effects.js

一本关于大学的书

// Copyright (c) 2005 Thomas Fuchs (http://script.aculo.us, http://mir.aculo.us)
//
// Parts (c) 2005 Justin Palmer (http://encytemedia.com/)
// Parts (c) 2005 Mark Pilgrim (http://diveintomark.org/)
// 
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.


Effect = {}
Effect2 = Effect; // deprecated

/* ------------- transitions ------------- */

Effect.Transitions = {}

Effect.Transitions.linear = function(pos) {
  return pos;
}
Effect.Transitions.sinoidal = function(pos) {
  return (-Math.cos(pos*Math.PI)/2) + 0.5;
}
Effect.Transitions.reverse  = function(pos) {
  return 1-pos;
}
Effect.Transitions.flicker = function(pos) {
  return ((-Math.cos(pos*Math.PI)/4) + 0.75) + Math.random(0.25);
}
Effect.Transitions.wobble = function(pos) {
  return (-Math.cos(pos*Math.PI*(9*pos))/2) + 0.5;
}
Effect.Transitions.pulse = function(pos) {
  return (Math.floor(pos*10) % 2 == 0 ? 
    (pos*10-Math.floor(pos*10)) : 1-(pos*10-Math.floor(pos*10)));
}
Effect.Transitions.none = function(pos) {
  return 0;
}
Effect.Transitions.full = function(pos) {
  return 1;
}

/* ------------- core effects ------------- */

Effect.Base = function() {};
Effect.Base.prototype = {
  setOptions: function(options) {
    this.options = Object.extend({
      transition: Effect.Transitions.sinoidal,
      duration:   1.0,   // seconds
      fps:        25.0,  // max. 100fps
      sync:       false, // true for combining
      from:       0.0,
      to:         1.0
    }, options || {});
  },
  start: function(options) {
    this.setOptions(options || {});
    this.currentFrame = 0;
    this.startOn      = new Date().getTime();
    this.finishOn     = this.startOn + (this.options.duration*1000);
    if(this.options.beforeStart) this.options.beforeStart(this);
    if(!this.options.sync) this.loop();  
  },
  loop: function() {
    var timePos = new Date().getTime();
    if(timePos >= this.finishOn) {
      this.render(1.0);
      if(this.finish) this.finish(); 
      if(this.options.afterFinish) this.options.afterFinish(this);
      return;  
    }
    var pos   = (timePos - this.startOn) / (this.finishOn - this.startOn);
    var frame = Math.round(pos * this.options.fps * this.options.duration);
    if(frame > this.currentFrame) {
      this.render(pos);
      this.currentFrame = frame;
    }
    this.timeout = setTimeout(this.loop.bind(this), 10);
  },
  render: function(pos) {
    if(this.options.transition) pos = this.options.transition(pos);
    pos *= (this.options.to-this.options.from);
    pos += this.options.from; 
    if(this.options.beforeUpdate) this.options.beforeUpdate(this);
    if(this.update) this.update(pos);
    if(this.options.afterUpdate) this.options.afterUpdate(this);  
  },
  cancel: function() {
    if(this.timeout) clearTimeout(this.timeout);
  }
}

Effect.Parallel = Class.create();
Object.extend(Object.extend(Effect.Parallel.prototype, Effect.Base.prototype), {
  initialize: function(effects) {
    this.effects = effects || [];
    this.start(arguments[1]);
  },
  update: function(position) {
    for (var i = 0; i < this.effects.length; i++)
      this.effects[i].render(position);  
  },
  finish: function(position) {
    for (var i = 0; i < this.effects.length; i++)
      if(this.effects[i].finish) this.effects[i].finish(position);
  }
});

// Internet Explorer caveat: works only on elements the have
// a 'layout', meaning having a given width or height. 
// There is no way to safely set this automatically.
Effect.Opacity = Class.create();
Object.extend(Object.extend(Effect.Opacity.prototype, Effect.Base.prototype), {
  initialize: function(element) {
    this.element = $(element);
    options = Object.extend({
      from: 0.0,
      to:   1.0
    }, arguments[1] || {});
    this.start(options);
  },
  update: function(position) {
    this.setOpacity(position);
  }, 
  setOpacity: function(opacity) {
    if(opacity==1.0) {
      this.element.style.opacity = null;
      this.element.style.filter  = null;
    } else {
      this.element.style.opacity = opacity;
      this.element.style.filter  = "alpha(opacity:"+opacity*100+")";
    }
  }
});

Effect.MoveBy = Class.create();
Object.extend(Object.extend(Effect.MoveBy.prototype, Effect.Base.prototype), {
  initialize: function(element, toTop, toLeft) {
    this.element      = $(element);
    this.originalTop  = parseFloat(Element.getStyle(element,'top')  || '0');
    this.originalLeft = parseFloat(Element.getStyle(element,'left') || '0');
    this.toTop        = toTop;
    this.toLeft       = toLeft;
    Element.makePositioned(this.element);
    this.start(arguments[3]);
  },
  update: function(position) {
    topd  = this.toTop  * position + this.originalTop;
    leftd = this.toLeft * position + this.originalLeft;
    this.setPosition(topd, leftd);
  },
  setPosition: function(topd, leftd) {
    this.element.style.top  = topd  + "px";
    this.element.style.left = leftd + "px";
  }
});

