Question

我正在使用AVFoundation构建自定义相机。除了setExposurePointOfInterest之外，一切都很好。

我在iPhone 5上测试，AVCaptureDevice告诉我BackCamera不支持AVCaptureExposureModeAutoExpose。

如何实施点按以调整曝光？

这是我的代码：

- (void)didTapCameraPreview:(UITapGestureRecognizer *)recognizer {

CGPoint point = [recognizer locationInView:self.view];
CGRect screenRect = [self.view bounds];
CGFloat screenWidth = screenRect.size.width;
CGFloat screenHeight = screenRect.size.height;
double focus_x = point.x/screenWidth;
double focus_y = point.y/screenHeight;

CGPoint touchPoint = CGPointMake(focus_x, focus_y);

AVCaptureDevice *device = (self.captureSession.inputs[0] == self.backCamera) ? self.backCamera.device : self.frontCamera.device;

if (device.isFocusPointOfInterestSupported) {
    NSError *error;
    if ([device lockForConfiguration:&error]) {
        [device setFocusPointOfInterest:touchPoint];
        [device setExposurePointOfInterest:touchPoint];

        [device setFocusMode:AVCaptureFocusModeAutoFocus];
        if ([device isExposureModeSupported:AVCaptureExposureModeAutoExpose]){
            [device setExposureMode:AVCaptureExposureModeAutoExpose];
        }
        [device unlockForConfiguration];
    }
}

}

Answer 1

我在Apple开发者论坛上质疑类似的问题，并得到了Brad Ford（核心媒体工程）的回答，他是苹果公司WWDC中AV Foundation的Camera Capture发言人。

这是他的answer：

<强>正确。 AVCaptureExposureModeAutoExpose，虽然在标题中定义，   目前尚未在任何iOS设备上实施。

但是，您可以通过设置所需的代码在自己的代码中实现它   兴趣点，然后打电话   setExposureMode：AVCaptureExposureModeContinuousAutoExposure，然后   listen（键值观察）的“isAdjustingExposure”属性   AVCaptureDevice知道曝光何时完成调整。尽快   就像这样，将setExposureMode设置为AVCaptureExposureModeLocked。

希望它澄清并帮助！

AVFoundation：isExposureModeSupported为AVCaptureExposureModeAutoExpose返回FALSE

1 个答案: