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
• insert(vec2, index) - insert vec2 at the specified index
• remove(vecOrIndex) - remove the specified vec2 or numeric index 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
• translate(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
• union(polygon) returns a new polygon representing the boolean union of this and the incoming polygon
• cut(polygon) returns a new polygon representing the boolean cut of polygon from this
• toArray() convert this polygon into an array of arrays ([[x, y]])

license

MIT