(function(global) {
"use strict";
var requestInterval = function(fn, delay) {
var handle = {value: null};
function loop() {
handle.value = requestAnimationFrame(loop);
fn();
}
loop();
return handle;
},
cancelInterval = function(handle) {
cancelAnimationFrame(handle.value);
};
var KEYFRAME = 500,
STROKE = 0.08,
TAU = 2.0 * Math.PI,
TWO_OVER_SQRT_2 = 2.0 / Math.sqrt(2);
function circle(ctx, x, y, r) {
ctx.beginPath();
ctx.arc(x, y, r, 0, TAU, false);
ctx.stroke();
}
function puff(ctx, t, cx, cy, rx, ry, rmin, rmax) {
var c = Math.cos(t * TAU),
s = Math.sin(t * TAU);
rmax -= rmin;
circle(
ctx,
cx - s * rx,
cy + c * ry + rmax * 0.5,
rmin + (1 - c * 0.5) * rmax
);
}
function puffs(ctx, t, cx, cy, rx, ry, rmin, rmax) {
var i;
for(i = 5; i--; )
puff(ctx, t + i / 5, cx, cy, rx, ry, rmin, rmax);
}
function cloud(ctx, t, cx, cy, cw, s, color) {
t /= 30000;
var a = cw * 0.21,
b = cw * 0.12,
c = cw * 0.24,
d = cw * 0.28;
puffs(ctx, t, cx, cy, a, b, c, d);
puffs(ctx, t, cx, cy, a, b, c - s, d - s);
}
var Skycons = function(opts) {
this.list = [];
this.interval = null;
this.color = opts && opts.color ? opts.color : "black";
this.resizeClear = !!(opts && opts.resizeClear);
};
Skycons.CLOUDY = function(ctx, t, color) {
var w = ctx.canvas.width,
h = ctx.canvas.height,
s = Math.min(w, h);
cloud(ctx, t, w * 0.5, h * 0.5, s, s * STROKE, color);
};
Skycons.prototype = {
_determineDrawingFunction: function(draw) {
if(typeof draw === "string")
draw = Skycons[draw.toUpperCase().replace(/-/g, "_")] || null;
return draw;
},
add: function(el, draw) {
var obj;
if(typeof el === "string")
el = document.getElementById(el);
// Does nothing if canvas name doesn't exists
if(el === null)
return;
draw = this._determineDrawingFunction(draw);
// Does nothing if the draw function isn't actually a function
if(typeof draw !== "function")
return;
obj = {
element: el,
context: el.getContext("2d"),
drawing: draw
};
this.list.push(obj);
this.draw(obj, KEYFRAME);
},
set: function(el, draw) {
var i;
if(typeof el === "string")
el = document.getElementById(el);
for(i = this.list.length; i--; )
if(this.list[i].element === el) {
this.list[i].drawing = this._determineDrawingFunction(draw);
this.draw(this.list[i], KEYFRAME);
return;
}
this.add(el, draw);
},
remove: function(el) {
var i;
if(typeof el === "string")
el = document.getElementById(el);
for(i = this.list.length; i--; )
if(this.list[i].element === el) {
this.list.splice(i, 1);
return;
}
},
draw: function(obj, time) {
var canvas = obj.context.canvas;
if(this.resizeClear)
canvas.width = canvas.width;
else
obj.context.clearRect(0, 0, canvas.width, canvas.height);
obj.drawing(obj.context, time, this.color);
},
play: function() {
var self = this;
this.pause();
this.interval = requestInterval(function() {
var now = Date.now(),
i;
for(i = self.list.length; i--; )
self.draw(self.list[i], now);
}, 1000 / 60);
},
pause: function() {
var i;
if(this.interval) {
cancelInterval(this.interval);
this.interval = null;
}
}
};
global.Skycons = Skycons;
}(this));
var skycons = new Skycons({
"color": "black"
});
var canvas = document.querySelectorAll('canvas');
[].forEach.call(canvas, function (el) {
skycons.add(el, el.dataset.icon);
});
skycons.play();
<canvas id="fe_current_icon" data-icon="cloudy" width="160" height="160" style="width:120px; height:120px"></canvas>