spin/spin.js

//fgnass.github.com/spin.js#v1.2.5
/**
 * Copyright (c) 2011 Felix Gnass [fgnass at neteye dot de]
 * Licensed under the MIT license
 */

var prefixes = ['webkit', 'Moz', 'ms', 'O']; /* Vendor prefixes */
var animations = {}; /* Animation rules keyed by their name */
var useCssAnimations;

/**
 * Utility function to create elements. If no tag name is given,
 * a DIV is created. Optionally properties can be passed.
 */
function createEl(tag, prop) {
  var el = document.createElement(tag || 'div');
  var n;

  for(n in prop) {
    el[n] = prop[n];
  }
  return el;
}

/**
 * Appends children and returns the parent.
 */
function ins(parent /* child1, child2, ...*/) {
  for (var i=1, n=arguments.length; i<n; i++) {
    parent.appendChild(arguments[i]);
  }
  return parent;
}

/**
 * Insert a new stylesheet to hold the @keyframe or VML rules.
 */
var sheet = function() {
  var el = createEl('style');
  ins(document.getElementsByTagName('head')[0], el);
  return el.sheet || el.styleSheet;
}();

/**
 * Creates an opacity keyframe animation rule and returns its name.
 * Since most mobile Webkits have timing issues with animation-delay,
 * we create separate rules for each line/segment.
 */
function addAnimation(alpha, trail, i, lines) {
  var name = ['opacity', trail, ~~(alpha*100), i, lines].join('-');
  var start = 0.01 + i/lines*100;
  var z = Math.max(1-(1-alpha)/trail*(100-start) , alpha);
  var prefix = useCssAnimations.substring(0, useCssAnimations.indexOf('Animation')).toLowerCase();
  var pre = prefix && '-'+prefix+'-' || '';

  if (!animations[name]) {
    sheet.insertRule(
      '@' + pre + 'keyframes ' + name + '{' +
      '0%{opacity:'+z+'}' +
      start + '%{opacity:'+ alpha + '}' +
      (start+0.01) + '%{opacity:1}' +
      (start+trail)%100 + '%{opacity:'+ alpha + '}' +
      '100%{opacity:'+ z + '}' +
      '}', 0);
    animations[name] = 1;
  }
  return name;
}

/**
 * Tries various vendor prefixes and returns the first supported property.
 **/
function vendor(el, prop) {
  var s = el.style;
  var pp;
  var i;

  if(s[prop] !== undefined) return prop;
  prop = prop.charAt(0).toUpperCase() + prop.slice(1);
  for(i=0; i<prefixes.length; i++) {
    pp = prefixes[i]+prop;
    if(s[pp] !== undefined) return pp;
  }
}

/**
 * Sets multiple style properties at once.
 */
function css(el, prop) {
  for (var n in prop) {
    el.style[vendor(el, n)||n] = prop[n];
  }
  return el;
}

/**
 * Fills in default values.
 */
function merge(obj) {
  for (var i=1; i < arguments.length; i++) {
    var def = arguments[i];
    for (var n in def) {
      if (obj[n] === undefined) obj[n] = def[n];
    }
  }
  return obj;
}

/**
 * Returns the absolute page-offset of the given element.
 */
function pos(el) {
  var o = {x:el.offsetLeft, y:el.offsetTop};
  while((el = el.offsetParent)) {
    o.x+=el.offsetLeft;
    o.y+=el.offsetTop;
  }
  return o;
}

var defaults = {
  lines: 12,            // The number of lines to draw
  length: 7,            // The length of each line
  width: 5,             // The line thickness
  radius: 10,           // The radius of the inner circle
  rotate: 0,            // rotation offset
  color: '#000',        // #rgb or #rrggbb
  speed: 1,             // Rounds per second
  trail: 100,           // Afterglow percentage
  opacity: 1/4,         // Opacity of the lines
  fps: 20,              // Frames per second when using setTimeout()
  zIndex: 2e9,          // Use a high z-index by default
  className: 'spinner', // CSS class to assign to the element
  top: 'auto',          // center vertically
  left: 'auto'          // center horizontally
};

/** The constructor */
var Spinner = function Spinner(o) {
  if (!this.spin) return new Spinner(o);
  this.opts = merge(o || {}, Spinner.defaults, defaults);
};

