苹果IOS系统的毛玻璃效果非常绚丽，自己也想在HTML5中实现同样的效果
css3中可以使用blur来实现这种效果：
.blur { -webkit-filter: blur(10px);-moz-filter: blur(10px);-ms-filter: blur(10px); filter: blur(10px); }
但是使用这种方法得出来的效果不理想(比如图片模糊后四周缩小)，而且不能局部控制图片
为了解决CSS3的缺陷，我们可以使用HTML5的canvas，用过photoshop的人一定知道里面有个高斯模糊功能，其实我们要做的就是用代码实现图片的高斯模糊转换，canvas中的getImageData方法获取图片像素信息，然后写相应的算法对图片像素进行转换
对高斯模糊的转换算法感兴趣的可以参考这篇文章----点击打开链接
如果对这个算法实现不感兴趣，也可以用前人已经实现的JS类库StackBlur.js，毕竟前人栽树后人乘凉嘛。
这样高斯模糊效果不但非常理想，而且可以局部模糊图片
以下是测试代码：
index.html文件
<!doctype><html><head><link rel="stylesheet" type="text/css" href="css/index.css"/><script src="js/jquery-1.7.2.min.js" type="text/javascript"></script><script src="js/StackBlur.js" type="text/javascript"></script></head><body><img src='img/360wallpaper.jpg' id='BgImg' /><div id='main'></div><canvas id='canvas' ></canvas></body><script>//拖动function change(obj,moves) {moves.οnmοusedοwn=function(ev){var disx=0;var disy=0;var oev=ev||event;disx=oev.clientX-obj.offsetLeft;disy=oev.clientY-obj.offsetTop;document.οnmοusemοve=function(ev){var oev=ev||event;var l=oev.clientX-disx; //DIV x轴位置var t=oev.clientY-disy;//DIV y轴位置if(l<0){l=0;} else if(l>document.documentElement.clientWidth-obj.offsetWidth){l=document.documentElement.clientWidth-obj.offsetWidth;}if(t<0){t=0;}obj.style.left=l+"px";obj.style.top=t+"px";Blur();}document.οnmοuseup=function(){Blur();document.οnmοusemοve=null;document.οnmοuseup=null;}return false; //组织默认事件 }}function Blur(){stackBlurImage( 'BgImg', 'canvas', 32,'main' );}window.οnlοad=function(){var aa = document.getElementById("canvas");var bb = document.getElementById("main");change(bb,bb);}</script></html>
<pre name="code" class="html">
StackBlur.js文件
var mul_table = [512,512,456,512,328,456,335,512,405,328,271,456,388,335,292,512,454,405,364,328,298,271,496,456,420,388,360,335,312,292,273,512,482,454,428,405,383,364,345,328,312,298,284,271,259,496,475,456,437,420,404,388,374,360,347,335,323,312,302,292,282,273,265,512,497,482,468,454,441,428,417,405,394,383,373,364,354,345,337,328,320,312,305,298,291,284,278,271,265,259,507,496,485,475,465,456,446,437,428,420,412,404,396,388,381,374,367,360,354,347,341,335,329,323,318,312,307,302,297,292,287,282,278,273,269,265,261,512,505,497,489,482,475,468,461,454,447,441,435,428,422,417,411,405,399,394,389,383,378,373,368,364,359,354,350,345,341,337,332,328,324,320,316,312,309,305,301,298,294,291,287,284,281,278,274,271,268,265,262,259,257,507,501,496,491,485,480,475,470,465,460,456,451,446,442,437,433,428,424,420,416,412,408,404,400,396,392,388,385,381,377,374,370,367,363,360,357,354,350,347,344,341,338,335,332,329,326,323,320,318,315,312,310,307,304,302,299,297,294,292,289,287,285,282,280,278,275,273,271,269,267,265,263,261,259];var shg_table = [9, 11, 12, 13, 13, 14, 14, 15, 15, 15, 15, 16, 16, 16, 16, 17, 17, 17, 17, 17, 17, 17, 18, 18, 18, 18, 18, 18, 18, 18, 18, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 20, 20, 20,20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 21,21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21,21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22,22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23,23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23,23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24 ];function stackBlurImage( imageID, canvasID, radius,maindiv ){var img = document.getElementById( imageID );var canvas = document.getElementById( canvasID );var mainDiv = document.getElementById( maindiv );var oMainH = $(mainDiv).height();var oMainW = $(mainDiv).width();var oMainL = $(mainDiv).offset().left;var oMainT = $(mainDiv).offset().top;canvas.style.width = oMainW + "px";canvas.style.height = oMainH + "px";canvas.width = oMainW;canvas.height = oMainH;canvas.style.left = oMainL + "px";canvas.style.top = oMainT + "px";var context = canvas.getContext("2d");context.clearRect( 0, 0, oMainW, oMainH );context.drawImage( img,oMainL,oMainT,oMainW,oMainH, 0, 0 ,oMainW,oMainH );if ( isNaN(radius) || radius < 1 ) return;stackBlurCanvasRGBA( canvasID, 0, 0, oMainW, oMainH, radius );}function stackBlurCanvasRGBA( id, top_x, top_y, width, height, radius ){if ( isNaN(radius) || radius < 1 ) return;radius |= 0;var canvas = document.getElementById( id );var context = canvas.getContext("2d");var imageData;try {try {imageData = context.getImageData( top_x, top_y, width, height );} catch(e) {// NOTE: this part is supposedly only needed if you want to work with local files// so it might be okay to remove the whole try/catch block and just use// imageData = context.getImageData( top_x, top_y, width, height );try {netscape.security.PrivilegeManager.enablePrivilege("UniversalBrowserRead");imageData = context.getImageData( top_x, top_y, width, height );} catch(e) {alert("Cannot access local image");throw new Error("unable to access local image data: " + e);return;}}} catch(e) {alert("Cannot access image");throw new Error("unable to access image data: " + e);}var pixels = imageData.data;var x, y, i, p, yp, yi, yw, r_sum, g_sum, b_sum, a_sum, r_out_sum, g_out_sum, b_out_sum, a_out_sum,r_in_sum, g_in_sum, b_in_sum, a_in_sum, pr, pg, pb, pa, rbs;var div = radius + radius + 1;var w4 = width << 2;var widthMinus1 = width - 1;var heightMinus1 = height - 1;var radiusPlus1 = radius + 1;var sumFactor = radiusPlus1 * ( radiusPlus1 + 1 ) / 2;var stackStart = new BlurStack();var stack = stackStart;for ( i = 1; i < div; i++ ){stack = stack.next = new BlurStack();if ( i == radiusPlus1 ) var stackEnd = stack;}stack.next = stackStart;var stackIn = null;var stackOut = null;yw = yi = 0;var mul_sum = mul_table[radius];var shg_sum = shg_table[radius];for ( y = 0; y < height; y++ ){r_in_sum = g_in_sum = b_in_sum = a_in_sum = r_sum = g_sum = b_sum = a_sum = 0;r_out_sum = radiusPlus1 * ( pr = pixels[yi] );g_out_sum = radiusPlus1 * ( pg = pixels[yi+1] );b_out_sum = radiusPlus1 * ( pb = pixels[yi+2] );a_out_sum = radiusPlus1 * ( pa = pixels[yi+3] );r_sum += sumFactor * pr;g_sum += sumFactor * pg;b_sum += sumFactor * pb;a_sum += sumFactor * pa;stack = stackStart;for( i = 0; i < radiusPlus1; i++ ){stack.r = pr;stack.g = pg;stack.b = pb;stack.a = pa;stack = stack.next;}for( i = 1; i < radiusPlus1; i++ ){p = yi + (( widthMinus1 < i ? widthMinus1 : i ) << 2 );r_sum += ( stack.r = ( pr = pixels[p])) * ( rbs = radiusPlus1 - i );g_sum += ( stack.g = ( pg = pixels[p+1])) * rbs;b_sum += ( stack.b = ( pb = pixels[p+2])) * rbs;a_sum += ( stack.a = ( pa = pixels[p+3])) * rbs;r_in_sum += pr;g_in_sum += pg;b_in_sum += pb;a_in_sum += pa;stack = stack.next;}stackIn = stackStart;stackOut = stackEnd;for ( x = 0; x < width; x++ ){pixels[yi+3] = pa = (a_sum * mul_sum) >> shg_sum;if ( pa != 0 ){pa = 255 / pa;pixels[yi] = ((r_sum * mul_sum) >> shg_sum) * pa;pixels[yi+1] = ((g_sum * mul_sum) >> shg_sum) * pa;pixels[yi+2] = ((b_sum * mul_sum) >> shg_sum) * pa;} else {pixels[yi] = pixels[yi+1] = pixels[yi+2] = 0;}r_sum -= r_out_sum;g_sum -= g_out_sum;b_sum -= b_out_sum;a_sum -= a_out_sum;r_out_sum -= stackIn.r;g_out_sum -= stackIn.g;b_out_sum -= stackIn.b;a_out_sum -= stackIn.a;p = ( yw + ( ( p = x + radius + 1 ) < widthMinus1 ? p : widthMinus1 ) ) << 2;r_in_sum += ( stackIn.r = pixels[p]);g_in_sum += ( stackIn.g = pixels[p+1]);b_in_sum += ( stackIn.b = pixels[p+2]);a_in_sum += ( stackIn.a = pixels[p+3]);r_sum += r_in_sum;g_sum += g_in_sum;b_sum += b_in_sum;a_sum += a_in_sum;stackIn = stackIn.next;r_out_sum += ( pr = stackOut.r );g_out_sum += ( pg = stackOut.g );b_out_sum += ( pb = stackOut.b );a_out_sum += ( pa = stackOut.a );r_in_sum -= pr;g_in_sum -= pg;b_in_sum -= pb;a_in_sum -= pa;stackOut = stackOut.next;yi += 4;}yw += width;}for ( x = 0; x < width; x++ ){g_in_sum = b_in_sum = a_in_sum = r_in_sum = g_sum = b_sum = a_sum = r_sum = 0;yi = x << 2;r_out_sum = radiusPlus1 * ( pr = pixels[yi]);g_out_sum = radiusPlus1 * ( pg = pixels[yi+1]);b_out_sum = radiusPlus1 * ( pb = pixels[yi+2]);a_out_sum = radiusPlus1 * ( pa = pixels[yi+3]);r_sum += sumFactor * pr;g_sum += sumFactor * pg;b_sum += sumFactor * pb;a_sum += sumFactor * pa;stack = stackStart;for( i = 0; i < radiusPlus1; i++ ){stack.r = pr;stack.g = pg;stack.b = pb;stack.a = pa;stack = stack.next;}yp = width;for( i = 1; i <= radius; i++ ){yi = ( yp + x ) << 2;r_sum += ( stack.r = ( pr = pixels[yi])) * ( rbs = radiusPlus1 - i );g_sum += ( stack.g = ( pg = pixels[yi+1])) * rbs;b_sum += ( stack.b = ( pb = pixels[yi+2])) * rbs;a_sum += ( stack.a = ( pa = pixels[yi+3])) * rbs;r_in_sum += pr;g_in_sum += pg;b_in_sum += pb;a_in_sum += pa;stack = stack.next;if( i < heightMinus1 ){yp += width;}}yi = x;stackIn = stackStart;stackOut = stackEnd;for ( y = 0; y < height; y++ ){p = yi << 2;pixels[p+3] = pa = (a_sum * mul_sum) >> shg_sum;if ( pa > 0 ){pa = 255 / pa;pixels[p] = ((r_sum * mul_sum) >> shg_sum ) * pa;pixels[p+1] = ((g_sum * mul_sum) >> shg_sum ) * pa;pixels[p+2] = ((b_sum * mul_sum) >> shg_sum ) * pa;} else {pixels[p] = pixels[p+1] = pixels[p+2] = 0;}r_sum -= r_out_sum;g_sum -= g_out_sum;b_sum -= b_out_sum;a_sum -= a_out_sum;r_out_sum -= stackIn.r;g_out_sum -= stackIn.g;b_out_sum -= stackIn.b;a_out_sum -= stackIn.a;p = ( x + (( ( p = y + radiusPlus1) < heightMinus1 ? p : heightMinus1 ) * width )) << 2;r_sum += ( r_in_sum += ( stackIn.r = pixels[p]));g_sum += ( g_in_sum += ( stackIn.g = pixels[p+1]));b_sum += ( b_in_sum += ( stackIn.b = pixels[p+2]));a_sum += ( a_in_sum += ( stackIn.a = pixels[p+3]));stackIn = stackIn.next;r_out_sum += ( pr = stackOut.r );g_out_sum += ( pg = stackOut.g );b_out_sum += ( pb = stackOut.b );a_out_sum += ( pa = stackOut.a );r_in_sum -= pr;g_in_sum -= pg;b_in_sum -= pb;a_in_sum -= pa;stackOut = stackOut.next;yi += width;}}context.putImageData( imageData, top_x, top_y );}function BlurStack(){this.r = 0;this.g = 0;this.b = 0;this.a = 0;this.next = null;}
index.css文件
body{background:#000000;overflow:hidden;}#BgImg{position:absolute;z-index:-100;}#main{width:700px;height:700px;color:#ffffff;position:absolute;z-index:12;left:150px;top:30px;border-radius:1px;box-shadow:-1px -1px 4px rgba(115,115,115,0.6) inset,1px 1px 4px rgba(115,115,115,0.6) inset;}#canvas{z-index:1;position:absolute;}
这个是源码 /detail/u010852544/8611371
因为HTML5的某些函数安全需要，这个demo要放在服务器环境下使用
