這篇文章主要介紹了javascript轉換靜態圖片，增加粒子動畫效果,非常的炫酷，需要的朋友可以參考下
使用getImageData接口獲取圖片的像素點，然後基於像素點實現動畫效果，封裝成一個簡單的lib
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 <!DOCTYPE html> <html> <head> <title>particle image</title> <meta charset="utf-8" /> <style> #logo { margin-left:20px; margin-top:20px; width:160px; height:48px; background:url('./images/logo.png'); /*border: 1px solid red;*/ } </style> <script type="text/javascript" src="ParticleImage.js"></script> <script> window.onload = function() { ParticleImage.create("logo", "./images/logo.png", "fast"); }; </script> </head> <body> <div id="logo"></div> </body> </html>ParticleImage.js
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 /* The MIT License (MIT) Copyright (c) 2015 arest 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. */ /** * 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 ([email protected]) * @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);以上所述就是本文的全部內容了，希望大家能夠喜歡。