JavaScript實現的圖像模糊演算法程式碼分享_javascript技巧-js教程-PHP中文網

專案中需要用到HTML5模糊影像，以前用GDI，GDI 中都有現成的元件來實現，HTML5中如何實現？
1.createImageData()
2.getImageData()
3.putImageData()
以上3個函數即可實現，用法和奧義，自己百度吧,我就不重複敘述了，沒多大的意義。

以下是實現模糊演算法的JS，其實還有種2B級演算法就是分佈矩陣，這樣效率提高很多倍，不過效果很差，羽化的效果不強。
實作程式碼：

複製程式碼程式碼如下:

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 );
}

函數stackBlurCanvasRGBA( id, top_x, top_y, width, height, radius )
{
    if ( isNa) radius
    var canvas = document.getElementById( id );
    var context = canvas.getContext("2d");
嘗試<    嘗試{
        imageData = context.getImageData( top_x, top_y, width, height );
     🎜>            netscape.security.PrivilegeManager.enablePrivilege( " UniversalBrowserRead");
            imageData = context.getImageData( top_x, top_y, width, height );    Alert("無法存取本地影像");
            throw new Error ("無法存取本地影像資料：" e);
            return;
        }
   ");
      throw new Error("無法存取影像資料：" e);
    }

    var Pixels = imageData.data;

  , 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_in
var div = 半徑radius 1;
    var w4 = 寬度<< 2;
    var widthMinus1 = 寬度- 1;
    var heightMinus1 = 高度- 1;
    var heightMinus1 = 高度- 1;
  > var sumFactor = radiusPlus1 * ( radiusPlus1 1 ) / 2;

    var stackStart = new BlurStack();
    var stack = stackStartStart;
for i 🎜>    {
        stack = stack.next = new BlurStack( );
        if ( i == radiusPlus1        = stackStart;
    var stackIn = null;
    var stackOut = null;

    yw = yi = 0;

    var mul_sum = mul_table[半徑]; >
    for ( y = 0; y < 高度; y )
    {
        r_in_sum = g_in_sum = b_in_sum = a_in    r_in_sum = g_in_sum = b_in_sum = a_in       r_out_sum = radiusPlus1 * ( pr = 像素[yi]);
       g_out_sum = radiusPlus1 * ( pg = 像素[yi 1] );
         a_out_sum = radiusPlus1 * ( pa = 像素[yi 3] );

        r_sum = sumFactor * pr;
               a_sum = sumFactor * pa;

        stack = stackStart;

        for( i = 0;我<半徑   stack.r = pr;
            stack.g = pg;
            stack.b = pb;
           且       }

        for( i = 1; i < radiusPlus1; i )
        {
    );
r_sum = ( stack .r = ( pr = Pixels[p])) * ( rbs = radiusPlus1 - i );
            g_sum = ( stack.g = (pg = Pixels[p 1]))) * rbs;< b stack.b = ( pb = Pixels[p 2])) * rbs;
           a_sum = ( stack.a = ( pa = Pixels[p 3])) * rbs;

>;
            g_in_sum = pg;
            b_in_sum = pb             stack = stack.next;
        }


        stackOut = stackEnd;
        for ( x = 0; x < width; x )
   = (a_sum * mul_sum) >> ; shg_sum;
            if ( pa != 0 )
           🎜>               像素[yi]   = ((r_sum * mul_sum) & gt;> shg_sum) * pa;
                像素[yi 1] = ((g_sum * mul_sum) >> shg_sum) * pa;
     pa;
            } else {
                像素[yi] = 像素[yi 1] = 像素[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 )
    {
       🎜> yi = x << 2;
        r_out_sum = radiusPlus1 * ( pr = 像素[yi]);
        c iusPlus1 * ( pb = 像素[yi 2] );
        a_out_sum = radiusPlus1 * ( pa = Pixels[yi 3]);

     🎜>        b_sum = sumFactor * pb;
a_sum = 總和* pa;

stack = stack;堆疊啟動；

for（i = 0;我 = 0;我＆lt；半徑加1； i）
{
{ stack.r = pr;
            stack.g = pg;
            stack.b = pb;
       stack.b = pb;
                 stack = stack.next;
        }

        yp = 寬度；

        for( i = 1; i <= radius; i )
        {
              r_sum = ( stack.r = ( pr = Pixels[yi])) * ( rbs = radiusPlus1 - i );
            g_sum = ( stack.g = ( pg = Pixels[yi = ( pb = Pixels[yi 2])) * rbs;
            a_sum = ( stack.a = (pa = Pixels[yi > g_in_sum = pg;
            b_in_sum = pb;
            next;

            if( i < heightMinus1 )
          = 寬度;
            }
        }

          stackOut = stackEnd ;
        for ( y = 0; < 高度；
{
            p = yi << 2;
           , ( pa > 0 )
            {
                pa = 255 / pa;
                像素[p]   = ((r_sum * mul_sum) > shg_sum ) * pa;

> sh g_sum ) * pa;
像素[p 2] = ((b_sum * mul_sum) >> shg_sum ) * pa;
           } else {
        } else {
     ;
}

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 );

}

            yi += 4;
        }
        yw += width;
    }

    for ( x = 0; x     {
            yi = x
;        r_out_sum = radiusPlus1 * ( pr = 像素[yi]);
        g_out_sum = radius_L (pm Plus1 * ( pb = 像素[ yi 2] );

        r_sum = sumFactor * pr;
        g_sum = sum       stack = stackStart;

      為（ i = 0; radiusPlus1; i )
        {
          🎜>           stack.b = pb;
            堆疊中=下一個堆疊;
        }

        yp = 寬度;

                yi = ( yp x )

            r_sum = ( stack.r = (pr = Pixels[yi])) * ( rbs = radius - i );            b_sum = ( stack.b = ( pb = Pixels[yi 2])) * rbs          g_in_sum = pg;
            b_in_sum = pb;

            stack = stack }🎜>            {
               造成

        yi = x;
        stackIn = stackStart;
     y )
        {
           p = yi             像素[p]   = (r_sum * mul_sum) >>> shg_sum;
               像素[p 2] = (b_sum * mul_sum) >> shg_sum;

            r_sum -= r_out_sum;
       b_sum -= b_out_sum;

            r_out_sum -= stackIn.r;
g_out_sum -= stackIn。 g;
            b_out_sum -= stackIn.b;

            p = ( xinus ((p = y inus)(p. 2;

            r_sum = ( r_in_sum = ( stackIn.r = Pixels[p]));
                 b_sum = ( b_in_sum = ( stackIn. b = 像素[p 2]));

            stackIn = stackIn.next;

            g_out_sum = ( pg = stackOut.g ) ;
            b_out_sum = ( pb = stackOut.b );

       sum -= pg;
            b _in_sum -= pb ;

         stackOut.next;

            yi = width;
        } );

}

函數 BlurStack()
{
    this.r = 0;
    this.g = 0;
    this.b = 0;
this this.next = null;
}