view sat/tools/image.py @ 3582:71516731d0aa

core (memory/sqla): database migration using Alembic: Alembic database migration tool, which is the recommended one for SQLAlchemy has been integrated. When a database is created, it will be used to stamp to current (head) revision, otherwise, DB will be checked to see if it needs to be updated, and upgrade will be triggered if necessary.
author Goffi <goffi@goffi.org>
date Fri, 25 Jun 2021 17:55:23 +0200
parents 7550ae9cfbac
children 524856bd7b19
line wrap: on
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#!/usr/bin/env python3

# Libervia: an XMPP client
# Copyright (C) 2009-2021 Jérôme Poisson (goffi@goffi.org)

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.

# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

"""Methods to manipulate images"""

import tempfile
import mimetypes
from PIL import Image, ImageOps
from pathlib import Path
from twisted.internet import threads
from sat.core.i18n import _
from sat.core import exceptions
from sat.core.log import getLogger

log = getLogger(__name__)

try:
    import cairosvg
except Exception as e:
    log.warning(_("SVG support not available, please install cairosvg: {e}").format(
        e=e))
    cairosvg = None


def check(host, path, max_size=None):
    """Analyze image and return a report

    report will indicate if image is too large, and the recommended new size if this is
    the case
    @param host: SàT instance
    @param path(str, pathlib.Path): image to open
    @param max_size(tuple[int, int]): maximum accepted size of image
        None to use value set in config
    @return dict: report on image, with following keys:
        - too_large: true if image is oversized
        - recommended_size: if too_large is True, recommended size to use
    """
    report = {}
    image = Image.open(path)
    if max_size is None:
        max_size = tuple(host.memory.getConfig(None, "image_max", (1200, 720)))
    if image.size > max_size:
        report['too_large'] = True
        if image.size[0] > max_size[0]:
            factor = max_size[0] / image.size[0]
            if image.size[1] * factor > max_size[1]:
                factor = max_size[1] / image.size[1]
        else:
            factor = max_size[1] / image.size[1]
        report['recommended_size'] = [int(image.width*factor), int(image.height*factor)]
    else:
        report['too_large'] = False

    return report


def _resize_blocking(image_path, new_size, dest, fix_orientation):
    im_path = Path(image_path)
    im = Image.open(im_path)
    resized = im.resize(new_size, Image.LANCZOS)
    if fix_orientation:
        resized = ImageOps.exif_transpose(resized)

    if dest is None:
        dest = tempfile.NamedTemporaryFile(suffix=im_path.suffix, delete=False)
    elif isinstance(dest, Path):
        dest = dest.open('wb')

    with dest as f:
        resized.save(f, format=im.format)

    return Path(f.name)


def resize(image_path, new_size, dest=None, fix_orientation=True):
    """Resize an image to a new file, and return its path

    @param image_path(str, Path): path of the original image
    @param new_size(tuple[int, int]): size to use for new image
    @param dest(None, Path, file): where the resized image must be stored, can be:
        - None: use a temporary file
            file will be converted to PNG
        - Path: path to the file to create/overwrite
        - file: a file object which must be opened for writing in binary mode
    @param fix_orientation: if True, use EXIF data to set orientation
    @return (Path): path of the resized file.
        The image at this path should be deleted after use
    """
    return threads.deferToThread(
        _resize_blocking, image_path, new_size, dest, fix_orientation)


def _convert_blocking(image_path, dest, extra):
    media_type = mimetypes.guess_type(str(image_path), strict=False)[0]

    if dest is None:
        dest = tempfile.NamedTemporaryFile(suffix=".png", delete=False)
        filepath = Path(dest.name)
    elif isinstance(dest, Path):
        filepath = dest
    else:
        # we should have a file-like object
        try:
            name = dest.name
        except AttributeError:
            name = None
        if name:
            try:
                filepath = Path(name)
            except TypeError:
                filepath = Path('noname.png')
        else:
            filepath = Path('noname.png')

    if media_type == "image/svg+xml":
        if cairosvg is None:
            raise exceptions.MissingModule(
                f"Can't convert SVG image at {image_path} due to missing CairoSVG module")
        width, height = extra.get('width'), extra.get('height')
        cairosvg.svg2png(
            url=str(image_path), write_to=dest,
            output_width=width, output_height=height
        )
    else:
        suffix = filepath.suffix
        if not suffix:
            raise ValueError(
                "A suffix is missing for destination, it is needed to determine file "
                "format")
        if not suffix in Image.EXTENSION:
            Image.init()
        try:
            im_format = Image.EXTENSION[suffix]
        except KeyError:
            raise ValueError(
                "Dest image format can't be determined, {suffix!r} suffix is unknown"
            )
        im = Image.open(image_path)
        im.save(dest, format=im_format)

    log.debug(f"image {image_path} has been converted to {filepath}")
    return filepath


def convert(image_path, dest=None, extra=None):
    """Convert an image to a new file, and return its path

    @param image_path(str, Path): path of the image to convert
    @param dest(None, Path, file): where the converted image must be stored, can be:
        - None: use a temporary file
        - Path: path to the file to create/overwrite
        - file: a file object which must be opened for writing in binary mode
    @param extra(None, dict): conversion options
        if image_path link to a SVG file, following options can be used:
                - width: destination width
                - height: destination height
    @return (Path): path of the converted file.
        a generic name is used if dest is an unnamed file like object
    """
    image_path = Path(image_path)
    if not image_path.is_file():
        raise ValueError(f"There is no file at {image_path}!")
    if extra is None:
        extra = {}
    return threads.deferToThread(_convert_blocking, image_path, dest, extra)


def __fix_orientation_blocking(image_path):
    im = Image.open(image_path)
    im_format = im.format
    exif = im.getexif()
    orientation = exif.get(0x0112)
    if orientation is None or orientation<2:
        # nothing to do
        return False
    im = ImageOps.exif_transpose(im)
    im.save(image_path, im_format)
    log.debug(f"image {image_path} orientation has been fixed")
    return True


def fix_orientation(image_path: Path) -> bool:
    """Apply orientation found in EXIF data if any

    @param image_path: image location, image will be modified in place
    @return True if image has been modified
    """
    return threads.deferToThread(__fix_orientation_blocking, image_path)


def guess_type(source):
    """Guess image media type

    @param source(str, Path, file): image to guess type
    @return (str, None): media type, or None if we can't guess
    """
    if isinstance(source, str):
        source = Path(source)

    if isinstance(source, Path):
        # we first try to guess from file name
        media_type = mimetypes.guess_type(source, strict=False)[0]
        if media_type is not None:
            return media_type

    # file name is not enough, we try to open it
    img = Image.open(source)
    try:
        return Image.MIME[img.format]
    except KeyError:
        return None