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]];
// 获取UIImage
UIImage *filteredImage = [UIImage imageWithCGImage:cgImage];
CGImageRelease(cgImage);
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]];
// 获取UIImage
UIImage *filteredImage = [UIImage imageWithCGImage:cgImage];
CGImageRelease(cgImage);
附上图片部分马赛克的源码:
- (UIImage *)demoCoreImageFilter {
UIImage *originImage = [UIImage imageNamed:@"facetest"];
// 导入CIImage
CIImage *ciInputImage = [[CIImage alloc] initWithImage:originImage];
// 创建CIFilter
CIFilter *filterPixellate = [CIFilter filterWithName:@"CIPixellate"];
[filterPixellate setValue:ciInputImage forKey:kCIInputImageKey];
[filterPixellate setDefaults];
[filterPixellate setValue:@32 forKey:@"inputScale"];
NSLog(@"filterPixellate : %@", filterPixellate.attributes);
// 获取滤镜效果之后的CIImage
CIImage *ciOutputImagePixellate = [filterPixellate valueForKey:kCIOutputImageKey];
// 人脸识别
CIDetector *detector = [CIDetector detectorOfType:CIDetectorTypeFace
context:nil
options:nil];
NSArray *faceArray = [detector featuresInImage:ciInputImage options:nil];
// Create a green circle to cover the rects that are returned.
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]];
// 获取UIImage
UIImage *filteredImage = [UIImage imageWithCGImage:cgImage];
CGImageRelease(cgImage);
return filteredImage;
}
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