filteredvector
Applies cubic smoothing to a vector valued curve. This is useful for smoothing out inputs from the mouse or other input devices.
Example
var now = require('rightnow')
var filterVector = require('filteredvector')
var smoothPosition = filterVector([256, 256])
var canvas = document.createElement('canvas')
canvas.width = 512
canvas.height = 512
document.body.appendChild(canvas)
var context = canvas.getContext('2d')
canvas.addEventListener('mousemove', function(ev) {
smoothPosition.push(now(), ev.x, ev.y)
})
function paint() {
requestAnimationFrame(paint)
var t = now()
context.fillStyle = 'rgba(0,0,0,1)'
context.fillRect(0,0,512,512)
context.strokeStyle = '#0f0'
context.lineWidth = 1
context.beginPath()
var x = smoothPosition.curve(t)
context.moveTo(x[0], x[1])
for(var i=0; i<2000; ++i) {
var y = smoothPosition.curve(Math.floor(t  i))
context.lineTo(y[0], y[1])
}
context.stroke()
}
paint()
Try out the demo in your browser.
Install
npm i filteredvector
API
Constructor
var vec = require('filteredvector')(initState[, initVelocity, initTime])
Creates a new smoothed vector with the given initial state, velocity and time.

initState
is the initial state of the vector 
initVelocity
is the initial velocity of the vector 
initTime
is the initial time of the vector
Returns A new smoothed vector valued curve
Methods
vec.curve(t)
Computes the value of the curve at time t

t
is the time parameter to sample the curve
Returns The value of the curve at time t
vec.dcurve(t)
Computes the derivative of the curve at time t

t
is the time parameter
Returns The derivative of the curve at time t
vec.bounds
A pair of arrays giving the upper and lower bounds on the constraints of the vector. Default is [Infinity,Infinity, ...]
and [Infinity,Infinity,...]
vec.push(t, ...)
Adds a new data point onto the end of the curve

t
is the time the new data point was sampled 
...
are the components of the curve vector
vec.move(t, ...)
Incrementally moves the curve from the last sampled position by an offset. This is useful with input devices that emit relative motion (for example scrolling, key press events, pointer lock)

t
is the time at which the move event occured 
...
are the components of the relative motion
vec.set(t, ...)
Sets the state of the curve at time t

t
is the time parameter to sample 
...
are the components of the state
vec.jump(t, ...)
Sets the state of the vector at time t
with no smoothing.

t
is the time parameter to sample 
...
are the components of the vector
vec.idle(t)
Adds a stationary data point to the curve (ie notify the curve that no input state has changed)

t
is the time at which the curve was idle
vec.flush(t)
Removes all samples in the buffer before time t

t
is the cutoff time
vec.lastT()
Returns The time of the last sample in the curve
vec.stable()
Returns true
is the vector is stationary as of the last event.
License
(c) 2015 Mikola Lysenko. MIT License