// 从view上截图  
    - (UIImage *)getImage {  
          
        UIGraphicsBeginImageContextWithOptions(CGSizeMake(150, 150), NO, 1.0);  //NO，YES 控制是否透明  
        [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];  
        UIImage *image = UIGraphicsGetImageFromCurrentImageContext();  
        UIGraphicsEndImageContext();  
        // 生成后的image  
          
        return image;  
    }  
      
    // 根据给定得图片，从其指定区域截取一张新得图片  
    -(UIImage *)getImageFromImage{  
        //大图bigImage  
        //定义myImageRect，截图的区域  
        CGRect myImageRect = CGRectMake(70, 10, 150, 150);  
        UIImage* bigImage= [UIImage imageNamed:@"mm.jpg"];  
        CGImageRef imageRef = bigImage.CGImage;  
        CGImageRef subImageRef = CGImageCreateWithImageInRect(imageRef, myImageRect);  
        CGSize size;  
        size.width = 150;  
        size.height = 150;  
        UIGraphicsBeginImageContext(size);  
        CGContextRef context = UIGraphicsGetCurrentContext();  
        CGContextDrawImage(context, myImageRect, subImageRef);  
        UIImage* smallImage = [UIImage imageWithCGImage:subImageRef];  
        UIGraphicsEndImageContext();  
        return smallImage;  
    }