# Vec2.js ![travis](https://api.travis-ci.org/tmpvar/vec2.js.png) [![browser support](https://ci.testling.com/tmpvar/vec2.js.png)](http://ci.testling.com/tmpvar/vec2.js) A generic library useful when you need to work with points/vectors in 2d space. ## Use ```javascript var a = new Vec2(10, 10), // new keyword b = Vec2(100, 10); // call the constructor directly console.log(a.distance(b)); // 90 ``` **Stuff to Note**: most of the Vec2's methods take a `returnNew` as the last parameter. If passed a truthy value, a new vector will be returned to you. Otherwise the operation will be applied to `this` and `this` will be returned. Also, since `Infinity`and `NaN` are so insidious, this library will throw as soon as it detects either of these so you can take action to fix your data/algorithm. ## Supported operations __change__([fn]) Add an observer `fn` that will be called whenever this vector changes. Calling this method without a function causes it to notify observers. `fn` signature: `function(vec, prev) {}` - where `prev` is a clone of the vector before the last operation. this function returns the passed `fn` _returns_: `Vec2`

__ignore__([fn]) Pass a `fn` to remove it from the observers list. Calling this function without a `fn` will remove all observers. _returns_: `Vec2`

__set__(x, y [, notify]) or __set__(vec2 [, notify]) Sets the `x` and `y` coordinates of this vector. If `false` is passed for `notify`, none of the observers will be called. _returns_: `Vec2`

__zero__() Sets the `x` and `y` of this vector to `0` _returns_: `Vec2`

__clone__() Returns a clone of this vector. _Note_: this does not clone observers _returns_: `Vec2`

__negate__([returnNew]) Negate the `x` and `y` coords of this vector. If `returnNew` is truthy, a new vector with the negated coordinates will be returned. _returns_: `Vec2`

__add__(x, y [, returnNew]) or __add__(array, [, returnNew]) or __add__(vec2 [, returnNew]) Add the `x` and `y` to this vector's coordinates. If `returnNew` is truthy, return a new vector containing the resulting coordinates. Otherwise apply them to this vector and return it. _returns_: `Vec2`

__subtract__(x, y [, returnNew]) or __subtract__(array, [, returnNew]) or __subtract__(vec2 [, returnNew]) _returns_: `Vec2`

__multiply__(scalar [, returnNew]) or __multiply__(x, y [, returnNew]) or __multiply__(array, [, returnNew]) or __multiply__(vec2 [, returnNew]) Multiply this vectors components with the incoming, returning a clone if `returnNew` is truthy. _returns_: `Vec2`

__divide__(scalar [, returnNew]) or __divide__(x, y [, returnNew]) or __divide__(array, [, returnNew]) or __divide__(vec2 [, returnNew]) Divide this vectors components by the incoming, returning a clone if `returnNew` is truthy. _note_: this method will throw if you attempt to divide by zero or pass values that cause NaNs _returns_: `Vec2`

__rotate__(radians [, inverse [, returnNew]]) Rotate this vector's cordinates around `(0,0)`. If `returnNew` is specified, a new `Vec2` will be created and populated with the result and returned. Otherwise the result is applied to this vector and `this` is returned. `inverse` - inverts the direction of the rotation `returnNew` - causes the result to be applied to a new `Vec2`, otherwise the result is applied to `this` _returns_: `Vec2`

__length__() Returns the length of this vector from `(0,0)` _returns_: `double`

__lengthSquared__() Returns the length of this vector prior to the `Math.sqrt` call. This is usefull when you don't need to know the actual distance, but need a normalized value to compare with another `Vec2#lengthSquared` or similar. _returns_: `double`

__distance__(vec2) _returns_: the distance between this vector and the incoming

__nearest__(array) _returns_: closest vector in array to this vector.

__normalize__([returnNew]) Normalizes this vector. If `returnNew` is truthy, a new vector populated with the normalized coordinates will be returned. _returns_: `Vec2`

__equal__(vec2) or __equal__(x, y) or __equal__(array) returns true if the incoming coordinates are the same as this vector's _returns_: `boolean` __abs__([returnNew]) Return a `Vec2` that contains the absolute value of each of this vector's parts. If `returnNew` is truthy, create a new `Vec2` and return it. Otherwise apply the absolute values to to `this`. _returns_: `Vec2`

__min__(vec) Return a `Vec2` consisting of the smallest values from this vector and the incoming When returnNew is truthy, a new `Vec2` will be returned otherwise the minimum values in either this or `vec` will be applied to this vector. _returns_: `Vec2`

__max__(vec) Return a `Vec2` consisting of the largest values from this vector and the incoming When returnNew is truthy, a new `Vec2` will be returned otherwise the maximum values in either `this` or `vec` will be applied to this vector. _returns_: `Vec2`

__clamp__(low, high [, returnNew]) Clamp the coordinates of this vector to the high/low of the incoming vec2s. If `returnNew` apply the result to the new vector and return. Otherwise apply to this vector. _returns_: `Vec2`

__lerp__(vec, amount [, returnNew]) Perform linear interpolation between this vector and the incoming. `amount` - the percentage along the path to place the vector `returnNew` - if `truthy`, apply the result to a new vector and return it, otherwise return `this` _returns_: `Vec2`

__skew__([returnNew]) Returns a vector set with the `(-y,x)` coordinates of this vector. If `returnNew` a new vector is created and the operation is applied to the new vector. _returns_: `Vec2`

__dot__() _returns_: `double`

__perpDot__() _returns_: `double`

__angleTo__(vec) returns the angle from this vector to the incoming. _returns_: `double`

__isPointOnLine__(start, end) where `start` and `end` are vec2-like (e.g. `start.x` and `start.y`) _returns_: `boolean`

__toArray__() _returns_: `[x, y]`

__fromArray__(array) Applies the `[0]` to `this.x` and `[1]` to `this.y` _returns_: `Vec2`

__toJSON__() _returns_: `{ x: ..., y: ...}`

__toString__() _returns_: `'(x, y)'` ## Install ### Browser ```html ``` ### Node install with npm npm install vec2 and then require it! var Vec2 = require('vec2'); ## License MIT (see [LICENSE.txt](LICENSE.txt))

vec2

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