JavaScript实现的图像模糊算法代码分享


Posted in Javascript onApril 22, 2014

项目中需要用到HTML5模糊图像,以前用GDI,GDI+中都有现成的组件来实现,HTML5中如何实现?
1.createImageData()
2.getImageData()
3.putImageData()
以上3个函数即可实现,用法和奥义,自己百度吧,我就不重复叙述了,没多大的意义。

以下是实现模糊算法的JS,其实还有种2B级算法就是分布矩阵,这样效率提高很多倍,不过效果很差,羽化的效果不强。
实现代码:

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, blurAlphaChannel )
{
     var img = document.getElementById( imageID );
    var w = img.naturalWidth;
    var h = img.naturalHeight;
    var canvas = document.getElementById( canvasID );
    canvas.style.width  = w + "px";
    canvas.style.height = h + "px";
    canvas.width = w;
    canvas.height = h;
    var context = canvas.getContext("2d");
    context.clearRect( 0, 0, w, h );
    context.drawImage( img, 0, 0 );
    if ( isNaN(radius) || radius < 1 ) return;
    if ( blurAlphaChannel )
        stackBlurCanvasRGBA( canvasID, 0, 0, w, h, radius );
    else 
        stackBlurCanvasRGB( canvasID, 0, 0, w, h, 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) {
     
        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 stackBlurCanvasRGB( 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) {
  
        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,
    r_out_sum, g_out_sum, b_out_sum,
    r_in_sum, g_in_sum, b_in_sum,
    pr, pg, pb, 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 = r_sum = g_sum = b_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] );
        r_sum += sumFactor * pr;
        g_sum += sumFactor * pg;
        b_sum += sumFactor * pb;
        stack = stackStart;
        for( i = 0; i < radiusPlus1; i++ )
        {
            stack.r = pr;
            stack.g = pg;
            stack.b = pb;
            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;
            r_in_sum += pr;
            g_in_sum += pg;
            b_in_sum += pb;
            stack = stack.next;
        }
        
        stackIn = stackStart;
        stackOut = stackEnd;
        for ( x = 0; x < width; x++ )
        {
            pixels[yi]   = (r_sum * mul_sum) >> shg_sum;
            pixels[yi+1] = (g_sum * mul_sum) >> shg_sum;
            pixels[yi+2] = (b_sum * mul_sum) >> shg_sum;
            r_sum -= r_out_sum;
            g_sum -= g_out_sum;
            b_sum -= b_out_sum;
            r_out_sum -= stackIn.r;
            g_out_sum -= stackIn.g;
            b_out_sum -= stackIn.b;
            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]);
            r_sum += r_in_sum;
            g_sum += g_in_sum;
            b_sum += b_in_sum;
            stackIn = stackIn.next;
            r_out_sum += ( pr = stackOut.r );
            g_out_sum += ( pg = stackOut.g );
            b_out_sum += ( pb = stackOut.b );
            r_in_sum -= pr;
            g_in_sum -= pg;
            b_in_sum -= pb;
            stackOut = stackOut.next;
            yi += 4;
        }
        yw += width;
    }
    
    for ( x = 0; x < width; x++ )
    {
        g_in_sum = b_in_sum = r_in_sum = g_sum = b_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]);
        r_sum += sumFactor * pr;
        g_sum += sumFactor * pg;
        b_sum += sumFactor * pb;
        stack = stackStart;
        for( i = 0; i < radiusPlus1; i++ )
        {
            stack.r = pr;
            stack.g = pg;
            stack.b = pb;
            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;
            r_in_sum += pr;
            g_in_sum += pg;
            b_in_sum += pb;
            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]   = (r_sum * mul_sum) >> shg_sum;
            pixels[p+1] = (g_sum * mul_sum) >> shg_sum;
            pixels[p+2] = (b_sum * mul_sum) >> shg_sum;
            r_sum -= r_out_sum;
            g_sum -= g_out_sum;
            b_sum -= b_out_sum;
            r_out_sum -= stackIn.r;
            g_out_sum -= stackIn.g;
            b_out_sum -= stackIn.b;
            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]));
            stackIn = stackIn.next;
            r_out_sum += ( pr = stackOut.r );
            g_out_sum += ( pg = stackOut.g );
            b_out_sum += ( pb = stackOut.b );
            r_in_sum -= pr;
            g_in_sum -= pg;
            b_in_sum -= pb;
            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;
}

