Class SnapRoundingNoder

  • All Implemented Interfaces:
    Noder

    public class SnapRoundingNoder
    extends java.lang.Object
    implements Noder
    Uses Snap Rounding to compute a rounded, fully noded arrangement from a set of SegmentStrings, in a performant way, and avoiding unnecessary noding.

    Implements the Snap Rounding technique described in the papers by Hobby, Guibas & Marimont, and Goodrich et al. Snap Rounding enforces that all output vertices lie on a uniform grid, which is determined by the provided PrecisionModel.

    Input vertices do not have to be rounded to the grid beforehand; this is done during the snap-rounding process. In fact, rounding cannot be done a priori, since rounding vertices by themselves can distort the rounded topology of the arrangement (i.e. by moving segments away from hot pixels that would otherwise intersect them, or by moving vertices across segments).

    To minimize the number of introduced nodes, the Snap-Rounding Noder avoids creating nodes at edge vertices if there is no intersection or snap at that location. However, if two different input edges contain identical segments, each of the segment vertices will be noded. This still provides fully-noded output. This is the same behaviour provided by other noders, such as MCIndexNoder and SnappingNoder.

    Version:
    1.7
    • Constructor Detail

    • Method Detail

      • getNodedSubstrings

        public java.util.Collection getNodedSubstrings()
        Description copied from interface: Noder
        Returns a Collection of fully noded SegmentStrings. The SegmentStrings have the same context as their parent.
        Specified by:
        getNodedSubstrings in interface Noder
        Returns:
        a Collection of NodedSegmentStrings representing the substrings
      • computeNodes

        public void computeNodes​(java.util.Collection inputSegmentStrings)
        Computes the nodes in the snap-rounding line arrangement. The nodes are added to the NodedSegmentStrings provided as the input.
        Specified by:
        computeNodes in interface Noder
        Parameters:
        inputSegmentStrings - a Collection of NodedSegmentStrings