Package org.locationtech.jts.noding.snapround

Class HotPixel

  • public class HotPixel
extends Object
    Implements a "hot pixel" as used in the Snap Rounding algorithm. A hot pixel is a square region centred on the rounded valud of the coordinate given, and of width equal to the size of the scale factor. It is a partially open region, which contains the interior of the tolerance square and the boundary minus the top and right segments. This ensures that every point of the space lies in a unique hot pixel. It also matches the rounding semantics for numbers.

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

    Hot Pixels support being marked as nodes. This is used to prevent introducing nodes at line vertices which do not have other lines snapped to them.

    Version:
    1.7

    • Constructor Detail

      • HotPixel

        public HotPixel​(Coordinate pt,
                double scaleFactor)
        Creates a new hot pixel centered on a rounded point, using a given scale factor. The scale factor must be strictly positive (non-zero).
        Parameters:
        pt - the coordinate at the centre of the pixel (already rounded)
        scaleFactor - the scaleFactor determining the pixel size. Must be > 0

    • Method Detail

      • getCoordinate

        public Coordinate getCoordinate()
        Gets the coordinate this hot pixel is based at.
        Returns:
        the coordinate of the pixel

      • getScaleFactor

        public double getScaleFactor()
        Gets the scale factor for the precision grid for this pixel.
        Returns:
        the pixel scale factor

      • getWidth

        public double getWidth()
        Gets the width of the hot pixel in the original coordinate system.
        Returns:
        the width of the hot pixel tolerance square

      • isNode

        public boolean isNode()
        Tests whether this pixel has been marked as a node.
        Returns:
        true if the pixel is marked as a node

      • setToNode

        public void setToNode()
        Sets this pixel to be a node.

      • intersects

        public boolean intersects​(Coordinate p)
        Tests whether a coordinate lies in (intersects) this hot pixel.
        Parameters:
        p - the coordinate to test
        Returns:
        true if the coordinate intersects this hot pixel

      • intersects

        public boolean intersects​(Coordinate p0,
                          Coordinate p1)
        Tests whether the line segment (p0-p1) intersects this hot pixel.
        Parameters:
        p0 - the first coordinate of the line segment to test
        p1 - the second coordinate of the line segment to test
        Returns:
        true if the line segment intersects this hot pixel