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:
1//导入CIImage 2CIImage *ciImage = [[CIImage alloc] initWithImage:[UIImage imageNamed:@"hua"]]; 3 4//创建出Filter滤镜 5CIFilter *filter = [CIFilter filterWithName:@"CIPixellate"]; 6 7[filter setValue:ciImage forKey:kCIInputImageKey]; 8 9[filter setDefaults]; 10 11CIImage *outImage = [filter valueForKey:kCIOutputImageKey]; 12 13//用CIContext将滤镜中的图片渲染出来 14CIContext *context = [CIContext contextWithOptions:nil]; 15 16CGImageRef cgImage = [context createCGImage:outImage 17fromRect:[outImage extent]]; 18 19//导出图片 20UIImage *showImage = [UIImage imageWithCGImage:cgImage]; 21 22CGImageRelease(cgImage); 23 24UIImageView *imageView = [[UIImageView alloc] initWithImage:showImage]; 25imageView.center= self.view.center; 26[self.view addSubview:imageView];
滤镜有哪些可选可以参看以下文章:http://www.jianshu.com/p/3e2cca585ccc
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:
1 //导入CIImage 2CIImage *ciImage = [[CIImage alloc] initWithImage:[UIImage imageNamed:@"hua.jpeg"]]; 3 4//创建出Filter滤镜 5CIFilter *filter = [CIFilter filterWithName:@"CIPixellate"]; 6 7[filter setValue:ciImage forKey:kCIInputImageKey]; 8 9[filter setDefaults]; 10 11CIImage *outImage = [filter valueForKey:kCIOutputImageKey]; 12 13CIFilter *filterTwo = [CIFilter filterWithName:@"CIHueAdjust"]; 14 15[filterTwo setValue:outImage forKey:kCIInputImageKey]; 16 17[filterTwo setDefaults]; 18 19[filterTwo setValue:@(1.0f) forKey:kCIInputAngleKey]; //如果不增加这行新增的滤镜不会生效 20 21CIImage *outputImage = [filterTwo valueForKey:kCIOutputImageKey]; 22 23//用CIContext将滤镜中的图片渲染出来 24CIContext *context = [CIContext contextWithOptions:nil]; 25 26CGImageRef cgImage = [context createCGImage:outputImage 27fromRect:[outputImage extent]]; 28 29//导出图片 30UIImage *showImage = [UIImage imageWithCGImage:cgImage]; 31 32CGImageRelease(cgImage); 33 34UIImageView *imageView = [[UIImageView alloc] initWithImage:showImage]; 35imageView.center= self.view.center; 36[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:
1 //导入要渲染的图片 2UIImage *showImage = [UIImage imageNamed:@"hua.jpeg"]; 3CGRect rect= CGRectMake(0, 0, showImage.size.width, showImage.size.height); 4 5//获取OpenGLES渲染的上下文 6EAGLContext *eagContext = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2]; 7 8//创建出渲染的buffer 9GLKView *glkView = [[GLKView alloc] initWithFrame:rect 10context:eagContext]; 11[glkView bindDrawable]; 12[self.view addSubview:glkView]; 13 14//创建出CoreImage的上下文 15CIContext *ciContext = [CIContext contextWithEAGLContext:eagContext 16options:@{kCIContextWorkingColorSpace: [NSNull null]}]; 17 18//CoreImage相关设置 19CIImage *ciImage = [[CIImage alloc] initWithImage:showImage]; 20 21CIFilter *filter = [CIFilter filterWithName:@"CISepiaTone"]; 22 23[filter setValue:ciImage forKey:kCIInputImageKey]; 24[filter setValue:@(0) forKey:kCIInputIntensityKey]; 25 26//开始渲染 27[ciContext drawImage:[filter valueForKey:kCIOutputImageKey] 28inRect:CGRectMake(0, 0, glkView.drawableWidth, glkView.drawableHeight) 29fromRect:[ciImage extent]]; 30 31[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];
【iOS给图片添加滤镜&使用openGLES动态渲染图片】转载于:https://www.cnblogs.com/zhouxihi/p/6011725.html