Effect.Scale = Class.create();
Object.extend(Object.extend(Effect.Scale.prototype, Effect.Base.prototype), {
  initialize: function(element, percent) {
    this.element = $(element)
    options = Object.extend({
      scaleX: true,
      scaleY: true,
      scaleContent: true,
      scaleFromCenter: false,
      scaleMode: 'box',        // 'box' or 'contents' or {} with provided values
      scaleFrom: 100.0
    }, arguments[2] || {});
    this.originalTop    = this.element.offsetTop;
    this.originalLeft   = this.element.offsetLeft;
    if(Element.getStyle(element,'font-size')=="") this.sizeEm = 1.0;
    if(Element.getStyle(element,'font-size') && Element.getStyle(element,'font-size').indexOf("em")>0)
      this.sizeEm      = parseFloat(Element.getStyle(element,'font-size'));
    this.factor = (percent/100.0) - (options.scaleFrom/100.0);
    if(options.scaleMode=='box') {
      this.originalHeight = this.element.clientHeight;
      this.originalWidth  = this.element.clientWidth; 
    } else 
    if(options.scaleMode=='contents') {
      this.originalHeight = this.element.scrollHeight;
      this.originalWidth  = this.element.scrollWidth;
    } else {
      this.originalHeight = options.scaleMode.originalHeight;
      this.originalWidth  = options.scaleMode.originalWidth;
    }
    this.start(options);
  },

  update: function(position) {
    currentScale = (this.options.scaleFrom/100.0) + (this.factor * position);
    if(this.options.scaleContent && this.sizeEm) 
      this.element.style.fontSize = this.sizeEm*currentScale + "em";
    this.setDimensions(
      this.originalWidth * currentScale, 
      this.originalHeight * currentScale);
  },

  setDimensions: function(width, height) {
    if(this.options.scaleX) this.element.style.width = width + 'px';
    if(this.options.scaleY) this.element.style.height = height + 'px';
    if(this.options.scaleFromCenter) {
      topd  = (height - this.originalHeight)/2;
      leftd = (width  - this.originalWidth)/2;
      if(Element.getStyle(this.element,'position')=='absolute') {
        if(this.options.scaleY) this.element.style.top = this.originalTop-topd + "px";
        if(this.options.scaleX) this.element.style.left = this.originalLeft-leftd + "px";
      } else {
        if(this.options.scaleY) this.element.style.top = -topd + "px";
        if(this.options.scaleX) this.element.style.left = -leftd + "px";
      }
    }
  }
});

Effect.Highlight = Class.create();
Object.extend(Object.extend(Effect.Highlight.prototype, Effect.Base.prototype), {
  initialize: function(element) {
    this.element = $(element);
    
    // try to parse current background color as default for endcolor
    // browser stores this as: "rgb(255, 255, 255)", convert to "#ffffff" format
    var endcolor = "#ffffff";
    var current = Element.getStyle(this.element, 'background-color');
    if(current && current.slice(0,4) == "rgb(") {
      endcolor = "#";
      var cols = current.slice(4,current.length-1).split(',');
      var i=0; do { endcolor += parseInt(cols[i]).toColorPart() } while (++i<3); }
      
    var options = Object.extend({
      startcolor:   "#ffff99",
      endcolor:     endcolor,
      restorecolor: current 
    }, arguments[1] || {});
    
    // init color calculations
    this.colors_base = [
      parseInt(options.startcolor.slice(1,3),16),
      parseInt(options.startcolor.slice(3,5),16),
      parseInt(options.startcolor.slice(5),16) ];
    this.colors_delta = [
      parseInt(options.endcolor.slice(1,3),16)-this.colors_base[0],
      parseInt(options.endcolor.slice(3,5),16)-this.colors_base[1],
      parseInt(options.endcolor.slice(5),16)-this.colors_base[2] ];

    this.start(options);
  },
  update: function(position) {
    var colors = [
      Math.round(this.colors_base[0]+(this.colors_delta[0]*position)),
      Math.round(this.colors_base[1]+(this.colors_delta[1]*position)),
      Math.round(this.colors_base[2]+(this.colors_delta[2]*position)) ];
    this.element.style.backgroundColor = "#" +
      colors[0].toColorPart() + colors[1].toColorPart() + colors[2].toColorPart();
  },
  finish: function() {
    this.element.style.backgroundColor = this.options.restorecolor;
  }
});

Effect.ScrollTo = Class.create();
Object.extend(Object.extend(Effect.ScrollTo.prototype, Effect.Base.prototype), {
  initialize: function(element) {
    this.element = $(element);
    Position.prepare();
    var offsets = Position.cumulativeOffset(this.element);
    var max = window.innerHeight ? 
      window.height - window.innerHeight :
      document.body.scrollHeight - 
        (document.documentElement.clientHeight ? 
          document.documentElement.clientHeight : document.body.clientHeight);
    this.scrollStart = Position.deltaY;
    this.delta  = (offsets[1] > max ? max : offsets[1]) - this.scrollStart;
    this.start(arguments[1] || {});
  },
  update: function(position) {
    Position.prepare();
    window.scrollTo(Position.deltaX, 
      this.scrollStart + (position*this.delta));
  }
});