ios开发中常常用到的毛玻璃效果实现方法
iOS8以后使用系统里的UIBlurEffect可以实现,UIBlurEffect继承自UIVisualEffect
UIBlurEffectStyle有三个值,UIBlurEffectStyleLight , UIBlurEffectStyleExtraLight , UIBlurEffectStyleDark,可以控制毛玻璃的效果.
UIBlurEffect *effect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleDark];
UIVisualEffectView *effectView = [[UIVisualEffectView alloc] initWithEffect:effect];
//必须给effcetView的frame赋值,因为UIVisualEffectView是一个加到UIIamgeView上的子视图.
effectView.frame = _imageView.bounds;
[self.imageView addSubview:effectView];
UIVibrancyEffect也继承自UIVisualEffect类,可以用来设置一些特殊的效果.代码如下
UIBlurEffect *effect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleLight];
UIVisualEffectView *effectView = [[UIVisualEffectView alloc] initWithEffect:effect];
effectView.frame = _imageView.bounds;
UIVibrancyEffect *viBrancyeffect = [UIVibrancyEffect effectForBlurEffect:effect];
UIVisualEffectView *vibrancyEffectView = [[UIVisualEffectView alloc] initWithEffect:viBrancyeffect];
vibrancyEffectView.frame = CGRectMake(100, 0, 200, 200);
UILabel *lbl = [[UILabel alloc] init];
lbl.text = @"测试Label";
lbl.font = [UIFont systemFontOfSize:25];
lbl.frame = CGRectMake(0, 0, 200, 200);
[vibrancyEffectView.contentView addSubview:lbl];
[effectView.contentView addSubview:vibrancyEffectView];
[self.imageView addSubview:effectView];
但是这种毛玻璃效果不能很好的控制模糊效果,可以alpha属性控制并不完美.
效果如下:
IMG_0142.jpg
使用系统CoreImage中的滤镜产生毛玻璃效果
原理是给图片添加滤镜,这种方式相比上面更为可控,下面介绍一下系统滤镜中支持的毛玻璃效果
先简要介绍一下系统滤镜CIFilter的使用
CIfilter中有一个专门用于毛玻璃效果的Category : kCICategoryBlur
使用下面的代码可以打印出这个分类下的滤镜
NSArray *filters = [CIFilter filterNamesInCategory:kCICategoryBlur];
可以得到结果
** CIBoxBlur,**
** CIDiscBlur,**
** CIGaussianBlur,**
** CIMaskedVariableBlur,**
** CIMedianFilter,**
** CIMotionBlur,**
** CINoiseReduction,**
** CIZoomBlur**
我们使用最常见的高斯模糊 (Gaussian Blur) 来进行举例
NSArray *inputKeys = filter.inputKeys;
可以得到这个滤镜支持两个输入属性,分别是inputImage,inputRadius
其中inputImage指你需要添加滤镜效果的图片,inputRadius指进行高斯模糊的程度
设置属性的方式有两种
一种是直接通过NSDictionary赋值
CIImage *testCIImage = [CIImage imageWithCGImage:[UIImage imageNamed:@"testImg.jpg"].CGImage];
NSDictionary *filterAttDict = @{@"inputImage" : testCIImage
,@"inputRadius" : [NSNumber numberWithDouble:5.0f]};
CIFilter *filter = [CIFilter filterWithName:@"CIGaussianBlur" withInputParameters:filterAttDict];
CIImage *outPutCIImage = [filter outputImage];
CIContext *ciContext = [CIContext contextWithOptions:nil];
CGImageRef cgImage = [ciContext createCGImage:outPutCIImage fromRect:outPutCIImage.extent];
UIImage *resImage = [UIImage imageWithCGImage:cgImage];
另一种是通过kvc方法赋值
CIFilter *filter = [CIFilter filterWithName:@"CIGaussianBlur"];
CIImage *testCIImage = [CIImage imageWithCGImage:[UIImage imageNamed:@"testImg.jpg"].CGImage];
[filter setValue:testCIImage forKeyPath:kCIInputImageKey];
[filter setValue:@50 forKeyPath:kCIInputRadiusKey];
CIImage *outPutCIImage = [filter outputImage];
CIContext *ciContext = [CIContext contextWithOptions:nil];
CGImageRef cgImage = [ciContext createCGImage:outPutCIImage fromRect:outPutCIImage.extent];
UIImage *resImage = [UIImage imageWithCGImage:cgImage];
发现一个写的比较详细的博客,可以参考 http://www.jianshu.com/p/d115836ed3fa
