几行代码，和几行代码，

CGRect rect=CGRectMake(_xstep*j, _ystep*i, _xstep, _ystep);

CGImageRef imageRef=CGImageCreateWithImageInRect([image CGImage],rect);

UIImage* elementImage=[UIImage imageWithCGImage:imageRef];

UIImageView*_imageView=[[UIImageView alloc] initWithImage:elementImage];

_imageView.frame=rect;

 

 UIGraphicsBeginImageContext(CGSizeMake(self.targetSize.width*scale, self.targetSize.height*scale));

  [self.sourceImage drawInRect:CGRectMake(-startX*scale, -startY*scale, imageViewSize.width*scale, imageViewSize.height*scale)];

  UIImage* image = UIGraphicsGetImageFromCurrentImageContext();