by : http://cocacola-ty.github.io

處理過程

1. 讀取圖片

   1. 讀取UIImage類型圖片

   2. 將UIImage轉(zhuǎn)為NSData

   3. 根據(jù)NSData轉(zhuǎn)為CIImage

2. 處理濾鏡

   1. 創(chuàng)建濾鏡轴踱。根據(jù)濾鏡名稱初始化一個濾鏡

   2. 設(shè)置濾鏡參數(shù)

   3. 設(shè)置濾鏡圖片輸入源事秀，即設(shè)置濾鏡的inputImage參數(shù)

3. 處理進(jìn)行過濾鏡的圖片

   1. 獲取CIContext业踢，通過該對象將濾鏡的輸出圖像進(jìn)行處理

   2. 通過CIContext對象獲取濾鏡的輸出對象并將圖像轉(zhuǎn)換為CGImage

   3. 將CGImage轉(zhuǎn)換為UIImage

主要類

• CIContext: Core Image處理上下文，圖像處理在該類完成

• CIFilter：濾鏡類榄棵，定義各種濾鏡的屬性汹胃。各種濾鏡都屬于該類

• CIImage：保存圖像數(shù)據(jù)

實(shí)例

        /******讀取圖片部分******/
    // 讀取圖片
    NSString *path = [[NSBundle mainBundle] pathForResource:@"2" ofType:@"jpg"];
    UIImage *image = [UIImage imageWithContentsOfFile:path];
    
    // 將UIImage轉(zhuǎn)CIImage
    NSData *data = UIImagePNGRepresentation(image);
    CIImage *inputImage = [CIImage imageWithData:data];
    

    /******處理濾鏡部分******/
    // 初始化進(jìn)行濾鏡的顏色
    CIColor *sepiaColor = [CIColor colorWithRed:0.76 green:0.65 blue:0.54];
    
    // 通過濾鏡名稱創(chuàng)建濾鏡 初始化濾鏡參數(shù)
    CIFilter *monochromeFilter = [CIFilter filterWithName:@"CIColorMonochrome" withInputParameters:@{@"inputColor":sepiaColor,@"inputIntensity":@1.0}];
    // 設(shè)置濾鏡的輸入圖像
    [monochromeFilter setValue:inputImage forKey:@"inputImage"];
    
    // 根據(jù)濾鏡名稱創(chuàng)建濾鏡 初始化濾鏡基本參數(shù)
    CIFilter *vinFilter = [CIFilter filterWithName:@"CIVignette" withInputParameters:@{@"inputRadius":@1.75,@"inputIntensity":@1.0}];
    // 以經(jīng)過上一個濾鏡處理的圖像作為本次濾鏡的輸入圖像
    [vinFilter setValue:monochromeFilter.outputImage forKey:@"inputImage"];
    
    // 獲取經(jīng)過兩次濾鏡的圖像
    CIImage *outputImage = vinFilter.outputImage;
    
    // 創(chuàng)建高斯模糊濾鏡
    CIFilter *blur = [CIFilter filterWithName:@"CIGaussianBlur" withInputParameters:@{@"inputRadius":@40}];
    [blur setValue:inputImage forKey:@"inputImage"];
    

    /******處理濾鏡之后圖片部分******/
    // 將CIImage轉(zhuǎn)換為CGImage 再轉(zhuǎn)為UIImage
    CIContext *context = [CIContext contextWithOptions:nil];
    struct CGImage *cgImage = [context createCGImage:blur.outputImage fromRect:inputImage.extent];
    
    UIImage *outputUIImage = [UIImage imageWithCGImage:cgImage];
    
    // 顯示處理后的圖片
    UIImageView *imgView = [[UIImageView alloc] init];
    imgView.frame = CGRectMake(40, 40, 200, 200);
    imgView.image = outputUIImage ;
    [self.view addSubview:imgView];

獲取可用的濾鏡列表

  // 所有可用的濾鏡
    NSLog(@"可用的濾鏡\n%@",[CIFilter filterNamesInCategory:kCICategoryBuiltIn])

獲取濾鏡的屬性

    // 濾鏡的屬性
    NSLog(@"%@",blurFilter.attributes)

// 輸出結(jié)果為：

{
    "CIAttributeFilterAvailable_Mac" = "10.4";
    "CIAttributeFilterAvailable_iOS" = 6;
    CIAttributeFilterCategories =     (
        CICategoryBlur,
        CICategoryStillImage,
        CICategoryVideo,
        CICategoryBuiltIn
    );
    CIAttributeFilterDisplayName = "Gaussian Blur";
    CIAttributeFilterName = CIGaussianBlur;
    CIAttributeReferenceDocumentation = "http://developer.apple.com/cgi-bin/apple_ref.cgi?apple_ref=//apple_ref/doc/filter/ci/CIGaussianBlur";
    inputImage =     {
        CIAttributeClass = CIImage;
        CIAttributeDescription = "The image to use as an input image. For filters that also use a background image, this is the foreground image.";
        CIAttributeDisplayName = Image;
        CIAttributeType = CIAttributeTypeImage;
    };
    inputRadius =     {
        CIAttributeClass = NSNumber;
        CIAttributeDefault = 10;
        CIAttributeDescription = "The radius determines how many pixels are used to create the blur. The larger the radius, the blurrier the result.";
        CIAttributeDisplayName = Radius;
        CIAttributeIdentity = 0;
        CIAttributeMin = 0;
        CIAttributeSliderMax = 100;
        CIAttributeSliderMin = 0;
        CIAttributeType = CIAttributeTypeScalar;
    };
}

inputXX即該濾鏡的輸入?yún)?shù)蜓洪。(當(dāng)前濾鏡中即inputRadius)

這樣，通過查詢?yōu)V鏡的attributes的inputXX數(shù)組我們可以得到濾鏡的輸入?yún)?shù)來設(shè)置濾鏡的顯示效果

詳細(xì)解釋輸入?yún)?shù)數(shù)組

• CIAttributeClass -- 該屬性接收的類型

• CIAttributeDefault -- 該屬性的默認(rèn)值

• CIAttributeDescription -- 該屬性的描述

• CIAttributeDisplayName -- 該屬性的名稱

• CIAttributeIdentity -- 屬性標(biāo)識

• CIAttributeMin -- 屬性最小值

• CIAttributeSliderMax -- 屬性最大值

• CIAttributeType -- 屬性類型