touch.js 实现元素拖动、缩放与旋转手势交互

touch.js 手势交互功能概述

利用 touch.js 可以便捷地实现包括拖动、缩放及旋转在内的多种手势操作。该库提供了封装完善的脚本接口，简化了复杂手势逻辑的开发过程。

var cat = window.cat || {}; 
cat.touchjs = { 
  left: 0, 
  top: 0, 
  scaleVal: 1,  //缩放 
  rotateVal: 0,  //旋转 
  curStatus: 0,  //记录当前手势的状态, 0:拖动, 1:缩放, 2:旋转 
  //初始化 
  init: function ($targetObj, callback) { 
    touch.on($targetObj, 'touchstart', function (ev) { 
      cat.touchjs.curStatus = 0; 
      ev.preventDefault();//阻止默认事件 
    }); 
    if (!window.localStorage.cat_touchjs_data) 
      callback(0, 0, 1, 0); 
    else { 
      var jsonObj = JSON.parse(window.localStorage.cat_touchjs_data); 
      cat.touchjs.left = parseFloat(jsonObj.left), cat.touchjs.top = parseFloat(jsonObj.top), cat.touchjs.scaleVal = parseFloat(jsonObj.scale), cat.touchjs.rotateVal = parseFloat(jsonObj.rotate); 
      callback(cat.touchjs.left, cat.touchjs.top, cat.touchjs.scaleVal, cat.touchjs.rotateVal); 
    } 
  }, 
  //拖动 
  drag: function ($targetObj, callback) { 
    touch.on($targetObj, 'drag', function (ev) { 
      $targetObj.css("left", cat.touchjs.left + ev.x).css("top", cat.touchjs.top + ev.y); 
    }); 
    touch.on($targetObj, 'dragend', function (ev) { 
      cat.touchjs.left = cat.touchjs.left + ev.x; 
      cat.touchjs.top = cat.touchjs.top + ev.y; 
      callback(cat.touchjs.left, cat.touchjs.top); 
    }); 
  }, 
  //缩放 
  scale: function ($targetObj, callback) { 
    var initialScale = cat.touchjs.scaleVal || 1; 
    var currentScale; 
    touch.on($targetObj, 'pinch', function (ev) { 
      if (cat.touchjs.curStatus == 2) { 
        return; 
      } 
      cat.touchjs.curStatus = 1; 
      currentScale = ev.scale - 1; 
      currentScale = initialScale + currentScale; 
      cat.touchjs.scaleVal = currentScale; 
      var transformStyle = 'scale(' + cat.touchjs.scaleVal + ') rotate(' + cat.touchjs.rotateVal + 'deg)'; 
      $targetObj.css("transform", transformStyle).css("-webkit-transform", transformStyle); 
      callback(cat.touchjs.scaleVal); 
    }); 
    touch.on($targetObj, 'pinchend', function (ev) { 
      if (cat.touchjs.curStatus == 2) { 
        return; 
      } 
      initialScale = currentScale; 
      cat.touchjs.scaleVal = currentScale; 
      callback(cat.touchjs.scaleVal); 
    }); 
  }, 
  //旋转 
  rotate: function ($targetObj, callback) { 
    var angle = cat.touchjs.rotateVal || 0; 
    touch.on($targetObj, 'rotate', function (ev) { 
      if (cat.touchjs.curStatus == 1) { 
        return; 
      } 
      cat.touchjs.curStatus = 2; 
      var totalAngle = angle + ev.rotation; 
      if (ev.fingerStatus === 'end') { 
        angle = angle + ev.rotation; 
      } 
      cat.touchjs.rotateVal = totalAngle; 
      var transformStyle = 'scale(' + cat.touchjs.scaleVal + ') rotate(' + cat.touchjs.rotateVal + 'deg)'; 
      $targetObj.css("transform", transformStyle).css("-webkit-transform", transformStyle); 
      $targetObj.attr('data-rotate', cat.touchjs.rotateVal); 
      callback(cat.touchjs.rotateVal); 
    }); 
  } 
}; 

HTML 结构代码如下：

<div style="position:relative;width: 100%;height: 250px;overflow: hidden;border: 1px dashed #ff0000;"> 
 <img id="targetObj" style="position:relative;transform-origin:center" src="http://demo.somethingwhat.com/images/flower1.jpg" /> 
</div>

JavaScript 调用示例如下：

var $targetObj = $('#targetObj'); 
//初始化设置 
cat.touchjs.init($targetObj, function (left, top, scale, rotate) {}; 
//初始化拖动手势（不需要就注释掉） 
cat.touchjs.drag($targetObj, function (left, top) { }); 
//初始化缩放手势（不需要就注释掉） 
cat.touchjs.scale($targetObj, function (scale) { }); 
//初始化旋转手势（不需要就注释掉） 
cat.touchjs.rotate($targetObj, function (rotate) { }); 

总结与反馈

上述内容介绍了基于 touch.js 实现拖动、缩放及旋转手势的核心代码。希望这些信息能为您提供帮助。如有任何疑问，欢迎留言咨询，小编将及时回复。同时感谢对本站的支持！