ios 截屏

 UIImage *snapshot;
    CGImageRef cgScreen = UIGetScreenImage();
    if (cgScreen) {
        snapshot = [UIImage imageWithCGImage:cgScreen];
        CGImageRelease(cgScreen);
    }
    
    CGRect rect = CGRectMake(0,125, 640, 750);//创建要剪切的矩形框 这里你可以自己修改
    UIImage *res = [UIImage imageWithCGImage:CGImageCreateWithImageInRect([snapshot CGImage], rect)];
    
    NSLog(@"ssf:%@",res );
    _imageViewW.image = res;    //res 为截屏的图片