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#9485: OffsetLine uses GEOSOffsetCurve

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ahuarte47 committed Feb 26, 2014
1 parent bcbf9dd commit 8176c1cde8a040e93dbdf3a93f033823006fd350
Showing with 38 additions and 0 deletions.
  1. +38 −0 src/core/symbology-ng/qgssymbollayerv2utils.cpp
@@ -653,6 +653,43 @@ QPolygonF offsetLine( QPolygonF polyline, double dist )
if ( polyline.count() < 2 )
return newLine;

// need at least geos 3.3 for OffsetCurve tool
#if defined(GEOS_VERSION_MAJOR) && defined(GEOS_VERSION_MINOR) && \
((GEOS_VERSION_MAJOR>3) || ((GEOS_VERSION_MAJOR==3) && (GEOS_VERSION_MINOR>=3)))

if ( polyline.count() > 2 )
{
unsigned int i, pointCount = polyline.count();

QgsPolyline tempPolyline( pointCount );
QPointF* tempPtr = polyline.data();
for ( i = 0; i < pointCount; ++i, tempPtr++ ) tempPolyline[i] = QgsPoint( tempPtr->rx(), tempPtr->ry() );

QgsGeometry* tempGeometry = QgsGeometry::fromPolyline( tempPolyline );
if ( tempGeometry )
{
const GEOSGeometry* geosGeom = tempGeometry->asGeos();
GEOSGeometry* offsetGeom = GEOSOffsetCurve( geosGeom, dist, 8 /*quadSegments*/, 0 /*joinStyle*/, 5.0 /*mitreLimit*/ );

if ( offsetGeom )
{
tempGeometry->fromGeos( offsetGeom );
tempPolyline = tempGeometry->asPolyline();

pointCount = tempPolyline.count();
newLine.resize( pointCount );

QgsPoint* tempPtr2 = tempPolyline.data();
for ( i = 0; i < pointCount; ++i, tempPtr2++ ) newLine[i] = QPointF( tempPtr2->x(), tempPtr2->y() );

delete tempGeometry;
return newLine;
}
delete tempGeometry;
}
}
#endif

double angle = 0.0, t_new, t_old = 0;
QPointF pt_old, pt_new;
QPointF p1 = polyline[0], p2;
@@ -687,6 +724,7 @@ QPolygonF offsetLine( QPolygonF polyline, double dist )
// last line segment:
pt_new = offsetPoint( p2, angle + M_PI / 2, dist );
newLine.append( pt_new );

return newLine;
}

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