我正在使用Swift进行视频处理。在升级到El Capitan(和Swift 2)之后,我的代码出现了问题。我追踪到一个错误,原因是CIFilter函数CIColorClamp。这个函数应该夹住像素值,但实际上会破坏图像范围。
let _c:CGFloat = 0.05
let minComp = CIVector(x:_c, y:_c, z:_c, w: 1)
let maxComp = CIVector(x:1, y:1, z:1, w: 1)
let clamp: CIFilter = CIFilter(name: "CIColorClamp")!
print("clamp-in \(image.extent)")
clamp.setDefaults()
clamp.setValue(image, forKey: kCIInputImageKey)
clamp.setValue(minComp, forKey: "inputMinComponents")
clamp.setValue(maxComp, forKey: "inputMaxComponents")
print("clamp-out \(clamp.outputImage!.extent)")
上面的代码会产生以下输出:
> clamp-in (6.0, 6.0, 1268.0, 708.0)
CoreAnimation: Warning! CAImageQueueSetOwner() is deprecated and does nothing. Please stop calling this method.
> clamp-out (-8.98846567431158e+307, -8.98846567431158e+307, 1.79769313486232e+308, 1.79769313486232e+308)
这个调用产生内部警告的事实也不会增强信心!
有人能确认这种行为吗?我做错了什么吗?