canvas滤镜6种效果吗详解编程语言

昨天写了一个canvas滤镜的取反色效果，今天加一点效果，主要思路都是一样的，改变getImageData.data[]的值，并返回

代码如下：

!DOCTYPE html

html

head

meta charset= UTF-8

title Canvas Filter Demo /title

style type= text/css

#wrap {

width: 600px;

height: 600px;

background-color: #EEEEEE;

}

#sourceDiv {

float: left;

border: 2px solid blue;

}

#canvasDiv {

float: right;

border: 2px solid red;

}

/style

/head

body

! 最大的wrap

div id= wrap

div id= sourceDiv ! 图片

img id= img src= img/bg6.jpg /

/div

! 画布

div id= canvasDiv

canvas id= canvas /canvas

/div

/div

! 按钮组

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

script type= text/javascript

window.onload = function() {

var img = document.getElementById( img );

var canvas = document.getElementById( canvas );

canvas.width = img.clientWidth;

canvas.height = img.clientHeight;

// get 2D context of canvas and draw image  

pen = canvas.getContext( 2d );

pen.drawImage(img, 0, 0, canvas.width, canvas.height);//把图片放在画布上

//获取到所有的按钮  

var 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 );

// 给按钮添加事件 

bindButtonEvent(inButton, click , invertColor);

bindButtonEvent(adButton, click , adjustColor);

bindButtonEvent(blurButton, click , blurImage);

bindButtonEvent(reButton, click , fudiaoImage);

bindButtonEvent(dkButton, click , kediaoImage);

bindButtonEvent(mirrorButton, click , mirrorImage);

}

//考虑到浏览器兼容

function bindButtonEvent(element, type, handler) {

if(element.addEventListener) {

element.addEventListener(type, handler, false);

} else {

element.attachEvent( on + type, handler); // for IE6,7,8  

}

}

//通用代码  得到画布上的图片像素数据 返回ImageData对象

function getUseData(canvas){ //形参为画布

//getImageData() 复制画布上指定矩形的像素数据 然后通过putImageData()将图像数据放回画布：

//返回ImageData对象，该对象拷贝了画布指定矩形的像素数据

//对于 ImageData 对象中的每个像素，都存在着四方面的信息,即 RGBA 值 eg:red=ImageData.data[0];

return pen.getImageData(0, 0, canvas.width, canvas.height);

}

function getUseLen(canvas){ //形参为画布 

return canvas.width * canvas.height * 4;//图片的数据长度的像素值 图片是由像素组成的

}

//反色

function invertColor() {

var len = getUseLen(canvas);

var canvasData =getUseData(canvas);

//color/alpha 信息以数组形式存在，并存储于 ImageData 对象的 data 属性中

var binaryData = canvasData.data;//存图片的像素值

// 处理所有的像素  

gfilter.colorInvertProcess(binaryData, len);

// 将图像数据放回画布  

pen.putImageData(canvasData, 0, 0);

}

//灰色调

function adjustColor() {

var canvasData = getUseData(canvas);

var len=getUseLen(canvas);

var binaryData = canvasData.data;

gfilter.colorAdjustProcess(binaryData, len);

pen.putImageData(canvasData, 0, 0);

}

//模糊

function blurImage() {

var canvasData = getUseData(canvas);

var len=getUseLen(canvas);

gfilter.blurProcess(pen, canvasData);

pen.putImageData(canvasData, 0, 0);

}

//浮雕

function fudiaoImage() {

var canvasData = getUseData(canvas);

var len=getUseLen(canvas);

gfilter.reliefProcess(pen, canvasData);

pen.putImageData(canvasData, 0, 0);

}

//雕刻

function kediaoImage() {

var canvasData = getUseData(canvas);

var len=getUseLen(canvas);

gfilter.diaokeProcess(pen, canvasData);

pen.putImageData(canvasData, 0, 0);

}

//镜像

function mirrorImage() {

var canvasData = getUseData(canvas);

var len=getUseLen(canvas);

gfilter.mirrorProcess(pen, canvasData);

pen.putImageData(canvasData, 0, 0);

}

 

var gfilter = {

type: canvas ,

name: filters ,

author: zhigang ,

getInfo: function() {

return this.author + + this.type + + this.name;

},

 

//取反色new pixel = RGB(255-r, 255-g, 255 b)

colorInvertProcess: function(binaryData, l) {

for(var i = 0; i 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;

}

},

/*灰色调*/

colorAdjustProcess: function(binaryData, l) {

for(var i = 0; i 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);

}

},

 

 

copyImageData: function(context, src) {

var dst = context.createImageData(src.width, src.height);

dst.data.set(src.data);

return dst;

},

 

/*图像模糊*/

blurProcess: function(context, canvasData) {

console.log( Canvas Filter blur process );

var tempCanvasData = 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 array      

var 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 value  

var nr = (sumred / 25.0);

var ng = (sumgreen / 25.0);

var nb = (sumblue / 25.0);

 

// clear previous for next pixel point  

sumred = 0.0;

sumgreen = 0.0;

sumblue = 0.0;

 

// assign new pixel value      

canvasData.data[idx + 0] = nr; // Red channel      

canvasData.data[idx + 1] = ng; // Green channel      

canvasData.data[idx + 2] = nb; // Blue channel      

canvasData.data[idx + 3] = 255; // Alpha channel      

}

}

},

 

/**  * 浮雕效果 after pixel value before pixel value + 128  */

reliefProcess: function(context, canvasData) {

console.log( Canvas Filter relief process );

var tempCanvasData = 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 array      

var 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 value  

var 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 value      

canvasData.data[idx + 0] = nr; // Red channel      

canvasData.data[idx + 1] = ng; // Green channel      

canvasData.data[idx + 2] = nb; // Blue channel      

canvasData.data[idx + 3] = 255; // Alpha channel      

}

}

},

 

/**  雕刻效果  before pixel value after pixel value + 128 */

diaokeProcess: function(context, canvasData) {

console.log( Canvas Filter process );

var tempCanvasData = 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 array      

var 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 value  

var 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 value      

canvasData.data[idx + 0] = nr; // Red channel      

canvasData.data[idx + 1] = ng; // Green channel      

canvasData.data[idx + 2] = nb; // Blue channel      

canvasData.data[idx + 3] = 255; // Alpha channel      

}

}

},

//镜像

mirrorProcess: function(context, canvasData) {

console.log( Canvas Filter process );

var tempCanvasData = 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 array      

var idx = (x + y * tempCanvasData.width) * 4;

var midx = (((tempCanvasData.width 1) x) + y * tempCanvasData.width) * 4;

 

// assign new pixel value      

canvasData.data[midx + 0] = tempCanvasData.data[idx + 0]; // Red channel      

canvasData.data[midx + 1] = tempCanvasData.data[idx + 1];; // Green channel      

canvasData.data[midx + 2] = tempCanvasData.data[idx + 2];; // Blue channel      

canvasData.data[midx + 3] = 255; // Alpha channel      

}

}

},

};

/script

 

/html

!

尊重原创，转载请注明来自：http://www.cnblogs.com/fsjohnhuang/p/4127888.html 

原创文章，作者：ItWorker，如若转载，请注明出处：https://blog.ytso.com/13859.html

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