polygon

utility for working with polygons (arrays of vec2s)

npm install polygon
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polygon.js

Install

nodejs

npm install polygon

Usage

Create a new polygon:

var p = new Polygon([
  Vec2(0, 0),
  Vec2(10, 0),
  Vec2(0, 10)
]);

You can pass an array of Vec2s, arrays [x, y], or objects { x: 10, y: 20 }

Supported Methods

  • each(function(prev, current, next, idx) {})
  • point(idx) - returns the point at index idx. note: this will wrap in both directions
  • dedupe(returnNew) - ensure all of the points are unique
  • remove(vec2) - remove the specified vec2 from this polygon
  • clean(returnNew) - removes contiguous points that are the same
  • winding() - returns the direction in which a polygon is wound (true === clockwise)
  • rewind(bool) - rewinds the polygon in the specified direction (true === clockwise)
  • area() - computes the area of the polygon
  • closestPointTo(vec2) - finds the closest point in this polygon to vec2
  • center() - returns a Vec2 at the center of the AABB
  • scale(amount, origin, returnNew) - scales this polygon around origin (default is this.center()) and will return a new polygon if requested with returnNew
  • containsPoint(vec2) - returns true if vec2 is inside the polygon
  • containsPolygon(poly) - returns true if poly is completely contained in this polygon
  • aabb() - returns an object {x:_, y:_, w:_, h:_} representing the axis-aligned bounding box of this polygyon
  • offset(amount) - performs an offset/buffering operation on this polygon and returns a new one
  • line(index) - return an array [startpoint, endpoint] representing the line at the specified index
  • lines(function(start, end, index) {}) - iterate over the lines in this polygon
  • selfIntersections - find self-intersections and return them as a new polygon
  • pruneSelfIntersections - remove self intersections from this polygon. returns an array of polygons
  • length - returns the number of points in this polygon
  • clone - return a new instance of this polygon
  • rotate(rads, vec2, returnNew) - rotate by origin vec2 (default this.center()) by radians rads and return a clone if returnNew is specified
  • rotate(vec2, returnNew) - translate by vec2 and return a clone if returnNew is specified
  • equal(poly) - return true if this polygon has the same components and the incoming poly
  • contains(thing) - works with an array of vec2's, an object containing a .position and .radius, an object populated with x1,y1,x2,y2, an object populated with x,y,w,h, and an object populated with x,y,width,height. See the tests for more info

license

MIT

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