应用程序源代码：
CSS部分：

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

WBOYOriginal: 2016-05-16 17:30:561043browse

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

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