libervia-backend/sat/tools/image.py
2020-03-22 12:52:43 +01:00

87 lines
3.1 KiB
Python

#!/usr/bin/env python3
# SàT: an XMPP client
# Copyright (C) 2009-2020 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
from PIL import Image
from pathlib import Path
from twisted.internet import threads
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 _resizeBlocking(image_path, new_size, dest=None):
im_path = Path(image_path)
im = Image.open(im_path)
resized = im.resize(new_size, Image.LANCZOS)
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):
"""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
- Path: path to the file to create/overwrite
- file: a file object which must be opened for writing in binary mode
@return (Path): path of the resized file.
The image at this path should be deleted after use
"""
return threads.deferToThread(_resizeBlocking, image_path, new_size, dest)