Spinner.defaults = {};
merge(Spinner.prototype, {
  spin: function(target) {
    this.stop();
    var self = this;
    var o = self.opts;
    var el = self.el = css(createEl(0, {className: o.className}), {position: 'relative', zIndex: o.zIndex});
    var mid = o.radius+o.length+o.width;
    var ep; // element position
    var tp; // target position

    if (target) {
      target.insertBefore(el, target.firstChild||null);
      tp = pos(target);
      ep = pos(el);
      css(el, {
        left: (o.left == 'auto' ? tp.x-ep.x + (target.offsetWidth >> 1) : o.left+mid) + 'px',
        top: (o.top == 'auto' ? tp.y-ep.y + (target.offsetHeight >> 1) : o.top+mid)  + 'px'
      });
    }

    el.setAttribute('aria-role', 'progressbar');
    self.lines(el, self.opts);

    if (!useCssAnimations) {
      // No CSS animation support, use setTimeout() instead
      var i = 0;
      var fps = o.fps;
      var f = fps/o.speed;
      var ostep = (1-o.opacity)/(f*o.trail / 100);
      var astep = f/o.lines;

      !function anim() {
        i++;
        for (var s=o.lines; s; s--) {
          var alpha = Math.max(1-(i+s*astep)%f * ostep, o.opacity);
          self.opacity(el, o.lines-s, alpha, o);
        }
        self.timeout = self.el && setTimeout(anim, ~~(1000/fps));
      }();
    }
    return self;
  },
  stop: function() {
    var el = this.el;
    if (el) {
      clearTimeout(this.timeout);
      if (el.parentNode) el.parentNode.removeChild(el);
      this.el = undefined;
    }
    return this;
  },
  lines: function(el, o) {
    var i = 0;
    var seg;

    function fill(color, shadow) {
      return css(createEl(), {
        position: 'absolute',
        width: (o.length+o.width) + 'px',
        height: o.width + 'px',
        background: color,
        boxShadow: shadow,
        transformOrigin: 'left',
        transform: 'rotate(' + ~~(360/o.lines*i+o.rotate) + 'deg) translate(' + o.radius+'px' +',0)',
        borderRadius: (o.width>>1) + 'px'
      });
    }
    for (; i < o.lines; i++) {
      seg = css(createEl(), {
        position: 'absolute',
        top: 1+~(o.width/2) + 'px',
        transform: o.hwaccel ? 'translate3d(0,0,0)' : '',
        opacity: o.opacity,
        animation: useCssAnimations && addAnimation(o.opacity, o.trail, i, o.lines) + ' ' + 1/o.speed + 's linear infinite'
      });
      if (o.shadow) ins(seg, css(fill('#000', '0 0 4px ' + '#000'), {top: 2+'px'}));
      ins(el, ins(seg, fill(o.color, '0 0 1px rgba(0,0,0,.1)')));
    }
    return el;
  },
  opacity: function(el, i, val) {
    if (i < el.childNodes.length) el.childNodes[i].style.opacity = val;
  }
});

/////////////////////////////////////////////////////////////////////////
// VML rendering for IE
/////////////////////////////////////////////////////////////////////////

/**
 * Check and init VML support
 */
!function() {

  function vml(tag, attr) {
    return createEl('<' + tag + ' xmlns="urn:schemas-microsoft.com:vml" class="spin-vml">', attr);
  }

  var s = css(createEl('group'), {behavior: 'url(#default#VML)'});

  if (!vendor(s, 'transform') && s.adj) {

    // VML support detected. Insert CSS rule ...
    sheet.addRule('.spin-vml', 'behavior:url(#default#VML)');

    Spinner.prototype.lines = function(el, o) {
      var r = o.length+o.width;
      var s = 2*r;

      function grp() {
        return css(vml('group', {coordsize: s +' '+s, coordorigin: -r +' '+-r}), {width: s, height: s});
      }

      var margin = -(o.width+o.length)*2+'px';
      var g = css(grp(), {position: 'absolute', top: margin, left: margin});

      var i;

      function seg(i, dx, filter) {
        ins(g,
          ins(css(grp(), {rotation: 360 / o.lines * i + 'deg', left: ~~dx}),
            ins(css(vml('roundrect', {arcsize: 1}), {
                width: r,
                height: o.width,
                left: o.radius,
                top: -o.width>>1,
                filter: filter
              }),
              vml('fill', {color: o.color, opacity: o.opacity}),
              vml('stroke', {opacity: 0}) // transparent stroke to fix color bleeding upon opacity change
            )
          )
        );
      }

      if (o.shadow) {
        for (i = 1; i <= o.lines; i++) {
          seg(i, -2, 'progid:DXImageTransform.Microsoft.Blur(pixelradius=2,makeshadow=1,shadowopacity=.3)');
        }
      }
      for (i = 1; i <= o.lines; i++) seg(i);
      return ins(el, g);
    };
    Spinner.prototype.opacity = function(el, i, val, o) {
      var c = el.firstChild;
      o = o.shadow && o.lines || 0;
      if (c && i+o < c.childNodes.length) {
        c = c.childNodes[i+o]; c = c && c.firstChild; c = c && c.firstChild;
        if (c) c.opacity = val;
      }
    };
  }
  else {
    useCssAnimations = vendor(s, 'animation');
  }
}();

module.exports = Spinner;