js特效怎么使用方法 js实现特效 _js特效怎么使用方法

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前端
小试牛刀，实现了六款简单常见HTML5 Canvas特效滤镜，并且封装成一个纯JavaScript可调用的API文件gloomyfishfilter.js 。支持的特效滤镜分别为：
1.反色
2.灰色调
3.模糊
4.浮雕
5.雕刻
6.合理
滤镜原理解释：
2.灰色调：获取一个预期点RGB值r，g，b则新的RGB值
newr =（r * 0.272）+（g * 0.534）+（b * 0.131）;
newg =（r * 0.349）+（g * 0.686）+（b * 0.168）;
newb =（r * 0.393）+（g * 0.769）+（b * 0.189）;
3.模糊：基于一个5 * 5的卷积核
4.浮雕与雕刻：
根据当前预期的前一个预期RGB值与它的后一个重新的RGB值之差再加上128
5.总体：模拟了物体在镜子中与之对应的效果。
杂项准备1、如何获取Canvas 2d context对象

var canvas = document.getElementById("target");canvas.width = source.clientWidth;canvas.height = source.clientHeight;**if**(!canvas.getContext) {console.log("Canvas not supported. Please install a HTML5compatible browser.");**return**;}// get 2D context of canvas and draw imagetempContext = canvas.getContext("2d");

2、如何添加一个DOM img对象到Canvas对象中
var source = document.getElementById("source");tempContext.drawImage(source, 0, 0, canvas.width,canvas.height);3、如何从Canvas对象中获取预定数据

var canvas = document.getElementById("target");var len = canvas.width * canvas.height * 4;var canvasData = http://www.mnbkw.com/jxjc/179596/tempContext.getImageData(0, 0, canvas.width, canvas.height);var binaryData = canvasData.data;

4、如何对DOM对象实现鼠标ClickEvent绑定

function bindButtonEvent(element, type, handler) {if(element.addEventListener){element.addEventListener(type, handler,**false**);}else{element.attachEvent('on'+type, handler);// for IE6,7,8} }

5、如何调用实现的gfilter API完成滤镜功能

<scriptsrc=http://www.mnbkw.com/jxjc/179596/*"gloomyfishfilter.js"*></script> //导入API文件gfilter.colorInvertProcess(binaryData, len); //调用 API

6、浏览器支持：IE，FF，Chrome上测试通过，其中IE上支持通过以下标签实现：
<meta http-equiv="X-UA-Compatible"*content=*"chrome=IE8"> 效果演示：

应用程序源代码：
CSS部分：

#svgContainer {width:800px;height:600px;background-color:#EEEEEE;}#sourceDiv { float: left; border: 2px solid blue} #targetDiv { float: right;border: 2px solid red}

filter1.html中HTML源代码：

<!DOCTYPE html><html><head><meta http-equiv="X-UA-Compatible" content="chrome=IE8"><meta http-equiv="Content-type" content="text/html;charset=UTF-8"><title>Canvas Filter Demo</title><link href="http://www.mnbkw.com/jxjc/179596/default.css" rel="stylesheet" /><script src="http://www.mnbkw.com/jxjc/179596/gloomyfishfilter.js"></scrip></head><body><h1>HTML Canvas Image Process - By Gloomy Fish</h1><div id="svgContainer"><div id="sourceDiv"><img id="source" src="http://www.mnbkw.com/jxjc/test.png" /></div><div id="targetDiv"><canvas id="target"></canvas></div></div><div id="btn-group"><button type="button" id="invert-button">反色</button><button type="button" id="adjust-button">灰色调</button><button type="button" id="blur-button">模糊</button><button type="button" id="relief-button">浮雕</button><button type="button" id="diaoke-button">雕刻</button><button type="button" id="mirror-button">镜像</button></div></body></html>

