Description

Starting from OpenCV3.3 the imdecode function will automatically rotate the image based on the EXIF' orientation flag.

Mat imdecode( InputArray _buf, int flags )
{
    CV_TRACE_FUNCTION();

    Mat buf = _buf.getMat(), img;
    imdecode_( buf, flags, LOAD_MAT, &img );

    /// optionally rotate the data if EXIF' orientation flag says so
    if( !img.empty() && (flags & IMREAD_IGNORE_ORIENTATION) == 0 && flags != IMREAD_UNCHANGED )
    {
        ApplyExifOrientation(buf, img);
    }

    return img;
}

This can be disabled by setting the cv::IMREAD_IGNORE_ORIENTATION flag.

Checklist

Essentials

• Passed code style checking (make lint)
• Changes are complete (i.e. I finished coding on this PR)
• All changes have test coverage
• For user-facing API changes, API doc string has been updated. For new C++ functions in header files, their functionalities and arguments are well-documented.
• To my best knowledge, examples are either not affected by this change, or have been fixed to be compatible with this change

Changes

• add IMREAD_IGNORE_ORIENTATION flag when opencv 3.3 is used.

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