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imagescale-m.py
executable file
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imagescale-m.py
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#!/usr/bin/env python3
# Copyright © 2012-13 Qtrac Ltd. All rights reserved.
# This program or module is free software: you can redistribute it
# and/or modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version. It is provided for
# educational purposes and 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
# General Public License for more details.
import sys
if sys.version_info < (3, 2):
print("requires Python 3.2+ for concurrent.futures")
sys.exit(1)
import argparse
import collections
import concurrent.futures
import math
import multiprocessing
import os
import Image
import Qtrac
Result = collections.namedtuple("Result", "copied scaled name") # 单个图形的结果
Summary = collections.namedtuple("Summary", "todo copied scaled canceled") # 所有图形的结果汇总
def main():
size, smooth, source, target, concurrency = handle_commandline()
Qtrac.report("starting...")
summary = scale(size, smooth, source, target, concurrency)
summarize(summary, concurrency)
def handle_commandline():
parser = argparse.ArgumentParser()
parser.add_argument("-c", "--concurrency", type=int,
default=multiprocessing.cpu_count(),
help="specify the concurrency (for debugging and "
"timing) [default: %(default)d]")
parser.add_argument("-s", "--size", default=400, type=int,
help="make a scaled image that fits the given dimension "
"[default: %(default)d]")
parser.add_argument("-S", "--smooth", action="store_true",
help="use smooth scaling (slow but good for text)")
parser.add_argument("source",
help="the directory containing the original .xpm images")
parser.add_argument("target",
help="the directory for the scaled .xpm images")
args = parser.parse_args()
source = os.path.abspath(args.source)
target = os.path.abspath(args.target)
if source == target:
args.error("source and target must be different")
if not os.path.exists(args.target):
os.makedirs(target)
return args.size, args.smooth, source, target, args.concurrency
def scale(size, smooth, source, target, concurrency):
futures = set()
with concurrent.futures.ProcessPoolExecutor(
max_workers=concurrency) as executor:
for sourceImage, targetImage in get_jobs(source, target):
future = executor.submit(scale_one, size, smooth, sourceImage,
targetImage)
futures.add(future)
summary = wait_for(futures)
if summary.canceled:
executor.shutdown()
return summary
# if we caught the KeyboardInterrupt in this function we'd lose the
# accumulated todo, copied, scaled counts.
def get_jobs(source, target):
for name in os.listdir(source):
yield os.path.join(source, name), os.path.join(target, name)
def wait_for(futures):
canceled = False
copied = scaled = 0
try:
for future in concurrent.futures.as_completed(futures):
err = future.exception()
if err is None:
result = future.result()
copied += result.copied
scaled += result.scaled
Qtrac.report("{} {}".format("copied" if result.copied else
"scaled", os.path.basename(result.name)))
elif isinstance(err, Image.Error):
Qtrac.report(str(err), True)
else:
raise err # Unanticipated
except KeyboardInterrupt:
Qtrac.report("canceling...")
canceled = True
for future in futures:
future.cancel()
return Summary(len(futures), copied, scaled, canceled)
def scale_one(size, smooth, sourceImage, targetImage):
"""缩小单个图片
Arguments:
size {[type]} -- [description]
smooth {[type]} -- [description]
sourceImage {[type]} -- [description]
targetImage {[type]} -- [description]
Returns:
[type] -- [description]
"""
oldImage = Image.from_file(sourceImage)
if oldImage.width <= size and oldImage.height <= size:
oldImage.save(targetImage)
return Result(1, 0, targetImage)
else:
if smooth:
scale = min(size / oldImage.width, size / oldImage.height)
newImage = oldImage.scale(scale)
else:
stride = int(math.ceil(max(oldImage.width / size,
oldImage.height / size)))
newImage = oldImage.subsample(stride)
newImage.save(targetImage)
return Result(0, 1, targetImage)
def summarize(summary, concurrency):
message = "copied {} scaled {} ".format(summary.copied, summary.scaled)
difference = summary.todo - (summary.copied + summary.scaled)
if difference:
message += "skipped {} ".format(difference)
message += "using {} processes".format(concurrency)
if summary.canceled:
message += " [canceled]"
Qtrac.report(message)
print()
if __name__ == "__main__":
main()