使用方法:

stackBlurImage( sourceImageID, targetCanvasID, radius, blurAlphaChannel );
stackBlurCanvasRGBA( targetCanvasID, top_x, top_y, width, height, radius );
stackBlurCanvasRGB( targetCanvasID, top_x, top_y, width, height, radius );
Javascript 相关文章推荐
JavaScript 无符号右移运算符
Apr 17 Javascript
Javascript控制页面链接在新窗口打开具体方法
Aug 16 Javascript
JavaScript中检测变量是否存在遇到的一些问题
Nov 11 Javascript
JavaScript中实现异步编程模式的4种方法
Sep 24 Javascript
javascript模拟实现ajax加载框实例
Oct 15 Javascript
JavaScript原生对象之Number对象的属性和方法详解
Mar 13 Javascript
JavaScript实现单击下拉框选择直接跳转页面的方法
Jul 02 Javascript
JS高仿抛物线加入购物车特效实现代码
Feb 20 Javascript
jQuery上传多张图片带进度条样式(DEMO)
Mar 02 Javascript
vue-music关于Player播放器组件详解
Nov 28 Javascript
React Native悬浮按钮组件的示例代码
Apr 05 Javascript
微信小程序实现页面跳转传递参数(实体,对象)
Aug 12 Javascript
JavaScript闭包实例讲解
Apr 22 #Javascript
JavaScript函数的4种调用方法详解
Apr 22 #Javascript
JavaScript实现存储HTML字符串示例
Apr 21 #Javascript
JavaScript获取flash对象与网上的有所不同
Apr 21 #Javascript
js unicode 编码解析关于数据转换为中文的两种方法
Apr 21 #Javascript
jquery form 加载数据示例
Apr 21 #Javascript
三种方式获取XMLHttpRequest对象
Apr 21 #Javascript
You might like
PHP set_time_limit(0)长连接的实现分析
2010/03/02 PHP
服务器变量 $_SERVER 的深入解析
2013/07/02 PHP
Thinkphp实现自动验证和自动完成
2015/12/19 PHP
php UNIX时间戳用法详解
2017/02/16 PHP
IE6图片加载的一个BUG解决方法
2010/07/13 Javascript
js中for in的用法示例解析
2013/12/25 Javascript
Jquery模仿Baidu、Google搜索时自动补充搜索结果提示
2013/12/26 Javascript
JAVA四种基本排序方法实例总结
2015/07/24 Javascript
vue router2.0二级路由的简单使用
2017/07/05 Javascript
说说AngularJS中的$parse和$eval的用法
2017/09/14 Javascript
AngularJS中下拉框的基本用法示例
2017/10/11 Javascript
javascript少儿编程关于返回值的函数内容
2018/05/27 Javascript
JS栈stack类的实现与使用方法示例
2019/01/31 Javascript
jquery.pager.js实现分页效果
2019/07/29 jQuery
js实现网页版贪吃蛇游戏
2020/02/22 Javascript
python中assert用法实例分析
2015/04/30 Python
详解Python中的元组与逻辑运算符
2015/10/13 Python
详解Python实现按任意键继续/退出的功能
2016/08/19 Python
python实现redis三种cas事务操作
2017/12/19 Python
python pandas中对Series数据进行轴向连接的实例
2018/06/08 Python
django连接mysql配置方法总结(推荐)
2018/08/18 Python
使用11行Python代码盗取了室友的U盘内容
2018/10/23 Python
python实现图片识别汽车功能
2018/11/30 Python
python3+opencv生成不规则黑白mask实例
2020/02/19 Python
windows上彻底删除jupyter notebook的实现
2020/04/13 Python
keras CNN卷积核可视化,热度图教程
2020/06/22 Python
24个canvas基础知识小结
2014/12/17 HTML / CSS
SmartBuyGlasses台湾:名牌眼镜,名牌太阳眼镜及隐形眼镜
2017/01/04 全球购物
联想台湾官网:Lenovo TW
2018/05/09 全球购物
师范大学应届生求职信
2013/11/21 职场文书
自考毕业自我鉴定
2014/03/18 职场文书
节约用水倡议书
2014/04/16 职场文书
中班下学期幼儿评语
2014/12/30 职场文书
横店影视城导游词
2015/02/06 职场文书
正则表达式拆分url实例代码
2022/02/24 Java/Android
解决Oracle数据库用户密码过期
2022/05/11 Oracle