filter1.html中JavaScript源代码：

var tempContext = null; // global variable 2d contextwindow.onload = function() {var source = document.getElementById("source");var canvas = document.getElementById("target");canvas.width = source.clientWidth;canvas.height = source.clientHeight;if (!canvas.getContext) {console.log("Canvas not supported. Please install a HTML5 compatible browser.");return;}// get 2D context of canvas and draw imagetempContext = canvas.getContext("2d");tempContext.drawImage(source, 0, 0, canvas.width, canvas.height);// initialization actionsvar inButton = document.getElementById("invert-button");var adButton = document.getElementById("adjust-button");var blurButton = document.getElementById("blur-button");var reButton = document.getElementById("relief-button");var dkButton = document.getElementById("diaoke-button");var mirrorButton = document.getElementById("mirror-button");// bind mouse click eventbindButtonEvent(inButton, "click", invertColor);bindButtonEvent(adButton, "click", adjustColor);bindButtonEvent(blurButton, "click", blurImage);bindButtonEvent(reButton, "click", fudiaoImage);bindButtonEvent(dkButton, "click", kediaoImage);bindButtonEvent(mirrorButton, "click", mirrorImage);}function bindButtonEvent(element, type, handler){if(element.addEventListener) {element.addEventListener(type, handler, false);} else {element.attachEvent('on'+type, handler); // for IE6,7,8}}function invertColor() {var canvas = document.getElementById("target");var len = canvas.width * canvas.height * 4;var canvasData = http://www.mnbkw.com/jxjc/179596/tempContext.getImageData(0, 0, canvas.width, canvas.height);var binaryData = canvasData.data;// Processing all the pixelsgfilter.colorInvertProcess(binaryData, len);// Copying back canvas data to canvastempContext.putImageData(canvasData, 0, 0);}function adjustColor() {var canvas = document.getElementById("target");var len = canvas.width * canvas.height * 4;var canvasData = http://www.mnbkw.com/jxjc/179596/tempContext.getImageData(0, 0, canvas.width, canvas.height);var binaryData = canvasData.data;// Processing all the pixelsgfilter.colorAdjustProcess(binaryData, len);// Copying back canvas data to canvastempContext.putImageData(canvasData, 0, 0);}function blurImage() {var canvas = document.getElementById("target");var len = canvas.width * canvas.height * 4;var canvasData = http://www.mnbkw.com/jxjc/179596/tempContext.getImageData(0, 0, canvas.width, canvas.height);// Processing all the pixelsgfilter.blurProcess(tempContext, canvasData);// Copying back canvas data to canvastempContext.putImageData(canvasData, 0, 0);}function fudiaoImage() {var canvas = document.getElementById("target");var len = canvas.width * canvas.height * 4;var canvasData = http://www.mnbkw.com/jxjc/179596/tempContext.getImageData(0, 0, canvas.width, canvas.height);// Processing all the pixelsgfilter.reliefProcess(tempContext, canvasData);// Copying back canvas data to canvastempContext.putImageData(canvasData, 0, 0);}function kediaoImage() {var canvas = document.getElementById("target");var len = canvas.width * canvas.height * 4;var canvasData = http://www.mnbkw.com/jxjc/179596/tempContext.getImageData(0, 0, canvas.width, canvas.height);// Processing all the pixelsgfilter.diaokeProcess(tempContext, canvasData);// Copying back canvas data to canvastempContext.putImageData(canvasData, 0, 0);}function mirrorImage() {var canvas = document.getElementById("target");var len = canvas.width * canvas.height * 4;var canvasData = http://www.mnbkw.com/jxjc/179596/tempContext.getImageData(0, 0, canvas.width, canvas.height);// Processing all the pixelsgfilter.mirrorProcess(tempContext, canvasData);// Copying back canvas data to canvastempContext.putImageData(canvasData, 0, 0);}

