GEOS  3.8.0dev
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geos::noding::snapround::HotPixel Class Reference

Implements a "hot pixel" as used in the Snap Rounding algorithm. More...

#include <HotPixel.h>

Public Member Functions

 HotPixel (const geom::Coordinate &pt, double scaleFact, algorithm::LineIntersector &li)
 
const geom::CoordinategetCoordinate () const
 Return reference to original Coordinate (the one provided at construction time)
 
const geom::EnvelopegetSafeEnvelope () const
 Returns a "safe" envelope that is guaranteed to contain the hot pixel. Keeps ownership of it. More...
 
bool intersects (const geom::Coordinate &p0, const geom::Coordinate &p1) const
 
bool addSnappedNode (NodedSegmentString &segStr, std::size_t segIndex)
 

Detailed Description

Implements a "hot pixel" as used in the Snap Rounding algorithm.

A hot pixel contains the interior of the tolerance square and the boundary minus the top and right segments.

The hot pixel operations are all computed in the integer domain to avoid rounding problems.

Constructor & Destructor Documentation

geos::noding::snapround::HotPixel::HotPixel ( const geom::Coordinate pt,
double  scaleFact,
algorithm::LineIntersector li 
)

Creates a new hot pixel.

Parameters
ptthe coordinate at the centre of the pixel. Will be kept by reference, so make sure to keep it alive.
scaleFactthe scaleFactor determining the pixel size
lithe intersector to use for testing intersection with line segments

Member Function Documentation

bool geos::noding::snapround::HotPixel::addSnappedNode ( NodedSegmentString segStr,
std::size_t  segIndex 
)

Adds a new node (equal to the snap pt) to the specified segment if the segment passes through the hot pixel

Parameters
segStr
segIndex
Returns
true if a node was added to the segment
const geom::Envelope& geos::noding::snapround::HotPixel::getSafeEnvelope ( ) const

Returns a "safe" envelope that is guaranteed to contain the hot pixel. Keeps ownership of it.

The envelope returned will be larger than the exact envelope of the pixel.

bool geos::noding::snapround::HotPixel::intersects ( const geom::Coordinate p0,
const geom::Coordinate p1 
) const

Tests whether the line segment (p0-p1) intersects this hot pixel.

Parameters
p0the first coordinate of the line segment to test
p1the second coordinate of the line segment to test
Returns
true if the line segment intersects this hot pixel

The documentation for this class was generated from the following file: