欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识!
您现在的位置是: 首页  >  IT编程

js特效教程(javascript特效代码大全)

程序员文章站 2023-11-24 10:00:58
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...

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 image

tempcontext = 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 = 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=*"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:

js特效教程(javascript特效代码大全)

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="default.css" rel="stylesheet" />
<script src="gloomyfishfilter.js"></scrip>
</head>
<body>
  <h1>html canvas image process - by gloomy fish</h1>
  <div id="svgcontainer">
    <div id="sourcediv">
      <img id="source" src="../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 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):

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 = 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
   * 浮雕效果
   */
  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
   *  雕刻效果
   * 
   * @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    
            }
    }
  },
};