npm:skiano.block

README

Skiano Block

A utility for describing positions in terms of a pattern block. You configure the size and settings of the pattern block and then ask for 'absolute' positions to be converted to positions on the pattern block.

So far only integer positions are fully tested

Installation

$ npm install skiano.block

Basic Usage

var block = require('skiano.block');
 
var width = 100,
  height = 100,
  b = block([width, height]);
  
var point = b.get(50,50); // returns [50,50]
var point = b.get(-1,-1); // returns [99,99]

Configuring Step Patterns

Steps allow for patterns that shift on the x or y axis. Sometimes reffered to as a drop.

var b = block([4,4], {
  step: 1,
  direction: 'y' // 'x' or 'y'
});

var p = b.get(6,4); // returns [2,3]

Illustration of how p works with a simple step

  0 1 2 3 4 5 6 7
0 - - - -
1 - - - - ~ ~ ~ ~
2 - - - - ~ ~ ~ ~
3 - - - - ~ ~ ~ ~
4         ~ ~ p ~  <-- point lands on a shifted block

Illustration of step options

Step 2 on the X axis    Step -2 on the Y axis (0r +1)

~ ~ ~ ~ ~ ~ ~ ~ ~ ~     ~ ~ |   |   |
|     |     |     |     |   ~ ~ ~   |
~ ~ ~ ~ ~ ~ ~ ~ ~ ~     |   |   ~ ~ ~
    |     |     |       ~ ~ ~   |   |
~ ~ ~ ~ ~ ~ ~ ~ ~ ~     |   ~ ~ ~   |
  |     |     |         |   |   ~ ~ ~
~ ~ ~ ~ ~ ~ ~ ~ ~ ~     ~ ~ ~   |   |

Getting Neighbor points

You can ask for the points surrounding a given point (and you will get the resulting points on the pattern block)

var b = block([5,5]),
  levels = 2; // default is 1

var n = b.getNeighbors([2,2], levels); // returns 'neighbors' array
// n[0] corresponds to first ring around point
// n[1] corresponds to the ring of points around n[0]

_illustration of neighbors array

  [2,2]    ->     n[0]    ->     n[1]

. . . . .      . . . . .      x x x x x
. . . . .      . x x x .      x . . . x
. . x . .  ->  . x . x .  ->  x . . . x
. . . . .      . x x x .      x . . . x
. . . . .      . . . . .      x x x x x