iOS給圖片添加濾鏡&使用openGLES動(dòng)態(tài)渲染圖片
給圖片增加濾鏡有這兩種方式: CoreImage / openGLES
下面先說(shuō)明如何使用CoreImage給圖片添加濾鏡, 主要為以下步驟:
#1.導(dǎo)入CIImage格式的原始圖片
#2.創(chuàng)建CIFilter濾鏡
#3.用CIContext將濾鏡中的圖片渲染出來(lái)
#4.導(dǎo)出渲染后的圖片
參考代碼:
//導(dǎo)入CIImage CIImage *ciImage = [[CIImage alloc] initWithImage:[UIImage imageNamed:@"hua"]]; //創(chuàng)建出Filter濾鏡 CIFilter *filter = [CIFilter filterWithName:@"CIPixellate"]; [filter setValue:ciImage forKey:kCIInputImageKey]; [filter setDefaults]; CIImage *outImage = [filter valueForKey:kCIOutputImageKey]; //用CIContext將濾鏡中的圖片渲染出來(lái) CIContext *context = [CIContext contextWithOptions:nil]; CGImageRef cgImage = [context createCGImage:outImage fromRect:[outImage extent]]; //導(dǎo)出圖片 UIImage *showImage = [UIImage imageWithCGImage:cgImage]; CGImageRelease(cgImage); UIImageView *imageView = [[UIImageView alloc] initWithImage:showImage]; imageView.center = self.view.center; [self.view addSubview:imageView];
當(dāng)要設(shè)置多個(gè)濾鏡的時(shí)候, 出了新創(chuàng)建一個(gè)CIFilter外還要額外設(shè)定kCIInputAngleKey, 代碼如下:
//導(dǎo)入CIImage CIImage *ciImage = [[CIImage alloc] initWithImage:[UIImage imageNamed:@"hua.jpeg"]]; //創(chuàng)建出Filter濾鏡 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]; //如果不增加這行新增的濾鏡不會(huì)生效 CIImage *outputImage = [filterTwo valueForKey:kCIOutputImageKey]; //用CIContext將濾鏡中的圖片渲染出來(lái) CIContext *context = [CIContext contextWithOptions:nil]; CGImageRef cgImage = [context createCGImage:outputImage fromRect:[outputImage extent]]; //導(dǎo)出圖片 UIImage *showImage = [UIImage imageWithCGImage:cgImage]; CGImageRelease(cgImage); UIImageView *imageView = [[UIImageView alloc] initWithImage:showImage]; imageView.center = self.view.center; [self.view addSubview:imageView];
下面來(lái)介紹怎么用openGLES來(lái)使用濾鏡渲染圖片
使用openGlES的步驟大致如下:
#1.導(dǎo)入要渲染的圖片
#2.獲取OpenGLES渲染的上下文
#3.創(chuàng)建出渲染的GLKView buffer
#4.創(chuàng)建CoreImage的上下文
#5.進(jìn)行CoreImage的相關(guān)設(shè)置
#6.開(kāi)始渲染并顯示圖片
參考代碼如下:
//導(dǎo)入要渲染的圖片 UIImage *showImage = [UIImage imageNamed:@"hua.jpeg"]; CGRect rect = CGRectMake(0, 0, showImage.size.width, showImage.size.height); //獲取OpenGLES渲染的上下文 EAGLContext *eagContext = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2]; //創(chuàng)建出渲染的buffer GLKView *glkView = [[GLKView alloc] initWithFrame:rect context:eagContext]; [glkView bindDrawable]; [self.view addSubview:glkView]; //創(chuàng)建出CoreImage的上下文 CIContext *ciContext = [CIContext contextWithEAGLContext:eagContext options:@{kCIContextWorkingColorSpace: [NSNull null]}]; //CoreImage相關(guān)設(shè)置 CIImage *ciImage = [[CIImage alloc] initWithImage:showImage]; CIFilter *filter = [CIFilter filterWithName:@"CISepiaTone"]; [filter setValue:ciImage forKey:kCIInputImageKey]; [filter setValue:@(0) forKey:kCIInputIntensityKey]; //開(kāi)始渲染 [ciContext drawImage:[filter valueForKey:kCIOutputImageKey] inRect:CGRectMake(0, 0, glkView.drawableWidth, glkView.drawableHeight) fromRect:[ciImage extent]]; [glkView display];如果要?jiǎng)討B(tài)渲染, 可以通過(guò)UISilder動(dòng)態(tài)調(diào)整一下代碼的vaule值
[filter setValue:vaule forKey:kCIInputIntensityKey];
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