box-intersect-1d

Find all intersections in a collection of intervals.

Example

Full intersection

Here is how you can use this module to detect all intersections in a collection of intervals:

var boxIntersect1D = require('box-intersect-1d')
 
var boxes = [
  [0, 1],
  [0, 2],
  [10, 100],
  [5, 8],
  [1.5, 7]
]
 
boxIntersect1D.full(boxes, function(i,j) {
  console.log(i,j)
  console.log('overlap:', boxes[i], boxes[j])
})

Output

overlap: [ 0, 1 ] [ 0, 2 ]
overlap: [ 1.5, 7 ] [ 0, 2 ]
overlap: [ 5, 8 ] [ 1.5, 7 ]

Red-blue intersection

If you want to compare intersections between two different sets of intervals you can use the .bipartite version of the test:

var boxIntersect1D = require('box-intersect-1d')
 
var red = [
  [0, 1],
  [0, 2],
  [10, 100],
  [5, 8],
  [1.5, 7]
]
 
var blue = [
 [0, 100],
 [1, 2], 
 [-1, 5]
]
 
boxIntersect1D.bipartite(red, blue, function(r, b) {
  console.log('overlap:', red[r], blue[b])
})

Output

overlap: [ 0, 2 ] [ -1, 5 ]
overlap: [ 0, 2 ] [ 0, 100 ]
overlap: [ 0, 1 ] [ -1, 5 ]
overlap: [ 0, 1 ] [ 0, 100 ]
overlap: [ 0, 2 ] [ 1, 2 ]
overlap: [ 0, 1 ] [ 1, 2 ]
overlap: [ 1.5, 7 ] [ -1, 5 ]
overlap: [ 1.5, 7 ] [ 0, 100 ]
overlap: [ 1.5, 7 ] [ 1, 2 ]
overlap: [ 5, 8 ] [ -1, 5 ]
overlap: [ 5, 8 ] [ 0, 100 ]
overlap: [ 10, 100 ] [ 0, 100 ]

Install

npm install box-intersect-1d

API

var boxIntersect1D = require('box-intersect-1d')

boxIntersect1D.full(boxes, visit)

Find all pairs of boxes which intersect

• boxes is an array of intervals represented by [lo,hi] value pairs
• visit(i,j) is called for every pair over overlapping intervals with the index of the intervals. If visit returns any value other than undefined, then this terminates early with that value.

boxIntersect1D.bipartite(red, blue, visit)

Find all intersections between two sets of intervals

• red and blue are two collections of intervals as described above
• visit(r,b) is called once for every pair of intervals in red and blue which overlap. r and b are the indices of the overlapping boxes.

Credits

(c) 2014 Mikola Lysenko. MIT License