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qt5-legatus-legacy/Lts/Viewer/SituationMap/MathUtils/path_rasterer.cpp
T
2026-08-13 18:33:10 +02:00

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C++
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/**
**
** @RDE_HEADER@
** Rasterize functional path geometries to polylines
** $Id$
** $HeadURL$
** $Author$
**
** -----------------------------------------------------------------------------------------------
**
** Hardware-Environment: Intel-PC
** Software-Environment: Windows 7, Qt 5.4. ArcGIS 10.2.5
**
** Language ........: C++ 11
**
** -----------------------------------------------------------------------------------------------
**
** Author ...........: Jörg Turla, SPD G, Tel. 3132
**
** -----------------------------------------------------------------------------------------------
**
** Notes .........:
**
** 12.08.2015, JT : First edition for use with Qt5
**
** -----------------------------------------------------------------------------------------------
*/
#include "path_rasterer.h"
#include <cmath>
namespace SituationMap { namespace MathUtils
{
PathRasterer::PathRasterer() : _eps(1.0), _maxVertexCount(0)
{
} /* PathRasterer::PathRasterer */
void PathRasterer::rasterize(qreal tMin, qreal tMax, QVector<QPointF> & vertexList) { exeRasterize( tMin, tMax, vertexList ); }
void PathRasterer::rasterize(qreal tMin, qreal tMax, QList<QPointF> & vertexList) { exeRasterize( tMin, tMax, vertexList ); }
template <class List> void PathRasterer::exeRasterize( qreal tMin, qreal tMax, List & vertexList )
{
vertexList.clear();
if (tMin >= tMax) return;
QPointF vMin, vMax;
function( tMax, vMax );
function( tMin, vMin );
vertexList.append(vMin);
splitSegment( vMin, tMin, vMax, tMax, _maxVertexCount, vertexList );
vertexList.append(vMax);
} /* PathRasterer::exeRasterize */
template <class List> void PathRasterer::splitSegment( const QPointF & v0
, qreal t0
, const QPointF & v1
, qreal t1
, unsigned int maxVertexCount
, List & vertexList )
{
if (maxVertexCount < 1)
return;
QPointF v2;
qreal t2 = (t0+t1) * 0.5;
function( t2, v2 );
auto length = []( const QPointF & v ) -> qreal { return sqrt(v.x()*v.x() + v.y()*v.y()); };
qreal l0 = length(v1-v0);
qreal l1 = length(v1-v2);
qreal l2 = length(v2-v0);
/* -------------------------------------------------------------------------
* Berechnen der Höhe des Dreiecks über l0 für den Vergleich mit
* dem Schwellwert (siehe Kosinussatz, Trigonometrische Funktionen, etc.).
* ------------------------------------------------------------------------- */
qreal cosPhi = (l2*l2+l0*l0-l1*l1)/(2.0*l2*l0);
qreal h_eps = l2*sqrt(1.0-cosPhi*cosPhi);
// (maxVertexCount > 0) -> see pre-condition
if (((std::isnan(h_eps)) || (h_eps > _eps)))
{
maxVertexCount /= 2;
splitSegment( v0, t0, v2, t2, maxVertexCount, vertexList );
vertexList.append( v2 );
splitSegment( v2, t2, v1, t1, maxVertexCount, vertexList );
}
} /* PathRasterer::splitSegment */
} } // namespace SituationMap::MathUtils