[libcamera-devel] [PATCH v4 2/8] android: jpeg: exif: Fix setOrientation EXIF values

[Jacopo Mondi]

Hi Paul,

On Mon, Jan 25, 2021 at 04:14:38PM +0900, Paul Elder wrote:
> The input to setOrientation is angle clockwise from the sensor
> orientation, while the EXIF output values were swapped for 90
> and 270 degrees.
>
> From the EXIF spec:
>
> 6 = The 0th row is the visual right-hand side of the image, and the
>     0th column is the visual top.
> 8 = The 0th row is the visual left-hand side of the image, and the
>     0th column is the visual bottom.
>
> 6 should be 90 degrees clockwise, while 8 should 270 degrees clockwise.
> Fix this.
>
> As Android defines the rotation as the clockwise angle by which the
> image needs to be rotated to appear in the correct orientation on the
> device screen, the previous values would be correct if the input angle
> was from the camera orientation. Since the correct input should be the
> requested JPEG orientation, these new values are the correct ones.
>

Thanks for the much more clear commit message.

If I got this right, this has nothing to do with the camera
rotation, but only depends on the ANDROID_JPEG_ORIENTATION control
value.

With this confirmed:
Reviewed-by: Jacopo Mondi <jacopo at jmondi.org>

Thanks
   j

> Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
> Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
>
> ---
> No change in v3
>
> Changes in v2
> - expand commit message
> ---
>  src/android/jpeg/exif.cpp | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/src/android/jpeg/exif.cpp b/src/android/jpeg/exif.cpp
> index 89343323..204a237a 100644
> --- a/src/android/jpeg/exif.cpp
> +++ b/src/android/jpeg/exif.cpp
> @@ -306,13 +306,13 @@ void Exif::setOrientation(int orientation)
>  		value = 1;
>  		break;
>  	case 90:
> -		value = 8;
> +		value = 6;
>  		break;
>  	case 180:
>  		value = 3;
>  		break;
>  	case 270:
> -		value = 6;
> +		value = 8;
>  		break;
>  	}
>
> --
> 2.27.0
>
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