CoreImage 处置图片

CoreImage 处理图片

1.CoreImage 滤镜的使用(马赛克模糊)

随着iOS版本升级以及硬件性能的不断提升，CoreImage将支持越来越多的滤镜

- (void)hFilter {

    // 0. 导入CIImage图片

    CIImage *ciImage = [[CIImage alloc] initWithImage:[UIImage imageNamed:@"demo"]];

    

    // 1. 创建出Filter滤镜

    CIFilter *filter = [CIFilter filterWithName:@"CIPixellate"];

    

    [filter setValue:ciImage

              forKey:kCIInputImageKey];

    

    NSLog(@"%@", filter.attributes);

    

    [filter setDefaults];

    

    CIImage *outImage = [filter valueForKey:kCIOutputImageKey];

    

    // 2. 用CIContext将滤镜中的图片渲染出来

    CIContext *context = [CIContext contextWithOptions:nil];

    

    CGImageRef cgImage = [context createCGImage:outImage

                                       fromRect:[outImage extent]];

    

    // 3. 导出图片

    UIImage *showImage = [UIImage imageWithCGImage:cgImage];

    

    CGImageRelease(cgImage);

    

    // 4. 加载出来

    UIImageView *imageView = [[UIImageView alloc] initWithImage:showImage];

    imageView.center       = self.view.center;

    [self.view addSubview:imageView];

}

2.CoreImage 滤镜的组合

可以动态的修改滤镜组合中单个滤镜的参数来实现一种动态调整的效果

- (void)complexCoreImage {

    // 0. 导入CIImage图片

    CIImage *ciImage = [[CIImage alloc] initWithImage:[UIImage imageNamed:@"demo"]];

    

    // 1. 创建出Filter滤镜

    CIFilter *filterOne = [CIFilter filterWithName:@"CIPixellate"];

    

    [filterOne setValue:ciImage

              forKey:kCIInputImageKey];

    

    [filterOne setDefaults];

    

    CIImage *outImage = [filterOne valueForKey:kCIOutputImageKey];

    

    CIFilter *filterTwo = [CIFilter filterWithName:@"CIHueAdjust"];

    [filterTwo setValue:outImage

                 forKey:kCIInputImageKey];

    

    [filterTwo setDefaults];

    //默认为0,不设置不能改变，可以封装一个调用

    [filterTwo setValue:@(3.14)

                 forKey:kCIInputAngleKey];

    NSLog(@"%@",filterTwo.attributes);//可以看到一些参数 key

    

    CIImage *outputImage = [filterTwo valueForKey:kCIOutputImageKey];

    

    // 2. 用CIContext将滤镜中的图片渲染出来

    CIContext *context = [CIContext contextWithOptions:nil];

    

    CGImageRef cgImage = [context createCGImage:outputImage

                                       fromRect:[outImage extent]];

    

    // 3. 导出图片

    UIImage *showImage = [UIImage imageWithCGImage:cgImage];

    

    CGImageRelease(cgImage);

    

    // 4. 加载出来

    UIImageView *imageView = [[UIImageView alloc] initWithImage:showImage];

    imageView.center       = self.view.center;

    [self.view addSubview:imageView];

}

3.在 OpenGLES 下进行渲染

如果需要实时查看多个滤镜动态渲染的效果，使用OpenGLES是一个好的选择

#import <GLKit/GLKit.h>

@interface ViewController ()

@property (nonatomic, strong) GLKView   *glkView; // 渲染用的buffer视图

@property (nonatomic, strong) CIFilter  *filter;

@property (nonatomic, strong) CIImage   *ciImage;

@property (nonatomic, strong) CIContext *ciContext;

@end

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    UIImage *showImage = [UIImage imageNamed:@"demo"];

    CGRect  rect       = CGRectMake(0, 0, showImage.size.width, showImage.size.height);

    

    // 获取OpenGLES渲染的上下文

    EAGLContext *eagContext = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];

    

    // 创建出渲染的buffer

    _glkView = [[GLKView alloc] initWithFrame:rect

                                      context:eagContext];

    [_glkView bindDrawable];

    [self.view addSubview:_glkView];

    

    // 创建出CoreImage用的上下文

    _ciContext = [CIContext contextWithEAGLContext:eagContext

                                           options:@{kCIContextWorkingColorSpace : [NSNull null]}];

    

    // CoreImage相关设置

    _ciImage = [[CIImage alloc] initWithImage:showImage];

    

    _filter = [CIFilter filterWithName:@"CISepiaTone"];

    

    [_filter setValue:_ciImage forKey:kCIInputImageKey];

    [_filter setValue:@(0) forKey:kCIInputIntensityKey];

    

    // 开始渲染

    [_ciContext drawImage:[_filter outputImage]

                   inRect:CGRectMake(0, 0, _glkView.drawableWidth, _glkView.drawableHeight)

                 fromRect:[_ciImage extent]];

    [_glkView display];

    

    // 动态渲染

    UISlider *slider    = [[UISlider alloc] initWithFrame:CGRectMake(0, 400, 320, 20)];

    slider.minimumValue = 0.f;

    slider.maximumValue = 1.f;

    [slider addTarget:self action:@selector(sliderEvent:) forControlEvents:UIControlEventValueChanged];

    [self.view addSubview:slider];

}

- (void)sliderEvent:(UISlider *)slider {

    [_filter setValue:_ciImage forKey:kCIInputImageKey];

    [_filter setValue:@(slider.value)

               forKey:kCIInputIntensityKey];

    

    // 开始渲染

    [_ciContext drawImage:[_filter outputImage]

                   inRect:CGRectMake(0, 0, _glkView.drawableWidth, _glkView.drawableHeight)

                 fromRect:[_ciImage extent]];

    [_glkView display];

}