1.从UIImage中取

 

UIImage* newimage = [UIImage imageWithCGImage:CGImageCreateWithImageInRect([image CGImage], rect)];

 

2.从view截取

 

    UIGraphicsBeginImageContext(CGSizeMake(self.view.bounds.size.width, self.view.bounds.size.height - 20));

    [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];     UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();     UIGraphicsEndImageContext();