Javascript converts static images, adds particle animation effects, and javascript particles.

Source: Internet
Author: User

Javascript converts static images, adds particle animation effects, and javascript particles.

Use the getImageData interface to obtain the pixel of the image, and then implement the animation effect based on the pixel, encapsulated into a simple lib

<!DOCTYPE html>

Particle Image. js

/*The MIT License (MIT) Copyright (c) 2015 arest Permission is hereby granted, free of charge, to any person obtaining a copy ofthis software and associated documentation files (the "Software"), to deal inthe Software without restriction, including without limitation the rights touse, copy, modify, merge, publish, distribute, sublicense, and/or sell copies ofthe 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 allcopies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS ORIMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESSFOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS ORCOPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHERIN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR INCONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.*/ /** * Add particle animation for image * usage:    <script type="text/javascript" src="ParticleImage.js"></script>    <script>      window.onload = function() {        // be sure to use image file in your own server (prevent CORS issue)        ParticleImage.create("logo", "logo_s2.png", "fast");      };    </script>    // in html file    <div id="logo"></div>    // you can set default background image as usual    #logo {      margin-left:20px;      margin-top:20px;      width:160px;      height:48px;      background:url('logo_s2.png');    } * * @author tianx.qin (rushi_wowen@163.com) * @file ParticleImage.js * @version 0.9 */var ParticleImage = (function(window) {  var container = null, canvas = null;  var ctx = null, _spirit = [], timer = null,    cw = 0, ch = 0, // container width/height    iw = 0, ih = 0, // image width/height    mx = 0, my = 0, // mouse position    bMove = true,    MOVE_SPAN = 4, DEFAULT_ALPHA = 100,    speed = 100, S = {"fast":10, "mid":100, "low":300},    ALPHA = 255 * 255;   // spirit class  var Spirit = function(data) {    this.orginal = {      pos: data.pos,      x : data.x, y : data.y,      r : data.r, g : data.g, b : data.b, a : data.a    };    // change state, for animation    this.current = {      x : data.x,      y : data.y,      a : data.a    };  };   /**   * move spirit to original position   */  Spirit.prototype.move = function() {    var cur = this.current, orig = this.orginal;    if ((cur.x === orig.x) && (cur.y === orig.y)) {      //console.log("don't move:" + cur.y);      return false;    }    //console.log("move:" + cur.y);    var rand = 1 + Math.round(MOVE_SPAN * Math.random());    var offsetX = cur.x - orig.x,      offsetY = cur.y - orig.y;    var rad = offsetX == 0 ? 0 : offsetY / offsetX;    var xSpan = cur.x < orig.x ? rand : cur.x > orig.x ? -rand : 0;    cur.x += xSpan;    var tempY = xSpan == 0 ? Math.abs(rand) : Math.abs(Math.round(rad * xSpan));    var ySpan = offsetY < 0 ? tempY : offsetY > 0 ? -tempY : 0;    cur.y += ySpan;    cur.a = ((cur.x === orig.x) && (cur.y === orig.y)) ? orig.a : DEFAULT_ALPHA;    return true;  };   /**   * set random position   */  Spirit.prototype.random = function(width, height) {    var cur = this.current;    cur.x = width + Math.round(width * 2 * Math.random());    this.current.y = height + Math.round(height * 2 * Math.random());  };   /**   * set random positions for all spirits   */  var _disorder = function() {    var len = _spirit.length;    for (var i = 0; i < len; i++) {      _spirit[i].random(cw, ch);    }  };   /**   * start to move spirit   */  var _move = function() {    var sprt = _spirit;    var len = sprt.length;    var isMove = false; // whether need to move    for (var i = 0; i < len; i++) {      if (sprt[i].move()) {        isMove = true;      }    }    isMove ? _redraw() : _stopTimer();  };   /**   * redraw all spirits while animating   */  var _redraw = function() {    var imgDataObj = ctx.createImageData(iw, ih);    var imgData = imgDataObj.data;    var sprt = _spirit;    var len = sprt.length;    //console.log("redraw image : " + len);    for (var i = 0; i < len; i++) {      var temp = sprt[i];      //console.log("item : " + JSON.stringify(temp));      var orig = temp.orginal;      var cur = temp.current;      var pos = (cur.y * iw + cur.x) * 4;      imgData[pos] = orig.r;      imgData[pos + 1] = orig.g;      imgData[pos + 2] = orig.b;      imgData[pos + 3] = cur.a;    }    ctx.putImageData(imgDataObj, 0, 0);  };   /**   * add mousemove/mouseclick event   */  var _addMouseEvent = function(c) {    c.addEventListener("mouseenter", function(e) {      //console.log("e.y:" + e.clientY + ", " + container.offsetTop);      _startTimer();    });    c.addEventListener("click", function() {      // disorder all spirits and start animation      _startTimer();    });  };   /**   * calculate all pixels of the logo image   */  var _checkImage = function(imgUrl, callback) {    // var tempCanvas = document.getElementById("temp");    //canvas.width = width;    //canvas.height = height;     var proc = function(image) {      var w = image.width, h = image.height;      iw = w, ih = h;      //console.log("proc image " + image + "," + w + "," + h);      canvas = _createCanvas();      // hide container background      container.style.backgroundPosition = (-w) + "px";      container.style.backgroundRepeat = "no-repeat";      ctx.drawImage(image, 0, 0);      // this may cause security error for CORS issue      try {        var imgData = ctx.getImageData(0, 0, w, h);        var arrData = imgData.data;        for (var i = 0; i < arrData.length; i += 4) {          var r = arrData[i], g = arrData[i + 1], b = arrData[i + 2], a = arrData[i + 3];          if (r > 0 || g > 0 || b > 0 || a > 0) {            var pos = i / 4;            _spirit.push(new Spirit({              x : pos % w, y : Math.floor(pos / w),               r : r, g : g, b : b, a : a            }));          }        }        return true;      } catch (e) {        // do nothing        return false;      }      //return out;    };     var img = new Image();    img.src = imgUrl;    if (img.complete || img.complete === undefined) {      proc(img) && callback && callback();    } else {      img.onload = function() {        proc(img) && callback && callback();      };    }  };   // use "requestAnimationFrame" to create a timer, need browser support  var _timer = function(func, dur) {    //console.log("speed is " + dur);    var timeLast = null;    var bStop = false;    var bRunning = false; // prevent running more than once    var _start = function() {      if (func) {        if (! timeLast) {          timeLast = Date.now();          func();        } else {          var current = Date.now();          if (current - timeLast >= dur) {            timeLast = current;            func();          }        }      }       if (bStop) {        return;      }      requestAnimationFrame(_start);    };     var _stop = function() {      bStop = true;    };     return {      start : function() {        if (bRunning) {          //console.log("already running..");          return;        }        //console.log("start running..");        bRunning = true;        bStop = false;        _disorder();        _start();      },      stop : function() {        _stop();        bRunning = false;      }    };  };   var _startTimer = function() {    if (! timer) {      timer = _timer(function() {        bMove && _move();      }, speed);    }    timer.start();  };   var _stopTimer = function() {    timer && timer.stop();  };   /**   * start process   */  var _create = function(imgUrl) {    _checkImage(imgUrl, function() {      //_createSpirits();      _addMouseEvent(canvas);      //_startTimer();    });  };   var _setSpeed = function(s) {    S[s] && (speed = S[s]);  };   /**   * check whether browser supports canvas   */  var _support = function() {    try {      document.createElement("canvas").getContext("2d");      return true;    } catch (e) {      return false;    }  };   /**   * create a canvas element   */  var _createCanvas = function() {    var cav = document.createElement("canvas");    cav.width = iw;    cav.height = ih;    container.appendChild(cav);    ctx = cav.getContext("2d");    return cav;  };   /**   * initialize container params   */  var _init = function(c, s) {    if ((! c) || (! _support())) { // DIV id doesn't exist      return false;    }    container = c;    cw = c.clientWidth;    ch = c.clientHeight;    s && _setSpeed(s);    return true;  };   /**   * export   */  return {    "create" : function(cId, imgUrl, s) { // user can set move speed by 's'['fast','mid','low']      _init(document.getElementById(cId), s) && _create(imgUrl);    }  };})(window);

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