前言

昨天看到一位簡(jiǎn)書(shū)作者的博客,寫(xiě)的是swift的版的模糊圖,正好我做的項(xiàng)目有這個(gè)需求,所以就翻譯了一版OC語(yǔ)言的

預(yù)覽圖

效果圖

#import "ViewController.h"

@interface ViewController ()
/** 展示圖片控件 */
@property (weak, nonatomic) IBOutlet UIImageView *imageview;

@property (weak, nonatomic) IBOutlet UIScrollView *scrollview;
/** 背景圖片 */
@property (strong, nonatomic) UIImageView *backgroundImageView;
/** 當(dāng)前圖片下標(biāo) */
@property (assign, nonatomic)NSInteger index;
@end

@implementation ViewController
- (IBAction)changeImage:(UIButton *)sender {
    // 點(diǎn)擊切換圖片 偏移量為0
    self.scrollview.contentOffset = CGPointZero;
    _index++;
    if (_index>5) {
        _index = 1;
    }
    [self changeImageWithIndex];
}

- (void)viewDidLoad {
    [super viewDidLoad];
    // 賦初值調(diào)用方法
    _index = 1;
    [self changeImageWithIndex];
    
 }
/** 切換圖片方法 */
- (void)changeImageWithIndex{
    [_imageview layoutIfNeeded];
    NSString *str = [NSString stringWithFormat:@"%ld",_index];
    self.imageview.image = [UIImage imageNamed:str];
    // 調(diào)用高斯模糊方法
    [self creatBlurBackgound:[UIImage imageNamed:str] view:_imageview blurRadius:50];
}
- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
- (void)creatBlurBackgound:(UIImage *)image view:(UIView *)view blurRadius:(CGFloat)blurRadius{
    // 創(chuàng)建屬性
    CIImage *cimage = [[CIImage alloc] initWithImage:image];
    // 濾鏡效果 高斯模糊
    CIFilter *filter = [CIFilter filterWithName:@"CIGaussianBlur"];
    // 指定過(guò)濾照片
    [filter setValue:cimage forKey:kCIInputImageKey];
    // 模糊值
    NSNumber *number = [NSNumber numberWithFloat:blurRadius];
    // 指定模糊值
    [filter setValue:number forKey:@"inputRadius"];
    // 生成圖片
    CIContext *context = [CIContext contextWithOptions:nil];
    // 創(chuàng)建輸出
    CIImage *result = [filter valueForKey:kCIOutputImageKey];
    // 下面這一行的代碼耗費(fèi)時(shí)間內(nèi)存最多,可以開(kāi)辟線程處理然后回調(diào)主線程給imageView賦值
    CGImageRef cgimage = [context createCGImage:result fromRect:result.extent];
    UIImage *imagea = [UIImage imageWithCGImage:cgimage];

    
    // 賦值圖片
    self.backgroundImageView.image = imagea;
    
}
// 懶加載
- (UIImageView *)backgroundImageView{
    if (!_backgroundImageView) {
        // 獲取view寬高
        CGFloat w = self.view.frame.size.width;
        CGFloat h = self.view.frame.size.height;
        // 4倍縮放
        _backgroundImageView = [[UIImageView alloc] initWithFrame:CGRectMake(-w/2, -h/2, w, 2*h)];
        // 等比例填充模式
        _backgroundImageView.contentMode = UIViewContentModeScaleAspectFill;
        // 對(duì)其
        _backgroundImageView.autoresizingMask = UIViewAutoresizingFlexibleWidth |UIViewAutoresizingFlexibleHeight;
        // 添加到view上
        [self.view insertSubview:_backgroundImageView belowSubview:_scrollview];
    }
    return _backgroundImageView;
}
@end

效果圖

高斯模糊圖

上代碼

scrollView和 button 都是為了換圖片看效果才加的,如果只需要模糊效果可以只創(chuàng)建一個(gè)imageView
gitHub:https://github.com/Lafree317/iOS-GaussImage
swift版博客地址:http://www.itdecent.cn/p/c9083a105921