在iOS7中创建模糊效果 [英] Creating a blur effect in iOS7

问题描述

我几个小时以来一直在寻找这个问题的答案，而我无法理解。当我按下按钮按钮时，我想为图像添加高斯模糊效果。用户是添加图像的用户。

I have been searching for an answer to this question in a few hours now, and I just can't figure it out. I want to add a gaussian blur effect to the image when i press the button "Button". The user is the one that is adding the image.

我已经根据SO和网络上其他地方的来源为按钮创建了一个动作。不起作用。我究竟做错了什么？任何代码将不胜感激。这是我的按钮动作：

I have created an action for the "Button" based on sources from SO and other places on the web. It will not work. What am I doing wrong? Any code would be greatly appreciated. Here is my "Button" action:

- (IBAction)test:(id)sender {
    CIFilter *gaussianBlurFilter = [CIFilter filterWithName: @"CIGaussianBlur"];
    [gaussianBlurFilter setValue:imageView.image forKey: @"inputImage"];
    [gaussianBlurFilter setValue:[NSNumber numberWithFloat: 10] forKey: @"inputRadius"];
}

如果您还需要我做的其他事情来回答这个问题，请让我知道：D

If you need anything else that I have done to answer the question, please let me know :D

推荐答案

三个观察结果：

1. 您需要将 inputImage 设置为 UIImage中的 CIImage ：

1. You need to set the inputImage to be the the CIImage from your UIImage:

[gaussianBlurFilter setValue:[CIImage imageWithCGImage:[imageView.image CGImage]] forKey:kCIInputImageKey];

我没有看到你抓住 outputImage ，例如：

CIImage *outputImage = [gaussianBlurFilter outputImage];

你可能想转换那个 CIImage 返回 UIImage 。

所以，把它们放在一起：

So, putting that all together:

CIFilter *gaussianBlurFilter = [CIFilter filterWithName:@"CIGaussianBlur"];
[gaussianBlurFilter setDefaults];
CIImage *inputImage = [CIImage imageWithCGImage:[imageView.image CGImage]];
[gaussianBlurFilter setValue:inputImage forKey:kCIInputImageKey];
[gaussianBlurFilter setValue:@10 forKey:kCIInputRadiusKey];

CIImage *outputImage = [gaussianBlurFilter outputImage];
CIContext *context   = [CIContext contextWithOptions:nil];
CGImageRef cgimg     = [context createCGImage:outputImage fromRect:[inputImage extent]];  // note, use input image extent if you want it the same size, the output image extent is larger
UIImage *image       = [UIImage imageWithCGImage:cgimg];
CGImageRelease(cgimg);

---

或者，如果你去 WWDC 2013示例代码（需要付费开发者订阅）并下载 iOS_UIImageEffects ，然后你可以获得 UIImage + ImageEffects 类别。这提供了一些新方法：

---

Alternatively, if you go to the WWDC 2013 sample code (paid developer subscription required) and download iOS_UIImageEffects, you can then grab the UIImage+ImageEffects category. That provides a few new methods:

- (UIImage *)applyLightEffect;
- (UIImage *)applyExtraLightEffect;
- (UIImage *)applyDarkEffect;
- (UIImage *)applyTintEffectWithColor:(UIColor *)tintColor;
- (UIImage *)applyBlurWithRadius:(CGFloat)blurRadius tintColor:(UIColor *)tintColor saturationDeltaFactor:(CGFloat)saturationDeltaFactor maskImage:(UIImage *)maskImage;

因此，为了模糊和成像并使其变亮（赋予磨砂玻璃效果），您可以执行：

So, to blur and image and lightening it (giving that "frosted glass" effect) you can then do:

UIImage *newImage = [image applyLightEffect];

有趣的是，Apple的代码不使用 CIFilter ，而是致电 vImageBoxConvolve_ARGB8888 Performance / Conceptual / vImage / Introduction / Introduction.html＃// apple_ref / doc / uid / TP30001001> vImage高性能图像处理框架。

Interestingly, Apple's code does not employ CIFilter, but rather calls vImageBoxConvolve_ARGB8888 of the vImage high-performance image processing framework.

WWDC 2013视频在iOS上实施Engaging UI 中说明了这种技术。

This technique is illustrated in WWDC 2013 video Implementing Engaging UI on iOS.

我知道问题是关于iOS 7，但是现在在iOS 8中可以为任何 UIView添加模糊效果对象 UIBlurEffect ：

I know the question was about iOS 7, but now in iOS 8 one can add a blur effect to any UIView object with UIBlurEffect:

UIVisualEffect *effect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleLight];
UIVisualEffectView *effectView = [[UIVisualEffectView alloc] initWithEffect:effect];    
effectView.frame = imageView.bounds;
[imageView addSubview:effectView];

这篇关于在iOS7中创建模糊效果的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！