ios实现磨玻璃在各个系统上都有所不同，新系统总会有比旧系统更好的方式去实现毛玻璃

iOS 6及以下系统，可以生成一张模糊效果的图片实现
//生成一张毛玻璃图片

• (UIImage)blur:(UIImage)theImage

{

CIContext *context = [CIContext contextWithOptions:nil];

CIImage *inputImage = [CIImage imageWithCGImage:theImage.CGImage];

CIFilter *filter = [CIFilter filterWithName:@"CIGaussianBlur"];

[filter setValue:inputImage forKey:kCIInputImageKey];

[filter setValue:[NSNumber numberWithFloat:6.0f] forKey:@"inputRadius"];//模糊度

CIImage *result = [filter valueForKey:kCIOutputImageKey];

CGImageRef cgImage = [context createCGImage:result fromRect:[inputImage extent]];

UIImage *returnImage = [UIImage imageWithCGImage:cgImage];

CGImageRelease(cgImage);

return returnImage;

}

iOS 7可以用uitoolbar实现毛玻璃效果，代码如下：

UIToolbar *toolBar = [[UIToolbar alloc] initWithFrame:self.view.bounds];

toolBar.barStyle = UIBarStyleBlackTranslucent;

[toolBar setBackgroundImage:self.image.image forToolbarPosition:UIBarPositionBottom barMetrics:UIBarMetricsDefaultPrompt];

 [self.view addSubview:toolBar];

然而iOS 8有了更好的api UIVisualEffectView

UIVisualEffect *blurEffect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleLight];

UIVisualEffectView *visualEffectView = [[UIVisualEffectView alloc] initWithEffect:blurEffect];

visualEffectView.frame = self.image.bounds;

visualEffectView.alpha = 0.7;//模糊程度

        [self.image addSubview:visualEffectView];