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原生JS实现图片网格式渐显、渐隐效果

2017年12月12日  | 移动技术网IT编程  | 我要评论

先给出效果图:

  写的小组件支持图片的渐显、渐隐,并且可以是有序、随机两种方式。

  我采用的原型是属性写在构造函数内,方法写在原型对象内。方法写构造函数内有个问题,就是每次调用这个方法就相当于重新实例化一次,举个粟子:

  实现网格效果的原理上是将读取图片的宽高,按照设定的参数,分成等高宽的网格(我用的span标签表示的网格),网格利用定位铺满整个图片,每个网格的背景图都是原图片,原理同sprite,利用background-position属性改变显示区域。接下来就是按照设定的顺序实现渐显或渐隐。渐显或渐隐用的是js的animation属性和css3的animation属性在属性值上有所区别,这次使用也才知道js的animation属性里有个animationfillmode(规定当动画不播放时(当动画完成时,或当动画有一个延迟未开始播放时),要应用到元素的样式。)属性值。

  我绑定的事件是点击,完全可以用其他事件或页面加载触发。我的代码稍加改动就可以实现网格式轮播图。

  下面给出源代码:

<!doctype html>
<head>
<title>网格效果</title>
<style>
  @charset "utf-8";
  /*css reset*/
  html{font-family:"helvetica neue",helvetica,stheiti,sans-serif;-webkit-text-size-adjust:100%;-moz-text-size-adjust:100%;-ms-text-size-adjust:100%;}
  body{-webkit-overflow-scrolling:touch;margin:0;}
  ul{margin:0;padding:0;list-style:none;outline:none;}
  dl,dd{margin:0;}
  a{display:inline-block;margin:0;padding:0;text-decoration:none;background:transparent;outline:none;color:#000;}
  a:link,a:visited,a:hover,a:active{text-decoration:none;color:currentcolor;}
  a,dt,dd{-webkit-touch-callout:none;-webkit-tap-highlight-color:transparent;}
  img{border:0;}
  p{margin:0;}
  input,button,select,textarea{margin:0;padding:0;border:0;outline:0;background-color:transparent;}
  /*css*/
  .origin-pic {
    display: inline-block;
    width: 200px;
    height: 200px;
  }
  .grid-area {
    display: inline-block;
    position: relative;
    width: 200px;
    height: 200px;
  }
  .grid {
    position: absolute;
  }
  #img1 {
    opacity: 1;
    width: 200px;
    height: 200px;
  }
  @keyframes fadeout{
    0% {opacity: 1}
    100% {opacity: 0}
  }
  @keyframes fadein{
    0% {opacity: 0}
    100% {opacity: 1}
  }
</style>
</head>
<body>
<div>
  <img class="origin-pic" src="./pic.jpg" />
</div>
<div id="grid_area" class="grid-area">
  <img id="img1" src="./pic.jpg" />
</div>
<script>
var gridsetting = {
  'cell': 10, // 行、列数量
  'mode': 'fadeout', // 备选参数: fadeout, fadein
  'sort': 'random', // 备选参数: inturn, random
  'num': 1, // 每次发生动作的网格数,目前只支持1
  complete: function() { // 事件完成时的回调函数
    console.log('ok!');
  }
};
var img1 = document.getelementbyid('img1');
(function(doc, setting, ele) {
  var defaults = {
    'speed': 20,
  };
  function grid(ele) {
    this.ele = ele;
    this.settings = object.assign({}, setting, defaults);
  }
  grid.prototype = {
    constructor: grid,
    // 构建ui
    _create: function() {
      var img = this.ele,
        settings = this.settings,
        cell = settings.cell,
        imgwidth = img.width,
        imgheight = img.height,
        gridwidth = imgwidth / cell, // 每个网格宽度
        gridheight = imgheight / cell, // 每个网格高度
        currenttop = 0,
        currentleft = 0,
        fragment = doc.createdocumentfragment(),
        i = 0,
        gridarr = [];
      img.style.display = 'none';
      for (; i < cell * cell; i++) {
        var spannode = doc.createelement('span');
        spannode.setattribute('id', i);
        spannode.style.csstext +=  'position: absolute;' +
                      'top: ' + currenttop + 'px;' +
                      'left: ' + currentleft + 'px;' +
                      'margin: 0;' +
                      'padding: 0;' +
                      'width: ' + gridwidth + 'px;' +
                      'height: ' + gridheight + 'px;' +
                      'opacity:' + settings.opacity + ';' +
                      'background: url('+ img.src + ');' +
                      'background-size: ' + imgwidth + 'px ' + imgheight + 'px;' +
                      'background-position: -' + currentleft + 'px -' + currenttop + 'px;';
        if (currentleft < (imgwidth - gridwidth)) {
          currentleft += gridwidth;
        } else {
          currentleft = 0;
          currenttop += gridheight;
        }
        fragment.append(spannode);
        gridarr.push(i);
      }
      this.gridarr = gridarr;
      doc.getelementbyid('grid_area').append(fragment);
    },
    // 渐显、渐隐
    _fade: function() {
      var gridarr = this.gridarr,
        clonearr = gridarr.slice(0),
        length = gridarr.length,
        settings = this.settings,
        sort = settings.sort,
        i = 0;
      switch(settings.mode) {
        case 'fadeout':
          if (sort == 'inturn') {
            // 按顺序渐隐
            var timer = setinterval(function() {
              doc.getelementbyid(gridarr[i]).style.animation = "fadeout 1s forwards";
              i++;
              if (i >= settings.cell * settings.cell) {
                clearinterval(timer);
                settings.complete();
              }
            }, settings.speed)
          } else if (sort == 'random') {
            // 随机渐隐
            var timer = setinterval(function() {
              i = clonearr.splice(math.random() * length--, 1);
              doc.getelementbyid(gridarr[i]).style.animation = "fadeout 1s forwards";
              if (length == 0) {
                clearinterval(timer);
                settings.complete();
              }
            }, settings.speed)
          }
          break;
        case 'fadein':
          if (sort == 'inturn') {
            // 按顺序渐渐显
            var timer = setinterval(function() {
              doc.getelementbyid(gridarr[i]).style.animation = "fadein 1s forwards";
              i++;
              if (i >= settings.cell * settings.cell) {
                clearinterval(timer);
                settings.complete();
              }
            }, settings.speed)
          } else if (sort == 'random') {
            // 随机渐显
            var timer = setinterval(function() {
              i = clonearr.splice(math.random() * length--, 1);
              doc.getelementbyid(gridarr[i]).style.animation = "fadein 1s forwards";
              if (length == 0) {
                clearinterval(timer);
                settings.complete();
              }
            }, settings.speed)
          }
          break;
        default:
          console.log('配置错误!');
      }
    },
    _checkmode: function() {
      if (this.settings.mode == 'fadein') {
        this.settings.opacity = 0;
      } else {
        this.settings.opacity = 1;
      }
    },
  };
  var gridarea = doc.getelementbyid('grid_area');
  gridarea.addeventlistener('click', function() {
    var event = new grid(ele);
    event._checkmode();
    event._create();
    event._fade();
  }, false);
})(document, gridsetting, img1);
</script>
</body>
</html>

以上所述是小编给大家介绍的原生js实现图片网格式渐显、渐隐效果,希望对大家有所帮助

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