滤镜源代码（gloomyfishfilter.js）：
【js特效怎么使用方法 js实现特效】

var gfilter = {type: "canvas",name: "filters",author: "zhigang",getInfo: function () {return this.author + ' ' + this.type + ' ' + this.name;},/*** invert color value of pixel, new pixel = RGB(255-r, 255-g, 255 - b)** @param binaryData - canvas's imagedata.data* @param l - length of data (width * height of image data)*/colorInvertProcess: function(binaryData, l) {for (var i = 0; i < l; i += 4) {var r = binaryData[i];var g = binaryData[i + 1];var b = binaryData[i + 2];binaryData[i] = 255-r;binaryData[i + 1] = 255-g;binaryData[i + 2] = 255-b;}},/*** adjust color values and make it more darker and gray...** @param binaryData* @param l*/colorAdjustProcess: function(binaryData, l) {for (var i = 0; i < l; i += 4) {var r = binaryData[i];var g = binaryData[i + 1];var b = binaryData[i + 2];binaryData[i] = (r * 0.272) + (g * 0.534) + (b * 0.131);binaryData[i + 1] = (r * 0.349) + (g * 0.686) + (b * 0.168);binaryData[i + 2] = (r * 0.393) + (g * 0.769) + (b * 0.189);}},/*** deep clone image data of canvas** @param context* @param src* @returns*/copyImageData: function(context, src){var dst = context.createImageData(src.width, src.height);dst.data.set(src.data);return dst;},/*** convolution - keneral size 5*5 - blur effect filter(模糊效果)** @param context* @param canvasData*/blurProcess: function(context, canvasData) {console.log("Canvas Filter - blur process");var tempCanvasData = http://www.mnbkw.com/jxjc/179596/this.copyImageData(context, canvasData);var sumred = 0.0, sumgreen = 0.0, sumblue = 0.0;for ( var x = 0; x < tempCanvasData.width; x++) {for ( var y = 0; y < tempCanvasData.height; y++) {// Index of the pixel in the arrayvar idx = (x + y * tempCanvasData.width) * 4;for(var subCol=-2; subCol<=2; subCol++) {var colOff = subCol + x;if(colOff <0 || colOff >= tempCanvasData.width) {colOff = 0;}for(var subRow=-2; subRow<=2; subRow++) {var rowOff = subRow + y;if(rowOff < 0 || rowOff >= tempCanvasData.height) {rowOff = 0;}var idx2 = (colOff + rowOff * tempCanvasData.width) * 4;var r = tempCanvasData.data[idx2 + 0];var g = tempCanvasData.data[idx2 + 1];var b = tempCanvasData.data[idx2 + 2];sumred += r;sumgreen += g;sumblue += b;}}// calculate new RGB valuevar nr = (sumred / 25.0);var ng = (sumgreen / 25.0);var nb = (sumblue / 25.0);// clear previous for next pixel pointsumred = 0.0;sumgreen = 0.0;sumblue = 0.0;// assign new pixel valuecanvasData.data[idx + 0] = nr; // Red channelcanvasData.data[idx + 1] = ng; // Green channelcanvasData.data[idx + 2] = nb; // Blue channelcanvasData.data[idx + 3] = 255; // Alpha channel}}},/*** after pixel value - before pixel value + 128* 浮雕效果*/reliefProcess: function(context, canvasData) {console.log("Canvas Filter - relief process");var tempCanvasData = http://www.mnbkw.com/jxjc/179596/this.copyImageData(context, canvasData);for ( var x = 1; x < tempCanvasData.width-1; x++){for ( var y = 1; y < tempCanvasData.height-1; y++){// Index of the pixel in the arrayvar idx = (x + y * tempCanvasData.width) * 4;var bidx = ((x-1) + y * tempCanvasData.width) * 4;var aidx = ((x+1) + y * tempCanvasData.width) * 4;// calculate new RGB valuevar nr = tempCanvasData.data[aidx + 0] - tempCanvasData.data[bidx + 0] + 128;var ng = tempCanvasData.data[aidx + 1] - tempCanvasData.data[bidx + 1] + 128;var nb = tempCanvasData.data[aidx + 2] - tempCanvasData.data[bidx + 2] + 128;nr = (nr < 0) ? 0 : ((nr >255) ? 255 : nr);ng = (ng < 0) ? 0 : ((ng >255) ? 255 : ng);nb = (nb < 0) ? 0 : ((nb >255) ? 255 : nb);// assign new pixel valuecanvasData.data[idx + 0] = nr; // Red channelcanvasData.data[idx + 1] = ng; // Green channelcanvasData.data[idx + 2] = nb; // Blue channelcanvasData.data[idx + 3] = 255; // Alpha channel}}},/***before pixel value - after pixel value + 128*雕刻效果** @param canvasData*/diaokeProcess: function(context, canvasData) {console.log("Canvas Filter - process");var tempCanvasData = http://www.mnbkw.com/jxjc/179596/this.copyImageData(context, canvasData);for ( var x = 1; x < tempCanvasData.width-1; x++){for ( var y = 1; y < tempCanvasData.height-1; y++){// Index of the pixel in the arrayvar idx = (x + y * tempCanvasData.width) * 4;var bidx = ((x-1) + y * tempCanvasData.width) * 4;var aidx = ((x+1) + y * tempCanvasData.width) * 4;// calculate new RGB valuevar nr = tempCanvasData.data[bidx + 0] - tempCanvasData.data[aidx + 0] + 128;var ng = tempCanvasData.data[bidx + 1] - tempCanvasData.data[aidx + 1] + 128;var nb = tempCanvasData.data[bidx + 2] - tempCanvasData.data[aidx + 2] + 128;nr = (nr < 0) ? 0 : ((nr >255) ? 255 : nr);ng = (ng < 0) ? 0 : ((ng >255) ? 255 : ng);nb = (nb < 0) ? 0 : ((nb >255) ? 255 : nb);// assign new pixel valuecanvasData.data[idx + 0] = nr; // Red channelcanvasData.data[idx + 1] = ng; // Green channelcanvasData.data[idx + 2] = nb; // Blue channelcanvasData.data[idx + 3] = 255; // Alpha channel}}},/*** mirror reflect** @param context* @param canvasData*/mirrorProcess : function(context, canvasData) {console.log("Canvas Filter - process");var tempCanvasData = http://www.mnbkw.com/jxjc/179596/this.copyImageData(context, canvasData);for ( var x = 0; x < tempCanvasData.width; x++) // column{for ( var y = 0; y < tempCanvasData.height; y++) // row{// Index of the pixel in the arrayvar idx = (x + y * tempCanvasData.width) * 4;var midx = (((tempCanvasData.width -1) - x) + y * tempCanvasData.width) * 4;// assign new pixel valuecanvasData.data[midx + 0] = tempCanvasData.data[idx + 0]; // Red channelcanvasData.data[midx + 1] = tempCanvasData.data[idx + 1]; ; // Green channelcanvasData.data[midx + 2] = tempCanvasData.data[idx + 2]; ; // Blue channelcanvasData.data[midx + 3] = 255; // Alpha channel}}},};