[转] --- 转载一份开源的高斯模糊算法
2016-05-03 23:10
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高斯模糊是非常常见的图像算法之一.
转载来源: StackBlurDemo
感谢作者.
转载来源: StackBlurDemo
感谢作者.
Canvas相关代码
<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <script type="text/javascript" src="StackBlur.js"></script> <title>Stack Blur</title> </head> <body> Original <img id="myImage" src="Model.jpg" width="320" height="568" style="border:1px solid #d3d3d3;"/> StackBlur <canvas id="myCanvas" width="320" height="568" style="border:1px solid #d3d3d3;"> Your browser does not support the HTML5 canvas tag.</canvas> <p><button onclick="myCanvas()">Try it</button></p> <script type="text/javascript"> function myCanvas() { // Firefox stackBlurImage("myImage", "myCanvas", 10, 1); return; // Chrome var img = document.getElementById("myImage"); var c = document.getElementById("myCanvas"); var context = c.getContext("2d"); preImage("Model.jpg",function(){ // context.drawImage(this, 0, 0, 320, 568); stackBlurImage("myImage", "myCanvas", 10, 1); }); } function preImage(url, callback){ var img = new Image(); //创建一个Image对象,实现图片的预下载 img.src = url; if (img.complete) { // 如果图片已经存在于浏览器缓存,直接调用回调函数 callback.call(img); return; // 直接返回,不用再处理onload事件 } img.onload = function () { //图片下载完毕时异步调用callback函数。 callback.call(img);//将回调函数的this替换为Image对象 }; } </script> </body> </html>
高斯模糊算法
StackBlur.js代码:/* StackBlur - a fast almost Gaussian Blur For Canvas Version: 0.5 Author: Mario Klingemann Contact: mario@quasimondo.com Website: http://www.quasimondo.com/StackBlurForCanvas Twitter: @quasimondo In case you find this class useful - especially in commercial projects - I am not totally unhappy for a small donation to my PayPal account mario@quasimondo.de Or support me on flattr: https://flattr.com/thing/72791/StackBlur-a-fast-almost-Gaussian-Blur-Effect-for-CanvasJavascript Copyright (c) 2010 Mario Klingemann 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. */ 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 ); // Firefox var w = img.naturalWidth; var h = img.naturalHeight; // Chrome // var w = img.width; // var h = img.height; 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 ,320, 568); 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) { // 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 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) { // 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, 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; }
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