circle2

    1.1.1 • Public • Published

    circle2

    install

    npm install circle2
    

    use

    new Circle([origin [, radius])

    Where origin adheres to the following form:

    • [0, 1]
    • { x: 0, y: 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:

     
    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

     
    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

    Instance Methods

    radius([newRadius])

    Get/Set the radius of the circle

    containsPoint(point)

    Where point looks like one of the following:

    • [0, 1]
    • { x: 0, y: 1 }
    • new Vec2(0, 1)

    This function will return true if the passed point is inside or right on the boundary of the circle.

    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
    • has a function .points() or array .points - polygon
    • has .x1, .y1, .x2, and .y2 - rectangle
    • has .x, .y, .w, and .h - rectangle
    • has .x, .y, .width, and .height - rectangle

    This method will return true if the passed thing is completely inside, and false otherwise.

    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

    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 * r*2

    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

    license

    MIT (see: license.txt)

    Keywords

    Install

    npm i circle2

    DownloadsWeekly Downloads

    1,009

    Version

    1.1.1

    License

    MIT

    Last publish

    Collaborators

    • tmpvar