改变图片的饱和度、亮度、对比度

最新推荐文章于 2022-04-20 17:22:12 发布

原创最新推荐文章于 2022-04-20 17:22:12 发布 · 1.6k 阅读

CC 4.0 BY-SA版权

该博客介绍了如何在iOS应用中使用Core Image框架来改变图片的饱和度、亮度和对比度。通过创建CIImage对象，设置CIColorControls滤镜的参数，然后利用CIContext创建最终的CGImage，实现图片效果的调整。此外，还展示了获取和设置屏幕亮度的方法，并列出所有可用的CIFilter以供参考。

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- (void)viewDidLoad {
    [super viewDidLoad];

    UIImage *image = [UIImage imageNamed:@"默认@2x"];
    CIImage *beginImage = [CIImage imageWithCGImage:image.CGImage];
    CIFilter *filter = [CIFilter filterWithName:@"CIColorControls"];
    [filter setValue:beginImage forKey:kCIInputImageKey];
    //饱和度 0 -- 2
    [filter setValue:[NSNumber numberWithFloat:0.5] forKey:@"inputSaturation"];
    //亮度   -1 --- 1
    [filter setValue:[NSNumber numberWithFloat:0.5] forKey:@"inputBrightness"];
    //对比度 0 --- 4
    [filter setValue:[NSNumber numberWithFloat:2] forKey:@"inputContrast"];

    //得到过滤后的图片

    CIImage *outputImage = [filter outputImage];
    //转换图片，创建基于GPU的CIContext对象
    CIContext *context = [CIContext contextWithOptions:nil];
    CGImageRef cgimg = [context createCGImage:outputImage fromRect:[outputImage extent]];
    UIImage *newImg = [UIImage imageWithCGImage:cgimg];
//    float value = [UIScreen mainScreen].brightness;
////    NSLog(@"获取手机屏幕亮度%f",value);
//    [[UIScreen mainScreen] setBrightness:0.7];
//    NSLog(@"获取手机屏幕亮度%f",value);


    UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 20, self.view.frame.size.width, 170)];
    [self.view addSubview:imageView];
    imageView.image = newImg;


}
- (void) imageBrighter{

    NSArray *cifilter = [CIFilter filterNamesInCategory:kCICategoryBuiltIn];

    NSLog(@"FilterName:\n%@,,,===%ld", cifilter,cifilter.count);//显示所有过滤器名字

    for (NSString *filterName in cifilter) {

        CIFilter *fltr = [CIFilter filterWithName:filterName];//用一个过滤器名字生成一个过滤器CIFilter对象

        NSLog(@"%@:\n%@", filterName, [fltr attributes]);//这个过滤器支持的属性

    }

}