js 移动端查看图片的算法支持单指触摸拖动和双指触摸缩放

 <style>

    
     #find_picture{position:fixed;top:0;right:0;bottom:0;left:0;display:-webkit-box;-webkit-box-align:center;-webkit-box-pack:center;display:box;box-pack:center;box-align:center;-webkit-user-select:none;user-select:none}
    
     #find_picture_box{width:100%;height:100%;background-color:#000;}
    
     #control_picture{width:100%;height:100%;background-image:url("");background-position:center center;background-size:contain;background-repeat: no-repeat;}