iOS模糊效果的实现方法

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本文实例为大家分享了iOS模糊效果的3种方法，供大家参考，具体内容如下

方案一：利用系统的CoreImage(滤镜)

重点理解CIImage,CIFilter,CIContext,CGImageRef

滤镜处理的过程比较慢,会造成加载图片缓慢的现象(等一会才看到图片),尽量放到子线程执行

- (void)viewDidLoad {
 [super viewDidLoad];

 // 加载一张图片
 UIImage *image = [UIImage imageNamed:@"che"];

 /**************CoreImage部分**************/

 // 1.创建CIImage
 CIImage *ciImage = [[CIImage alloc] initWithImage:image];

 // 2.创建滤镜CIFilter
 CIFilter *blurFilter = [CIFilter filterWithName:@"CIGaussianBlur"];

 // 2.1.将CIImage输入到滤镜中
 [blurFilter setValue:ciImage forKey:kCIInputImageKey];

 // 可以通过该方法查看我们可以设置的值(如模糊度等)
 NSLog(@"%@", [blurFilter attributes]);

 // 2.2设置模糊度
 [blurFilter setValue:@(2) forKey:@"inputRadius"];

 // 2.3将处理好的图片输出
 CIImage *outCiImage = [blurFilter valueForKey:kCIOutputImageKey];

 // 3.CIContext(option参数为nil代表用CPU渲染,若想用GPU渲染请查看此参数)
 CIContext *context = [CIContext contextWithOptions:nil];

 // 4.获取CGImage句柄
 CGImageRef outCGImage = [context createCGImage:outCiImage fromRect:[outCiImage extent]];

 // 5.获取最终的图片
 UIImage *blurImage = [UIImage imageWithCGImage:outCGImage];

 // 6.释放CGImage
 CGImageRelease(outCGImage);
 /*****************************************/

 UIImageView *imageV = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 750 / 2, 1334 / 2)];
 imageV.image = blurImage;
 imageV.center = self.view.center;
 [self.view addSubview:imageV];

}

方案二：利用UIImage+ImageEffects分类

将UIImage+ImageEffects.h和UIImage+ImageEffects.m文件加载进工程
包含UIImage+ImageEffects.h
UIImage+ImageEffects文件路径

#import "ViewController.h"

#import "UIImage+ImageEffects.h"
- (void)viewDidLoad {
 [super viewDidLoad];

 // 原始图片
 UIImage *sourceImage = [UIImage imageNamed:@"che"];

 // 对图片进行模糊处理
 UIImage *blurImage = [sourceImage blurImageWithRadius:10];

 // 加载模糊处理后的图片
 UIImageView *imageV = [[UIImageView alloc] initWithImage:blurImage];
 [self.view addSubview:imageV];

}

方案三：利用UIVisualEffectView(iOS8)

#import "ViewController.h"

@interface ViewController ()

/** 背景 */
@property (nonatomic, strong) UIScrollView *scrollView;

@end

@implementation ViewController

- (void)viewDidLoad {
 [super viewDidLoad];

 // 添加展示的背景,用于显示动态模糊(背景能够滚动,便于查看动态的模糊)
 self.scrollView = [[UIScrollView alloc] initWithFrame:self.view.bounds];
 UIImageView *imageV = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"fengjing"]];
 self.scrollView.contentSize = imageV.image.size;
 self.scrollView.bounces = NO;
 [self.scrollView addSubview:imageV];
 [self.view addSubview:self.scrollView];

 /***************添加模糊效果***************/
 // 1.创建模糊view
 UIVisualEffectView *effectView = [[UIVisualEffectView alloc] initWithEffect:[UIBlurEffect effectWithStyle:UIBlurEffectStyleLight]];

 // 2.设定模糊View的尺寸
 effectView.frame = CGRectMake(0, 100, 375, 200);

 // 3.添加到view当中
 [self.view addSubview:effectView];



 /******************添加显示文本******************/
 UILabel *label = [[UILabel alloc] initWithFrame:effectView.bounds];
 label.text = @"模糊效果";
 label.font = [UIFont systemFontOfSize:40];
 label.textAlignment = NSTextAlignmentCenter;

 /****************添加模糊效果的子view****************/
 // 1.创建出子模糊view
 UIVisualEffectView *subEffectView = [[UIVisualEffectView alloc] initWithEffect:[UIVibrancyEffect effectForBlurEffect:(UIBlurEffect *)effectView.effect]];

 // 2.设置子模糊view的尺寸
 subEffectView.frame = effectView.bounds;

 // 3.将子模糊view添加到effectView的contentView上才能显示
 [effectView.contentView addSubview:subEffectView];

 // 4.添加要显示的view来达到特殊效果
 [subEffectView.contentView addSubview:label];

}

@end

效果图：