointsIn);

/* -------------------------------------------------------------------- */
/*      Check 2D/3D.                                                    */
/* -------------------------------------------------------------------- */
    if( padfZ == NULL && getCoordinateDimension() > 2 )
    {
        Make2D();
    }
    else if( padfZ )
    {
        Make3D();
        memcpy( this->padfZ, padfZ, sizeof(double) * nPointsIn );
    }
}

/************************************************************************/
/*                             setPoints()                              */
/************************************************************************/

/**
 * Assign all points in a line string.
 *
 * This method clear any existing points assigned to this line string,
 * and assigns a whole new set.
 *
 * There is no SFCOM analog to this method.
 *
 * @param nPointsIn number of points being passed in padfX and padfY.
 * @param padfX list of X coordinates of points being assigned.
 * @param padfY list of Y coordinates of points being assigned.
 * @param padfZ list of Z coordinates of points being assigned (defaults to
 * NULL for 2D objects).
 */

void OGRLineString::setPoints( int nPointsIn, double * padfX, double * padfY,
                               double * padfZ )

{
    int         i;

/* -------------------------------------------------------------------- */
/*      Check 2D/3D.                                                    */
/* -------------------------------------------------------------------- */