touch 的图片缩放 拖拽

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);  
        });  
    }  
};  

<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> 

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) { });