ios - CIDetector : CIFaceFeature with always zero bounds

Question

我不知道为什么我得到的 CIFaceFeature 总是返回零矩形:

import Cocoa
import QuartzCore

let url = NSURL(string:"http://cs620522.vk.me/v620522149/12b59/ijvZ6XJWrw0.jpg");
let ciimg:CIImage = CIImage(contentsOfURL:url);
let cid:CIDetector = CIDetector(ofType:CIDetectorTypeFace, context:nil, options:[CIDetectorAccuracy: CIDetectorAccuracyHigh]);
let results:NSArray = cid.featuresInImage(ciimg, options: NSDictionary());
for r in results {
    let face:CIFaceFeature = r as CIFaceFeature;
    NSLog("Face found at (%f,%f) of dimensions %fx%f", face.bounds.origin.x, face.bounds.origin.y, face.bounds.width, face.bounds.height);
}

根据 NSLog 的数量，CIDetector.featuresInImage 似乎有效。

Answer 1

您应该使用println 来记录信息。或者您可以使用以下内容，

NSLog("%@ face", face.bounds.origin.x.description)