遇到一例案例,iOS 10.1.1 使用CIBlendWithAlphaMask
渲染生成马赛克涂抹效果时,没有渲染出来,改为GPU绘制后,倒就正常了。原因未知,暂且记录下解决方案。
已知问题机型:
iphone 7p iOS 10.1.1
iphone 6sp iOS 10.1.1
iphone 6 iOS 10.1.1
(iphone 5 iOS 10.1.1 没有问题)
原实现:
CIImage *resultImage = [[CIFilter filterWithName:@"CIBlendWithAlphaMask" keysAndValues:kCIInputImageKey, ciOutputImagePixellate, kCIInputMaskImageKey, maskImage, kCIInputBackgroundImageKey, ciInputImage, nil] valueForKey:kCIOutputImageKey];
CIContext *ciContext = [CIContext contextWithOptions:nil]; CGImageRef cgImage = [ciContext createCGImage:resultImage fromRect:[resultImage extent]];
CGImageRef cgImage = [ciContext createCGImage:resultImage fromRect:[resultImage extent]];
UIImage *filteredImage = [UIImage imageWithCGImage:cgImage]; CGImageRelease(cgImage);
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修改后实现方案:
CIImage *resultImage = [[CIFilter filterWithName:@"CIBlendWithAlphaMask" keysAndValues:kCIInputImageKey, ciOutputImagePixellate, kCIInputMaskImageKey, maskImage, kCIInputBackgroundImageKey, ciInputImage, nil] valueForKey:kCIOutputImageKey]; EAGLContext *glContext = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];
CIContext *ciContext = [CIContext contextWithEAGLContext:glContext options:@{kCIContextWorkingColorSpace : [NSNull null]}]; CGImageRef cgImage = [ciContext createCGImage:resultImage fromRect:[resultImage extent]];
UIImage *filteredImage = [UIImage imageWithCGImage:cgImage]; CGImageRelease(cgImage);
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附上图片部分马赛克的源码:
- (UIImage *)demoCoreImageFilter { UIImage *originImage = [UIImage imageNamed:@"facetest"]; CIImage *ciInputImage = [[CIImage alloc] initWithImage:originImage]; CIFilter *filterPixellate = [CIFilter filterWithName:@"CIPixellate"]; [filterPixellate setValue:ciInputImage forKey:kCIInputImageKey]; [filterPixellate setDefaults]; [filterPixellate setValue:@32 forKey:@"inputScale"]; NSLog(@"filterPixellate : %@", filterPixellate.attributes); CIImage *ciOutputImagePixellate = [filterPixellate valueForKey:kCIOutputImageKey]; CIDetector *detector = [CIDetector detectorOfType:CIDetectorTypeFace context:nil options:nil]; NSArray *faceArray = [detector featuresInImage:ciInputImage options:nil]; CIImage *maskImage = nil; for (CIFeature *f in faceArray) { CGFloat centerX = f.bounds.origin.x + f.bounds.size.width / 2.0; CGFloat centerY = f.bounds.origin.y + f.bounds.size.height / 2.0; CGFloat radius = MIN(f.bounds.size.width, f.bounds.size.height) / 1.5; CIFilter *radialGradient = [CIFilter filterWithName:@"CIRadialGradient" withInputParameters:@{ @"inputRadius0": @(radius), @"inputRadius1": @(radius + 1.0f), @"inputColor0": [CIColor colorWithRed:0.0 green:1.0 blue:0.0 alpha:1.0], @"inputColor1": [CIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:0.0], kCIInputCenterKey: [CIVector vectorWithX:centerX Y:centerY], }]; CIImage *circleImage = [radialGradient valueForKey:kCIOutputImageKey]; if (nil == maskImage) maskImage = circleImage; else maskImage = [[CIFilter filterWithName:@"CISourceOverCompositing" withInputParameters:@{ kCIInputImageKey: circleImage, kCIInputBackgroundImageKey: maskImage, }] valueForKey:kCIOutputImageKey]; } CIImage *resultImage = [[CIFilter filterWithName:@"CIBlendWithAlphaMask" keysAndValues:kCIInputImageKey, ciOutputImagePixellate, kCIInputMaskImageKey, maskImage, kCIInputBackgroundImageKey, ciInputImage, nil] valueForKey:kCIOutputImageKey]; EAGLContext *glContext = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2]; CIContext *ciContext = [CIContext contextWithEAGLContext:glContext options:@{kCIContextWorkingColorSpace : [NSNull null]}]; CGImageRef cgImage = [ciContext createCGImage:resultImage fromRect:[resultImage extent]]; UIImage *filteredImage = [UIImage imageWithCGImage:cgImage]; CGImageRelease(cgImage); return filteredImage; }
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代码讲解:
- 将原图马赛克化,得到一张马赛克后的图片 ciOutputImagePixellate
- 对原图人脸识别,并取识别后的人脸区域 maskImage
- 使用 CIBlendWithAlphaMask 滤镜进行合成
- 指定GPU 渲染
参考链接
Anonymous Faces Filter Recipe