我正在尝试编写一个带有UI
Image的例程,并返回一个只包含face的新UIImage.这看起来非常简单,但我的大脑在绕过CoreImage和UIImage空间时遇到了问题.
这是基础知识：
- (UIImage *)imageFromImage:(UIImage *)image inRect:(CGRect)rect {
CGImageRef sourceImageRef = [image CGImage];
CGImageRef newImageRef = CGImageCreateWithImageInRect(sourceImageRef,rect);
UIImage *newImage = [UIImage imageWithCGImage:newImageRef];
CGImageRelease(newImageRef);
return newImage;
}
-(UIImage *)getFaceImage:(UIImage *)picture {
CIDetector *detector = [CIDetector detectorOfType:CIDetectorTypeFace
context:nil
options:[NSDictionary dictionaryWithObject: CIDetectorAccuracyHigh forKey: CIDetectorAccuracy]];
CIImage *ciImage = [CIImage imageWithCGImage: [picture CGImage]];
NSArray *features = [detector featuresInImage:ciImage];
// For simplicity,I'm grabbing the first one in this code sample,// and we can all pretend that the photo has one face for sure. :-)
CIFaceFeature *faceFeature = [features objectAtIndex:0];
return imageFromImage:picture inRect:faceFeature.bounds;
}
返回的图像来自翻转图像.我尝试使用以下方法调整faceFeature.bounds：
CGAffineTransform t = CGAffineTransformMakeScale(1.0f,-1.0f); CGRect newRect = CGRectApplyAffineTransform(faceFeature.bounds,t);
…但是这给了我图像之外的结果.
我确定有一些简单的方法可以解决这个问题,但是如果没有计算自下而上,然后使用它作为X创建一个新的rect,是否有“正确”的方法来做到这一点？
谢谢！
解决方法
使用CIContext从图像中裁剪脸部会更容易,也不那么麻烦.像这样的东西：
CGImageRef cgImage = [_ciContext createCGImage:[CIImage imageWithCGImage:inputImage.CGImage] fromRect:faceFeature.bounds]; UIImage *croppedFace = [UIImage imageWithCGImage:cgImage];
其中inputImage是您的UIImage对象,faceFeature对象是您从[CIDetector featuresInImage：]方法获得的CIFaceFeature类型.
