iOS 滤镜效果

Simulator Screen Shot 2016年8月18日 下午2.00.24.png Simulator Screen Shot 2016年8月18日 下午2.01.28.png

#import "ViewController.h"
@interface ViewController (){
    UIImageView *imageView;
    NSArray *array;
    NSOperationQueue *queue;// 多线程（操作队列)中去执行，而且是异步执行的。）
}  

@end

@implementation ViewController

- (void)viewDidLoad {
[super viewDidLoad];
/*
 需求1:屏幕上边显示着一张图片,在下方有一个scalorView可以滑动
 里面填充的是已经渲染好的图片
 2.通过菊花器来加载图片,在子线程中加载
 3.图片的渲染是带有动画效果
 4.子线程改变图片的coreImage不要卡UI
 ps:使用线程的时候不要使用全局变量,在for循环里面,否则只有最后一个能附上值
 
 */
    int viewWidth=[[UIScreen mainScreen]bounds].size.width;
    int viewHeight=[[UIScreen mainScreen]bounds].size.height;

    queue=[[NSOperationQueue alloc]init];//创建操作队列

    array=@[@"CIPhotoEffectMono",@"CIPhotoEffectTonal",@"CIPhotoEffectNoir",@"CIPhotoEffectFade",@"CIPhotoEffectChrome",@"CIPhotoEffectProcess",@"CIPhotoEffectTransfer",@"CIPhotoEffectInstant",@"CISRGBToneCurveToLinear"];

    CGRect imageViewRect=CGRectMake(0, 0, viewWidth, viewHeight-150);

    imageView=[[UIImageView alloc]initWithFrame:imageViewRect];
    imageView.image=[UIImage imageNamed:@"4.jpg"];
    imageView.contentMode=UIViewContentModeScaleAspectFit;//图片自适应
    [self.view addSubview:imageView];

    CGRect scrollViewRect=CGRectMake(0, viewHeight-150, viewWidth, 150);
    UIScrollView *scrollView=[[UIScrollView alloc]initWithFrame:scrollViewRect];
    scrollView.backgroundColor=[UIColor orangeColor];
    scrollView.contentSize=CGSizeMake(110*9-10, 130);

    for (int i=0; i<9; i++) {
        //photo
        CGRect imageViewRect=CGRectMake((100 +10)*i, 10, 100, 130);
        UIImageView *imageViewScroll=[[UIImageView alloc]initWithFrame:imageViewRect];
        imageViewScroll.contentMode=UIViewContentModeScaleAspectFit;
        [scrollView addSubview:imageViewScroll];
        //活动指示器
        UIActivityIndicatorView *indicatorView=[[UIActivityIndicatorView alloc]initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite];
        
        indicatorView.center=CGPointMake(imageViewScroll.frame.size.width/2, imageViewScroll.frame.size.height/2);

        [indicatorView startAnimating];

        [imageViewScroll addSubview:indicatorView];

        //tag各单击事件
        UITapGestureRecognizer *tap= [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(tapAction:)];
        imageViewScroll.tag=i;
        [imageViewScroll addGestureRecognizer:tap];
        imageViewScroll.userInteractionEnabled=YES;
        //多线程
        NSBlockOperation *photo_block=[NSBlockOperation blockOperationWithBlock:^{
        //加载图片
        UIImage *image=[self filterImage:array[i] originImage:[UIImage imageNamed:@"4.jpg"]];
        [imageViewScroll performSelectorOnMainThread:@selector(setImage:) withObject:image waitUntilDone:NO];
        //停止菊花器
        NSBlockOperation *stopIndicator=[NSBlockOperation blockOperationWithBlock:^{
            [self performSelectorOnMainThread:@selector(updateIndicator:) withObject:indicatorView waitUntilDone:YES];
            }];
            [queue addOperation:stopIndicator];
        }];
        [queue addOperation:photo_block];
    }
    [self.view addSubview:scrollView];
}
-(void)tapAction:(UITapGestureRecognizer *)sender{
    UIImageView *imageV=(UIImageView *)sender.view;
    imageView.image=imageV.image;
}
//filter
-(UIImage *)filterImage:(NSString *)type originImage:(UIImage *)image{
    CIContext *context=[CIContext contextWithOptions:nil];
    CIImage *resultImage=[[CIImage alloc]initWithCGImage:image.CGImage];
    //系统滤镜
    CIFilter *filter=[CIFilter filterWithName:type];
    //传入要过滤的图片
    [filter setValue:resultImage forKey:kCIInputImageKey];
    //输出过滤后图片
    resultImage =filter.outputImage;
    CGRect extent=[resultImage extent];
    CGImageRef cgImage=[contextcreateCGImage:resultImage fromRect:extent];
    UIImage *result=[UIImage imageWithCGImage:cgImage];
    return result;
}
//stop 活动指示器
-(void)updateIndicator:(UIActivityIndicatorView *)sender{
    [sender stopAnimating];
    [sender removeFromSuperview];
}
@end