ios - GPUImage 前置摄像头点击对焦为什么不起作用？

Question

我已经实现了下面的代码来启用点击对焦相机。它在后置摄像头上工作正常，但在使用前置摄像头时失败，因为_videoCamera.inputCamera.isFocusPointOfInterestSupported 为假。

错了为什么？请帮助我。

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {

    UITouch *touch = [touches anyObject];
    CGPoint touchPoint = [touch locationInView:self.view];

    if([_videoCamera.inputCamera isFocusPointOfInterestSupported]&&[_videoCamera.inputCamera isFocusModeSupported:AVCaptureFocusModeAutoFocus])
    {

        if([_videoCamera.inputCamera lockForConfiguration :nil])
        {
            [_videoCamera.inputCamera setFocusPointOfInterest :touchPoint];
            [_videoCamera.inputCamera setFocusMode :AVCaptureFocusModeLocked];

            if([_videoCamera.inputCamera isExposurePointOfInterestSupported])
            {    CGRect screenRect = [[UIScreen mainScreen] bounds];
                CGFloat screenWidth = screenRect.size.width;
                CGFloat screenHeight = screenRect.size.height;
                double focus_x = touchPoint.x/screenWidth;
                double focus_y = touchPoint.y/screenHeight;
                [_videoCamera.inputCamera setExposurePointOfInterest:CGPointMake(focus_x,focus_y)];
                [_videoCamera.inputCamera setFocusMode:AVCaptureFocusModeAutoFocus];
                if ([_videoCamera.inputCamera isExposureModeSupported:AVCaptureExposureModeAutoExpose]){
                    [_videoCamera.inputCamera setExposureMode:AVCaptureExposureModeAutoExpose];
                }

            }
            [_videoCamera.inputCamera unlockForConfiguration];
        }
    }

}

Answer 1

前置摄像头是定焦的。没有自动对焦，不关注兴趣点。这正是 iOS 在您调用 isFocusPointOfInterestSupported 时通过返回 NO 告诉您的内容。