<view class="container" style="height:{{screenHeight}}px;" >

    <view class="cnt">

        <image class="image-style" src="../uploads/2.jpg" style="width:

        {{imgwidth}}px;height:{{imgheight}}px;"bindtouchstart="startEvent"

         bindtouchmove="moveEvent"bindload="imageLoad"animation="

         {{animationData}}"bindtouchend="endEvent">

        </image>

    </view>

</view>

.container {

    box-sizing:border-box;

    padding:1rem;

}

.cnt{

    width:100%;

    height:70%;

    border: 1px solid #ccc;

    position:relative;

    overflow: hidden;

    z-index:9999;

}

.image-style{

    -webkit-transform:translate(-38px,0px); 

}

var app = getApp()

Page({

    data: {

        imgwidth:0,

        imgheight:0,

        animationData: {},

        movex:0,

        movey:0,

        x:0,

        y:0,

    },

    onLoad: function() {

         // 页面初始化 options为页面跳转所带来的参数

        var _this = this;

        wx.getSystemInfo({

            success: function(res) {

                _this.setData({

                    screenHeight: res.windowHeight,

                    screenWidth: res.windowWidth,

                });

            }

        });

    },

    onReady:function(){

        // 页面渲染完成

        //实例化一个动画

        this.animation = wx.createAnimation({

            duration: 1000,

            timingFunction: 'linear',//均匀

            transformOrigin: "left top 0px",

        })

    },

    imageLoad: function(e) { 

        var _this=this;

        //1.框的宽高

        var cnt_offetw=_this.data.screenWidth-38,

            cnt_offeth=(_this.data.screenHeight-38)*0.7;

        //2.获取图片真实宽度

        var $width=e.detail.width,    //获取图片真实宽度 

            $height=e.detail.height, 

            ratio=$width/$height;   //图片的真实宽高比例

        //3.进行判断:当图片小于框时候，图片大小等于框大小，当大于框的时候，则成比例呈现

        var viewWidth=_this.data.screenWidth;           //设置图片固定宽度值， 

        var viewHeight=parseInt(viewWidth/ratio);    //计算的高度值

        if (viewHeight< cnt_offeth) {

            viewHeight=cnt_offeth;

        }

        _this.setData({

            imgwidth:viewWidth, 

            imgheight:viewHeight,

            cnt_boxw:cnt_offetw,

            cnt_boxh:cnt_offeth,

        })

    },

    startEvent:function(e){

        //1.获取鼠标点击下去的

        this.setData({

            startx: e.touches[0].pageX,

            starty: e.touches[0].pageY

        })

    },

    moveEvent: function(e) {

        var _this=this;

        //2.鼠标移动的位置

        var pageX = e.touches[0].pageX;

        var pageY = e.touches[0].pageY;

        var x,y;

        //3.记住初始化图片x,y

        var endx=_this.data.x,endy=_this.data.y;

        //4.判断

        var w_x=_this.data.imgwidth-_this.data.cnt_boxw;//x拖拽值：图片宽-框的宽

        var h_y=parseInt(_this.data.imgheight-_this.data.cnt_boxh);//y拖拽值：图片高-框高

        var DistanceX = pageX - _this.data.startx;//x:当鼠标点击到移动的点之间的距离

        var DistanceY =pageY - _this.data.starty;//y:当鼠标点击到移动的点之间的距离

        if (DistanceX>0){

            //往右移动 如果当前的值大于等于0时则不移动，否则当前值加上鼠标拖拽的距离

            if (endx >= 0) {

                x = 0;

            } else {

                x = endx + DistanceX;

            }

        }else{

            //往左移动:x拖拽值大于等于当前的值，说明已经到边上了，就等于拖拽值，否则当前的值加上鼠标拖拽的距离

            if (w_x >= endx) {

                x = -w_x;

            } else {

                x = endx + DistanceX;

            }

        }

        if (DistanceY>0){

            //往下移动:如果当前的值大于等于0时则不移动，否则当前值加上鼠标拖拽的距离

            if(endy>=0){

                y =0;

            }else{

                y = endy + DistanceY;

            }

        }else{

            //往上移动:y拖拽值大于等于当前的值，说明已经到边上了，就等于拖拽值，否则当前的值加上鼠标拖拽的距离

            if(-endy==h_y||-endy>h_y){

                y=-h_y;

                console.log("da0")

            }else{

                y=endy+DistanceY;

                console.log("da 1")

            }

        }

        setTimeout(function() {

            _this.animation.translate(x, y).step();

            _this.setData({

                animationData: this.animation.export()

            })

        }.bind(this), 0)

        _this.setData({

            x:x,

            y:y,

        })

        endx=x;endy=y;//记住这次的图片移动的范围

        _this.data.startx=pageX;_this.data.starty=pageY;// 每移动一次把上一次的点作为原点

    },

    endEvent:function(){

        clearTimeout(function(){

            this.animation.translate(this.data.x,this.data.y).step();

            this.setData({

                animationData: this.animation.export()

            })

        });

    }

})