iOS View转换成清晰的image图片

-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    [self.view.subviews makeObjectsPerformSelector:@selector(removeFromSuperview)];
    UIView *BGView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 320, 110+150+150)];
    BGView.backgroundColor = [UIColor whiteColor];
    
    UIImageView *topImageView = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 320, 110)];
    topImageView.image = [UIImage imageNamed:@"topImage.png"];
    [BGView addSubview:topImageView];
    
    UILabel *textLabel = [[UILabel alloc]initWithFrame:CGRectMake(20, 110+20, 320-40, 150-40)];
    textLabel.numberOfLines = 0;
    textLabel.text = @"下面方法，第一个参数表示区域大小。第二个参数表示是否是非透明的。如果需要显示半透明效果，需要传NO，否则传YES。第三个参数就是屏幕密度了，关键就是第三个参数";
//    textLabel.backgroundColor = [UIColor whiteColor];
    textLabel.textColor = [UIColor blueColor];
    [BGView addSubview:textLabel];
    
    UIImageView *bottomImageView = [[UIImageView alloc]initWithFrame:CGRectMake(0, 110+150, 320, 150)];
    bottomImageView.image = [UIImage imageNamed:@"bottomImage.png"];
    [BGView addSubview:bottomImageView];
    

    UIImageView *testImageView = [[UIImageView alloc]initWithFrame:CGRectMake(20, 50, 320, 110+150+150)];
    testImageView.image = [self makeImageWithView:BGView withSize:BGView.frame.size];;
    [self.view addSubview:testImageView];
    
}


#pragma mark 生成image
- (UIImage *)makeImageWithView:(UIView *)view withSize:(CGSize)size
{
    
    // 下面方法，第一个参数表示区域大小。第二个参数表示是否是非透明的。如果需要显示半透明效果，需要传NO，否则传YES。第三个参数就是屏幕密度了，关键就是第三个参数 [UIScreen mainScreen].scale。
    UIGraphicsBeginImageContextWithOptions(size, YES, [UIScreen mainScreen].scale);
    [view.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
    
}