问题描述
在Apple的上，它曾经用来说
On Apple's iOS 6.0 feature page, it used to say
此文字已被移除，因此，我没有找到新的方法在API中用于控制暴露。在 AVCaptureDevice 在曝光设置下没有新的属性/方法为iOS 6.0。你知道我在哪里可以找到曝光的新功能在API？
This text has since been removed, and I can't find new methods in the API for controlling exposure. In class AVCaptureDevice under "Exposure Settings" there is no new property/method for iOS 6.0. Do you know where i can find new features for exposure in API?
推荐答案
这是真的有一个 -exposureMode 属性在 AVCaptureDevice ，但这只是设置模式（关闭/自动/连续），而不是实际的f- ，或ISO。提供曝光控件的照相机应用程序似乎通过后处理来实现。
It's true that there is an -exposureMode property on AVCaptureDevice, but that's only for setting the mode (off/auto/continuous) and not the actual f-stop, SS, or ISO. Camera apps that provide "exposure" control all seem to do it through post-processing.
但是，框架中似乎有未记录的API可以执行此操作。请查看（通过），并注意以下内容方法：
However, it seems there are undocumented APIs in the framework to do this. Check out the full headers for AVCaptureDevice.h (via a class-dump) and note the following methods:
- (void)setManualExposureSupportEnabled:(BOOL)arg1;
- (BOOL)isManualExposureSupportEnabled;
- (void)setExposureGain:(float)arg1;
- (float)exposureGain;
- (void)setExposureDuration:(struct { long long x1; int x2; unsigned int x3; long long x4; })arg1;
- (struct { long long x1; int x2; unsigned int x3; long long x4; })exposureDuration;
- (void)setExposureMode:(int)arg1;
- (int)exposureMode;
- (BOOL)isExposureModeSupported:(int)arg1;
我的猜测是 gain 停止（固定光圈）， duration 是快门速度。我不知道这些是否用于iPhone 5的。
My guess is gain is equivalent f-stop (fixed aperture), and duration is shutter speed. I wonder if these are used for the iPhone 5's low-light boost mode.
您还可以使用，试图将符号拼凑在一起。在 exposureMode 中启用手动控制可能有一个新常量， exposureDuration 似乎也有标志。调用这些时，请务必使用新的 -isExposureModeSupported：并调用 -respondsToSelector：来检查兼容性。
You can also use otool to poke around and try to piece together the symbols. There's likely a new constant in exposureMode for enabling manual control, and exposureDuration seems like it has flags too. When calling these, make sure to use the new -isExposureModeSupported: and also call -respondsToSelector: to check compatibility.
一如既往，使用私人API被苹果所。病，并且被App Store拒绝。可能有一些方法，例如使用 -performSelector：或与rot13字符串或其他他们只对应用程序二进制文件进行静态分析。
As always, using private APIs is frowned upon by Apple and is cause for rejection from the App Store. There might be ways around this, such as hiding the calls using -performSelector: or obc_msgsend with rot13 strings or something, as I'm pretty sure they only do static analysis on the app binary.
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