iOS给图片添加滤镜&使用openGLES动态渲染图片详解及实例

iOS给图片添加滤镜&使用openGLES动态渲染图片

给图片增加滤镜有这两种方式: CoreImage / openGLES

下面先说明如何使用CoreImage给图片添加滤镜, 主要为以下步骤:

#1.导入CIImage格式的原始图片

#2.创建CIFilter滤镜

#3.用CIContext将滤镜中的图片渲染出来

#4.导出渲染后的图片

参考代码:

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//导入CIImage

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

//创建出Filter滤镜

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

[filter setValue:ciImage forKey:kCIInputImageKey];

[filter setDefaults];

CIImage *outImage = [filter valueForKey:kCIOutputImageKey];

//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]];

//导出图片

UIImage *showImage = [UIImage imageWithCGImage:cgImage];

CGImageRelease(cgImage);

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

imageView.center = self.view.center;

[self.view addSubview:imageView];

当要设置多个滤镜的时候, 出了新创建一个CIFilter外还要额外设定kCIInputAngleKey, 代码如下:

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//导入CIImage

CIImage *ciImage = [[CIImage alloc] initWithImage:[UIImage imageNamed:@"hua.jpeg"]];

//创建出Filter滤镜

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

[filter setValue:ciImage forKey:kCIInputImageKey];

[filter setDefaults];

CIImage *outImage = [filter valueForKey:kCIOutputImageKey];

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

[filterTwo setValue:outImage forKey:kCIInputImageKey];

[filterTwo setDefaults];

[filterTwo setValue:@(1.0f) forKey:kCIInputAngleKey]; //如果不增加这行新增的滤镜不会生效

CIImage *outputImage = [filterTwo valueForKey:kCIOutputImageKey];

//用CIContext将滤镜中的图片渲染出来

CIContext *context = [CIContext contextWithOptions:nil];

CGImageRef cgImage = [context createCGImage:outputImage

fromRect:[outputImage extent]];

//导出图片

UIImage *showImage = [UIImage imageWithCGImage:cgImage];

CGImageRelease(cgImage);

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

imageView.center = self.view.center;

[self.view addSubview:imageView];

下面来介绍怎么用openGLES来使用滤镜渲染图片

使用openGlES的步骤大致如下:

#1.导入要渲染的图片

#2.获取OpenGLES渲染的上下文

#3.创建出渲染的GLKView buffer

#4.创建CoreImage的上下文

#5.进行CoreImage的相关设置

#6.开始渲染并显示图片

参考代码如下:

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//导入要渲染的图片

UIImage *showImage = [UIImage imageNamed:@"hua.jpeg"];

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 = [[GLKView alloc] initWithFrame:rect

context:eagContext];

[glkView bindDrawable];

[self.view addSubview:glkView];

//创建出CoreImage的上下文

CIContext *ciContext = [CIContext contextWithEAGLContext:eagContext

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

//CoreImage相关设置

CIImage *ciImage = [[CIImage alloc] initWithImage:showImage];

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

[filter setValue:ciImage forKey:kCIInputImageKey];

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

//开始渲染

[ciContext drawImage:[filter valueForKey:kCIOutputImageKey]

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

fromRect:[ciImage extent]];

[glkView display];

如果要动态渲染, 可以通过UISilder动态调整一下代码的vaule值

[filter setValue:vaule forKey:kCIInputIntensityKey];

感谢阅读,希望能帮助到大家,谢谢大家对本站的支持!

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