jpeg_rotate_with_exif_on_save_patch.py

import logging
import sys

from PIL import Image, JpegImagePlugin
from PIL.JpegImagePlugin import JpegImageFile
import six

__all__ = [
    'ApplyOrientationError',
    'Image',
]

log = logging.getLogger(__name__)


def flip_horizontal(im):
    return im.transpose(Image.FLIP_LEFT_RIGHT)


def flip_vertical(im):
    return im.transpose(Image.FLIP_TOP_BOTTOM)


def rotate_180(im):
    return im.transpose(Image.ROTATE_180)


def rotate_90(im):
    return im.transpose(Image.ROTATE_90)


def rotate_270(im):
    return im.transpose(Image.ROTATE_270)


def transpose(im):
    return rotate_90(flip_horizontal(im))


def transverse(im):
    return rotate_90(flip_vertical(im))


orientation_funcs = [
    None,
    lambda x: x,
    flip_horizontal,
    rotate_180,
    flip_vertical,
    transpose,
    rotate_270,
    transverse,
    rotate_90,
]
kOrientationEXIFTag = 0x0112


class ApplyOrientationError(Exception):
    pass


def apply_orientation(im):
    """
    Extract the oritentation EXIF tag from the image, which should be a PIL
    Image instance, and if there is an orientation tag that would rotate the
    image, apply that rotation to the Image instance given to do an in-place
    rotation.

    :param Image im: Image instance to inspect
    :return: A transposed image instance

    Raises ApplyOrientationError if an error occurs
    """
    try:
        exif = im._getexif()
    except AttributeError:
        six.reraise(ApplyOrientationError, e, sys.exc_info()[2])

    if not exif:
        six.reraise(ApplyOrientationError, e, sys.exc_info()[2])

    log.debug('EXIF data found')
    try:
        orientation = exif[kOrientationEXIFTag]
    except IndexError:
        six.reraise(ApplyOrientationError, e, sys.exc_info()[2])

    try:
        return orientation_funcs[orientation](im)
    except Exception as e:
        six.reraise(ApplyOrientationError, e, sys.exc_info()[2])


def save_applied(im, fp, filename):
    # encoderinfo gets removed so save it
    try:
        old_encoderinfo = im.encoderinfo
    except AttributeError:
        old_encoderinfo = {}

    try:
        im = apply_orientation(im)
    except ApplyOrientationError:
        pass

    im.encoderinfo = old_encoderinfo
    JpegImagePlugin._save(im, fp, filename)


Image.register_save(JpegImageFile.format, save_applied)