图片虚化处理

最近在某些app 上面看到banner 图的图片虚化，然后花了一点时间去处理了这个问题

#import "ViewController.h"

@interface ViewController ()

@property(nonatomic,strong)UIImageView *imageView;

@property(nonatomic,strong)UIImageView *imgView;

@end

@implementation ViewController

//懒加载

- (UIImageView *)imageView

{

if (_imageView == nil) {

_imageView = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 200, 200)];

_imageView.backgroundColor = [UIColor orangeColor];

}

return _imageView;

}

- (UIImageView *)imgView

{

if (_imgView == nil) {

_imgView = [[UIImageView alloc]initWithFrame:CGRectMake(0, 300, 200, 200)];

_imgView.backgroundColor = [UIColor orangeColor];

}

return _imgView;

}

- (void)viewDidLoad {

[super viewDidLoad];

[self dealImgView1];

[self text];

}

- (void)dealImgView1 {

// coreImage是IOS5中新加入的一个Objective-c的框架，提供了强大高效的图像处理功能，用来对基于像素的图像进行操作与分析。iOS提供了很多强大的滤镜(Filter)，现在有127种之多,随着框架的更新，这一数字会继续增加。这些Filter提供了各种各样的效果，并且还可以通过滤镜链将各种效果的Filter叠加起来，形成强大的自定义效果，如果你对该效果很满意，还可以子类化滤镜。下面将代码贴在下面,与大家分享,如果对框架不熟悉,建议阅读苹果的官方API.

[self.view addSubview:self.imgView];

CIImage *inputImage = [[CIImage alloc] initWithImage:[UIImage imageNamed:@"图片的名字"]];

//CIFilter,高斯模糊滤镜

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

//将图片输入到滤镜中

[filter setValue:inputImage forKey:kCIInputImageKey];

//设置模糊程度,默认为10,取值范围(0-100)

[filter setValue:[NSNumber numberWithFloat:10.0] forKey:@"inputRadius"];

//将处理好的图片输出

CIImage *result = [filter valueForKey:kCIOutputImageKey];

//CIImage *result=[filter outputImage];//两种方法都可以

CIContext *context = [CIContext contextWithOptions:nil];

//获取CGImage句柄,也就是从数据流中取出图片

CGImageRef cgImage = [context createCGImage:result fromRect:[inputImage extent]];

#warning result inputImage 变化不同（）

// CGImageRef cgImage = [context createCGImage:result fromRect:[result extent]];

//最终获取到图片

UIImage *image = [UIImage imageWithCGImage:cgImage];

//释放CGImage句柄

CGImageRelease(cgImage);

self.imgView.image=image;

}

下面是虚化的样子

为什么会出现两个呢而且不同的虚化模式

关键是：有一句代码不一样

//获取CGImage句柄,也就是从数据流中取出图片

CGImageRef cgImage = [context createCGImage:result fromRect:[inputImage extent]];

#warning result inputImage 变化不同（）

// CGImageRef cgImage = [context createCGImage:result fromRect:[result extent]];

[inputImage extent ] 一个是处理前的图片一个是处理后的图片

[result extent]

附录：

//用来查询滤镜可以设置的参数以及一些相关的信息

NSLog(@"%@",[filter attributes]);

[blurFilter attributes]打印结果如下:

//参数以及一些相关的信息,如果不做任何的设置,默认程度为10( CIAttributeDefault = 10);

2016-08-01 17:02:44.552 钱钱钱钱钱[6935:207227] {

"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;

};

}

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