I tried my hand at it, implemented six simple and common HTML5 Canvas special effects filters, and encapsulated them into a pure JavaScript callable API file gloomyfishfilter.js. The supported special effect filters are:
1. Inverse color
2. Gray tone
3. Blur
4. Embossing
5. Engraving
6 .Mirror

Explanation of filter principle:
1. Inverse color: Get a pixel RGB value r, g, b and the new RGB value is (255-r, 255 -g, 255-b)
2. Gray tone: Get a pixel RGB value r, g, b and the new RGB value is

Copy code The code is as follows:

 
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. Blur: based on a 5*5 volume Core
4. Relief and engraving:
Based on the difference between the RGB value of the previous pixel of the current pixel and the RGB value of the next pixel plus 128
5. Mirror: simulates the object in the mirror the corresponding effect.
Miscellaneous preparation
1. How to obtain the Canvas 2d context object

Copy code The code is as follows:

 
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 image 
tempContext = canvas.getContext ("2d"); 

2. How to draw a DOM img object into a Canvas object

Copy code The code is as follows:

 
var source = document.getElementById("source"); 
tempContext.drawImage(source, 0, 0, canvas.width,canvas.height); 

3. How to get pixel data from Canvas object

Copy code The code is as follows:

 
var canvas = document.getElementById("target"); 
varlen = canvas.width * canvas.height * 4; 
var canvasData = tempContext.getImageData(0, 0, canvas.width , canvas.height); 
var binaryData = canvasData.data; 

4. How to implement mouse Click event binding on DOM objects

Copy code The code is as follows:

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

5. How to call the implemented gfilter API to complete the filter function

Copy the code The code is as follows:

 
 //Import API file
gfilter.colorInvertProcess(binaryData, len); //Call API 

6. Browser support: passed the test on IE, FF, and Chrome. Support on IE is achieved through the following tags:

Copy code The code is as follows:

Effect demonstration :
Examples of implementing six special effects filters in HTML5 Canvas using pure JavaScript_javascript skills

Application source code:
CSS part:

Copy code The code is as follows:

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

HTML source code in filter1.html:

Copy code The code is as follows:

Canvas Filter Demo

HTML Canvas Image Process - By Gloomy Fish

filter1.html中JavaScript源代码：

复制代码代码如下:

 
var tempContext = null; // global variable 2d context 
window.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 image 
tempContext = canvas.getContext("2d"); 
tempContext.drawImage(source, 0, 0, canvas.width, canvas.height); 

// initialization actions 
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"); 
// bind mouse click event 
bindButtonEvent(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 = tempContext.getImageData(0, 0, canvas.width, canvas.height); 
var binaryData = canvasData.data; 

// Processing all the pixels 
gfilter.colorInvertProcess(binaryData, len); 
// Copying back canvas data to canvas 
tempContext.putImageData(canvasData, 0, 0); 
} 

function adjustColor() { 
var canvas = document.getElementById("target"); 
var len = canvas.width * canvas.height * 4; 
var canvasData = tempContext.getImageData(0, 0, canvas.width, canvas.height); 
var binaryData = canvasData.data; 

// Processing all the pixels 
gfilter.colorAdjustProcess(binaryData, len); 
// Copying back canvas data to canvas 
tempContext.putImageData(canvasData, 0, 0); 
} 

function blurImage() 
{ 
var canvas = document.getElementById("target"); 
var len = canvas.width * canvas.height * 4; 
var canvasData = tempContext.getImageData(0, 0, canvas.width, canvas.height); 

// Processing all the pixels 
gfilter.blurProcess(tempContext, canvasData); 
// Copying back canvas data to canvas 
tempContext.putImageData(canvasData, 0, 0); 
} 

function fudiaoImage() 
{ 
var canvas = document.getElementById("target"); 
var len = canvas.width * canvas.height * 4; 
var canvasData = tempContext.getImageData(0, 0, canvas.width, canvas.height); 

// Processing all the pixels 
gfilter.reliefProcess(tempContext, canvasData); 
// Copying back canvas data to canvas 
tempContext.putImageData(canvasData, 0, 0); 
} 

function kediaoImage() 
{ 
var canvas = document.getElementById("target"); 
var len = canvas.width * canvas.height * 4; 
var canvasData = tempContext.getImageData(0, 0, canvas.width, canvas.height); 

// Processing all the pixels 
gfilter.diaokeProcess(tempContext, canvasData); 
// Copying back canvas data to canvas 
tempContext.putImageData(canvasData, 0, 0); 
} 

function mirrorImage() 
{ 
var canvas = document.getElementById("target"); 
var len = canvas.width * canvas.height * 4; 
var canvasData = tempContext.getImageData(0, 0, canvas.width, canvas.height); 

// Processing all the pixels 
gfilter.mirrorProcess(tempContext, canvasData); 
// Copying back canvas data to canvas 
tempContext.putImageData(canvasData, 0, 0); 
} 

滤镜源代码(gloomyfishfilter.js)：

复制代码代码如下:

 
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 (blur effect) 
* 
* @param context 
* @param canvasData 
*/ 
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 
} 
} 
}, 

/**
* after pixel value - before pixel value 128 
* Relief effect 
*/ 
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 
} 
} 
}, 

/**
* before pixel value - after pixel value 128 
* Carving effect 
* 
* @param canvasData 
*/ 
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 
} 
} 
}, 

/**
* mirror reflect 
* 
* @param context 
* @param canvasData 
*/ 
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 
} 
} 
}, 
}; 