<!doctype html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="Generator" content="EditPlus®"> <meta name="Author" content=""> <meta name="Keywords" content=""> <meta name="Description" content=""> <title>Document</title> <style type="text/css"> *{ margin:0; padding:0; } body,html{ font-family:"Microsoft Yahei"; } #can{ display:block; margin:0 auto; } #wrap{ width:500px; height:100px; margin:0 auto; text-align:center; } </style> </head> <body> <canvas id="can" width="1000" height="500">浏览器不支持canvas</canvas> <div id="wrap"> <input type="text" id="text" value="人决定一切" width="80px"><input type="submit" id="submit"> </div> <script type="text/javascript"> window.onload = function(){ var submitDom = document.getElementById("submit"); var textDom = document.getElementById("text"); var can = document.getElementById("can"); var ctx = can.getContext("2d"); var textVal = ""; var initz = 250; var thisTIme = null; var animTime = null; var grains = []; function initAnimate(){ grains = []; textVal = textDom.value; drawText(textVal); var imgDate = ctx.getImageData(0,0,can.width,can.height); ctx.clearRect(0,0,can.width , can.height); for(var i=0;i<imgDate.width;i+=6){ for(var j=0;j<imgDate.height;j+=6){ var index = (j*imgDate.width + i)*4; if(imgDate.data[index]>128){ var grain = new Grain(i,j,0,3); grains.push(grain); } } } animate(); } var lock = true; var pause = false; /* this.x = Math.random()*can.width;//x轴坐标 this.y = Math.random()*can.height;//y轴坐标 this.z = Math.random()*initz*2;//z轴坐标 this.ix = Math.random()*can.width;//初始化x轴坐标 this.iy = Math.random()*can.height;//初始化y轴坐标 this.iz = Math.random()*initz*2;//初始化z轴坐标 this.tx = x;//目标x轴坐标 this.ty = y;//目标y轴坐标 this.tz = z;//目标z轴坐标 */ function animate(){ thisTIme = new Date(); ctx.clearRect(0,0,can.width,can.height); grains.forEach(function(item){ if(lock){ if(Math.abs(item.tx-item.x)<0.1&&Math.abs(item.ty-item.y)<0.1&&Math.abs(item.tz-item.z)<0.1){ item.x = item.tx; item.y = item.ty; item.z = item.tz; if(thisTIme-animTime>300) lock = false; } else{ item.x += (item.tx-item.x)*0.1; item.y += (item.ty-item.y)*0.1; item.z += (item.tz-item.z)*0.1; animTime = new Date(); } }else{ if(Math.abs(item.ix-item.x)<0.1&&Math.abs(item.iy-item.y)<0.1&&Math.abs(item.iz-item.z)<0.1){ item.x = item.ix; item.y = item.iy; item.z = item.iz; pause = true; console.log("执行完毕！"); } else{ item.x += (item.ix-item.x)*0.1; item.y += (item.iy-item.y)*0.1; item.z += (item.iz-item.z)*0.1; pause = false; } } item.draw(); }) if(!pause) { if("requestAnimationFrame" in window){ requestAnimationFrame(animate); } else if("webkitRequestAnimationFrame" in window){ webkitRequestAnimationFrame(animate); } else if("msRequestAnimationFrame" in window){ msRequestAnimationFrame(animate); } else if("mozRequestAnimationFrame" in window){ mozRequestAnimationFrame(animate); } } } function Grain(x,y,z,r){ this.x = Math.random()*can.width;//x轴坐标 this.y = Math.random()*can.height;//y轴坐标 this.z = Math.random()*initz*2-initz;//z轴坐标 this.ix = Math.random()*can.width;//初始化x轴坐标 this.iy = Math.random()*can.height;//初始化y轴坐标 this.iz = Math.random()*initz*2-initz;//初始化z轴坐标 this.tx = x;//目标x轴坐标 this.ty = y;//目标y轴坐标 this.tz = 0; this.r = r;//粒子半径 } Grain.prototype = { draw : function(){ ctx.save(); ctx.beginPath(); var scale = initz/(initz + this.z); ctx.fillStyle = "rgba(50,50,50,"+ scale +")"; ctx.arc(can.width/2 + (this.x-can.width/2)*scale , can.height/2 + (this.y-can.height/2) * scale, this.r*scale , 0 , 2*Math.PI); ctx.closePath(); ctx.fill(); ctx.restore(); } } function drawText(text){ ctx.save(); ctx.font = "200px 微软雅黑 bold"; ctx.fillStyle = "rgba(168,168,168,1)"; ctx.textAlign = "center" ctx.textBaseLine = "middle"; ctx.fillText(text,can.width/2,can.height/2); ctx.restore(); } submitDom.onclick = function(){ initAnimate(); lock = true; pause = false; } initAnimate(); } </script> </body> </html>
效果图：
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