npm install circle2``
npm install circle2
new __Circle__([origin [, radius])
Where origin adheres to the following form:
* [0, 1]
*
and radius is a number
_Note:_ the arguments to the Circle function are optional. If none are passed circle.position will be 0, 0 and circle.radius will be 1
You can also pass in a 3 points and have the circle computed from them:
`javascript
var circle = Circle([
[0, 0],
[10, 0],
[0, 10]
])
console.log(circle.radius()); // 10
console.log(circle.position); // { x: 0, y: 0 }
`
or an 3-item array of Vec2
`javascript
var circle = Circle([
Vec2(0, 0),
Vec2(10, 0),
Vec2(0, 10)
])
console.log(circle.radius()); // 10
console.log(circle.position); // { x: 0, y: 0 }
`
_Note:_ changing the passed Vec2s will change the circle
__radius__([newRadius])
Get/Set the radius of the circle
__containsPoint__(point)
Where point looks like one of the following:
* [0, 1]
*
*
This function will return true if the passed point is inside or right on the boundary of the circle.
`javascript
var Circle = require('circle2');
var c = Circle()
console.log(c.contains([10, 0])) // false
c.radius(10);
console.log(c.contains([10, 0])); // true
`
__contains__(thing)
Where thing meets the following criteria:
* has .position and .radius() - _circle_.points()
* has a function or array .points - _polygon_.x1
* has , .y1, .x2, and .y2 - _rectangle_.x
* has , .y, .w, and .h - _rectangle_.x
* has , .y, .width, and .height - _rectangle_
This method will return true if the passed thing is completely inside, and false otherwise.
`javascript
var Circle = require('circle2');
var center = [0, 0];
var c = new Circle(center, 10)
var c2 = new Circle(center, 5)
console.log(c.contains(c2)); // true
`
_Note_: if the points of thing are on the circumference of the circle, this method will return true
__change__(fn)
This is a method that you want to have called any time the circle changes. Either in radius or position
`javascript
var c = new Circle();
var trackCircleRadius = c.change(function(circle) {
// do stuff. c === circle
});
c.radius(10); // this will call trackCircleRadius
__ignore__([fn])
Takes an optional fn parameter which if passed will remove the specified listener.
If no fn is passed, _all_ the listeners will be removed.
__notify__()
Force listeners to be called.
__area__()
Returns the area PI * r^2
__circumference__()
Returns the circumference PI r2
__intersectCircle__(circle)
Performs an intersection between this circle and the incoming. Results are as follows:
* false - no intersection or one circle is contained in the other[]
* - same circles[Vec2]
* - single intersection[Vec2, Vec2]` - two intersection points
*
__toSegments__([segments])
Convert this circle into a series of points representing the outline of this circle
MIT (see: license.txt)