media/image.py

import io
import logging
from PIL import Image, ImageEnhance, ExifTags

try:
    from config import APP_NAME as ROOT_LOGGER_NAME
except ImportError:
    ROOT_LOGGER_NAME = 'root'
logger = logging.getLogger(ROOT_LOGGER_NAME).getChild(__name__)


ORIENTATION_NORMAL = 1
ORIENTATION_VERTICAL_MIRRORED = 2
ORIENTATION_HALF_ROTATED = 3
ORIENTATION_HORIZONTAL_MIRRORED = 4
ORIENTATION_LEFT_ROTATED = 6
ORIENTATION_RIGHT_ROTATED = 8

JOIN_TOP_LEFT = 1
JOIN_TOP_RIGHT = 2
JOIN_BOT_LEFT = 3
JOIN_BOT_RIGHT = 4
JOIN_CENTER = 5


class image(object):
    def __init__(self, media_instance=None):
        if media_instance is not None:
            self.load_from_file(media_instance)
        else:
            self._im = None

    def load_from_file(self, media_instance):
        from media.convert import get_pil_image
        #
        self._im = get_pil_image(media_instance)
        if self._im is None:
            return False
        try:
            self._exif = dict(self._im._getexif().items())
        except AttributeError:
            self._exif = {}
        if type(self._im) is not Image.Image:
            self._im = self._im.copy()
        logger.debug('loading image from %s', repr(media_instance))
        return True

    def save(self, full_path):
        if self._im is None:
            logger.warning('No image available to be saved (%s)', repr(full_path))
            return False
        else:
            logger.debug('Saving image to %s', repr(full_path))
            with open(full_path, 'w') as fh:
                im = self._im.convert('RGB')
                im.save(fh, 'JPEG')
        return True

    def image_data(self):
        im = self._im.copy().convert('RGB')
        output = io.BytesIO()
        im.save(output, format='JPEG')
        return output.getvalue()

    def resize(self, max_size):
        if self._im is None:
            logger.warning('No image available to be resized')
            return False
        else:
            logger.debug('Resizing picture to max %d pixel in whatever direction', max_size)
            x, y = self._im.size
            xy_max = max(x, y)
            self._im = self._im.resize((int(x * float(max_size) / xy_max), int(y * float(max_size) / xy_max)), Image.NEAREST).rotate(0)
        return True

    def rotate_by_orientation(self, orientation=None):
        if self._im is None:
            logger.warning('No image available, rotation not possible')
            return False

        if orientation is None:
            exif_tags = dict((v, k) for k, v in ExifTags.TAGS.items())
            try:
                orientation = self._exif[exif_tags['Orientation']]
                logger.debug("No orientation given, orientation %s extract from exif data", repr(orientation))
            except KeyError:
                return False

        if orientation == ORIENTATION_HALF_ROTATED:
            angle = 180
        elif orientation == ORIENTATION_LEFT_ROTATED:
            angle = 270
        elif orientation == ORIENTATION_RIGHT_ROTATED:
            angle = 90
        else:
            if type(orientation) == int and orientation > 8:
                logger.warning('Orientation %s unknown for rotation', repr(orientation))
            return False
        logger.debug('Rotating picture by %d (deg)', angle)
        self._im = self._im.rotate(angle, expand=True)
        return True

    def join(self, join_image, join_pos=JOIN_TOP_RIGHT, opacity=0.7):
        from media.convert import get_pil_image

        def rgba_copy(im):
            if im.mode != 'RGBA':
                return im.convert('RGBA')
            else:
                return im.copy()

        if self._im is None:
            logger.warning('No image available, joining not possible')
            return False

        # ensure type of join_image is PIL.Image
        join_image = get_pil_image(join_image)
        if join_image is None:
            logger.warning('Image to be joined is not supported %s', repr(join_image))
            return False

        im2 = rgba_copy(join_image)
        # change opacity of im2
        alpha = im2.split()[3]
        alpha = ImageEnhance.Brightness(alpha).enhance(opacity)
        im2.putalpha(alpha)

        self._im = rgba_copy(self._im)

        # create a transparent layer
        layer = Image.new('RGBA', self._im.size, (0, 0, 0, 0))
        # draw im2 in layer
        if join_pos == JOIN_TOP_LEFT:
            layer.paste(im2, (0, 0))
        elif join_pos == JOIN_TOP_RIGHT:
            layer.paste(im2, ((self._im.size[0] - im2.size[0]), 0))
        elif join_pos == JOIN_BOT_LEFT:
            layer.paste(im2, (0, (self._im.size[1] - im2.size[1])))
        elif join_pos == JOIN_BOT_RIGHT:
            layer.paste(im2, ((self._im.size[0] - im2.size[0]), (self._im.size[1] - im2.size[1])))
        elif join_pos == JOIN_CENTER:
            layer.paste(im2, (int((self._im.size[0] - im2.size[0]) / 2), int((self._im.size[1] - im2.size[1]) / 2)))
        else:
            logger.warning("Join position value %s is not supported", join_pos)
            return False

        logger.debug('Joining two images')
        self._im = Image.composite(layer, self._im, layer)

        return True