ugklinestring.cpp

linux下一款GIS程序源码

// ugklinestring.cpp: implementation of the UGKLineString class.
//
//////////////////////////////////////////////////////////////////////

#include "ugklinestring.h"

#include "ugk_memopr.h"

/************************************************************************/
/*                           UGKLineString()                            */
/************************************************************************/
UGKLineString::UGKLineString()
{
	nPointCount = 0;
	paoPoints = NULL;
	padfZ = NULL;

}

/************************************************************************/
/*                           ~UGKLineString()                           */
/************************************************************************/
UGKLineString::~UGKLineString()
{
	if ( paoPoints != NULL)
		UGK_Free(paoPoints);
	if( padfZ != NULL )
		UGK_Free(padfZ);
}


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

const char * UGKLineString::getGeometryName() const

{
    return "LINESTRING";
}

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

UGKwkbGeometryType UGKLineString::getGeometryType() const

{
    if( getCoordinateDimension() == 3 )
        return wkbLineString25D;
    else
        return wkbLineString;
}


/************************************************************************/
/*                       getCoordinateDimension()                       */
/************************************************************************/

int UGKLineString::getCoordinateDimension() const

{
    if( padfZ != NULL )
        return 3;
    else
        return 2;
}

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

int UGKLineString::getDimension() const

{
    return 1;  //一维
}


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

void UGKLineString::empty()

{
    setNumPoints( 0 );
}


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

void UGKLineString::flattenTo2D()

{
    Make2D();
}


/************************************************************************/
/*                               Make2D()                               */
/*                              强制转换为2D                            */
/************************************************************************/

void UGKLineString::Make2D()

{
    if( padfZ != NULL )
    {
        UGK_Free( padfZ );
        padfZ = NULL;
    }
}


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

UGKGeometry *UGKLineString::clone() const

{
    UGKLineString       *poNewLineString;

    poNewLineString = new UGKLineString(); 

    poNewLineString->setPoints( nPointCount, paoPoints, padfZ );

 
    return poNewLineString;
}


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

int UGKLineString::WkbSize() const

{
    return 5 + 4 + 8 * nPointCount * getCoordinateDimension();
}


/************************************************************************/
/*                               Make3D()                               */
/*                            强制转换为3维                             */
/************************************************************************/

void UGKLineString::Make3D()

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

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

/**
 * Fetch a point in line string.
 */

void  UGKLineString::getPoint( int i, UGKPoint * poPoint ) const

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

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

    if( getCoordinateDimension() == 3 ) //如果是三维
        poPoint->setZ( padfZ[i] );
}



/************************************************************************/
/*                                getZ()                                */
/*                            返回指定点的Z坐标                         */
/************************************************************************/

double UGKLineString::getZ( int i ) const

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


/************************************************************************/
/*                            setNumPoints()                            */
/*                           设置曲线的顶点数                           */
/************************************************************************/

/**
 * 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(). 
 */


void UGKLineString::setNumPoints( int nNewPointCount )

{
    if( nNewPointCount == 0 ) //置0
    {
        UGK_Free( paoPoints );
        paoPoints = NULL;
        
        UGK_Free( padfZ );
        padfZ = NULL;
        
        nPointCount = 0;
        return;
    }
  //如果比当前已有的顶点数少，则不做任何操作
    if( nNewPointCount > nPointCount ) 
    {
        paoPoints = (UGKRawPoint *)
            UGK_Realloc(paoPoints, sizeof(UGKRawPoint) * nNewPointCount);

        assert( paoPoints != NULL );
        
        memset( paoPoints + nPointCount,         
                0, sizeof(UGKRawPoint) * (nNewPointCount - nPointCount) );
        // 对于新增加的顶点的值赋初值0
        if( getCoordinateDimension() == 3 )
        {
            padfZ = (double *)
                UGK_Realloc( 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.
 *
 */

void UGKLineString::setPoint( int iPoint, UGKPoint * 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.
 * 
 *
 * @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 UGKLineString::setPoint( int iPoint, double xIn, double yIn, double zIn )

{
    if( iPoint >= nPointCount ) //如果超过当前已有的顶点数
        setNumPoints( iPoint+1 );

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

    if( zIn != 0.0 )
    {//-----------如果原来所有的点都是二维的，而这里设置点的Z坐标不为0------
        Make3D();  //强制转换为3维
        padfZ[iPoint] = zIn;
    }
    else if( getCoordinateDimension() == 3 )
    {
        padfZ[iPoint] = 0.0;
    }
}



/************************************************************************/
/*                              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.
 */

void UGKLineString::addPoint( UGKPoint * 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.
 * @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 UGKLineString::addPoint( double x, double y, double z )

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

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

/**
 * Assign all points in a line string.
 * //注意：这个方法会清除所有已经存在的顶点
 * 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.
 *
 * @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).
 */