jQuery插件jcrop+Fileapi完美实现图片上传+裁剪+预览的代码分享

    var el = $('input').get(0);
     
     seajs.use(['gallery/jcrop/0.9.12/jcrop.css','gallery/jcrop/0.9.12/jcrop.js'] ,function(){
     
    FileAPI.event.on(el, 'change', function (evt){
      var files = FileAPI.getFiles(evt); // Retrieve file list
 
      FileAPI.filterFiles(files, function (file, info){
        if( !/^image/.test(file.type)  ){
          alert('图片格式不正确');
          return false;
        }
        else if(file.size > 20 * FileAPI.MB){
          alert('图片必须小于20M');
           return false;
        }
        else{
          return true;
        }
        
      }, function (files, rejected){
        console.log(files);
         
        if( files.length ){
          var file = files[0];
           var img0 = FileAPI.Image(file);
           var img1 = FileAPI.Image(file);
           var ratio = 0;
          FileAPI.getInfo(file, function (err, info) {  //get image ratio
              if (!err) {
                if (info.width > info.height) {
                  ratio = info.width / 500;
                }
                else {
                  ratio = info.height / 500;
                }
              }
            });
 
            img0.resize(500, 500, 'max')   //place image and register jcrop
                .get(function(err, img) {
                  $('#img2').empty();
                  $('#img2').append($(img));
 
                  $('#img2').children().Jcrop({
                    aspectRatio: 1,
                    bgColor: 'rgba(0,0,0,0.4)',
                    onSelect: function(c) {
                      img1.matrix.sx = c.x * ratio;
                      img1.matrix.sy = c.y * ratio;
                      img1.matrix.sw = c.w * ratio;
                      img1.matrix.sh = c.h * ratio;
                      img1.matrix.dw = 500;
                      img1.matrix.dh = 500;
 
                      img1.get(function(err, img) {
                        // $('#img3').empty();
                        //   $('#img3').append($(img));
                        $('#img3').html($(img));
                      });
 
                    }
                  });
                });
                  $('#btn').on('click',function(){
                        FileAPI.upload({
//                          url: '/testUpFile/upFile',
                          // headers: { 'Content-Type': 'multipart/form-data' },
                          files: { images: img1 },
                          progress: function (evt){ /* ... */ },
                          complete: function (err, xhr){ /* ... */
                            //alert(xhr.responseText);
                            console.log(xhr);
                          }
                        });              
                  });
          }
        });
      });
  });

  
    
    
    
      
    
    
  
  
 
  
  
    

    
    

       
      
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