我正在 Django 中开发一个图像上传器。图像上传并保存到磁盘后，
我正在尝试调整保存的图像的大小，同时保持其纵横比。我正在使用 Pillow 进行图像处理/调整大小。当我尝试调整图像大小时出现问题，即使调整大小的图像的长宽比与原始图像的长宽比相同，它也会像素化。
原始保存图像：https://www.dropbox.com/s/80yk6tnwt3xnoun/babu_980604.jpeg https://www.dropbox.com/s/80yk6tnwt3xnoun/babu_980604.jpeg
调整大小的像素图像：https://www.dropbox.com/s/bznodpk4t4xlyqp/babu_736302.large.jpeg https://www.dropbox.com/s/bznodpk4t4xlyqp/babu_736302.large.jpeg
我尝试过谷歌搜索这个问题，并检查了 stackoverflow 上的其他相关链接，
like
如何使用 PIL 调整图像大小并保持其纵横比？ https://stackoverflow.com/questions/273946/how-do-i-resize-an-image-using-pil-and-maintain-its-aspect-ratio
调整图像大小并保持纵横比并使纵向和横向图像的尺寸完全相同？ https://stackoverflow.com/questions/9103257/resize-image-maintaining-aspect-ratio-and-making-portrait-and-landscape-images-e
但问题仍然存在。
版本：
姜戈=1.6.4
枕头=2.4.0
一切都已在 virtualenv 内设置。请帮忙！
PS：我是 Python/Django 世界的新手
这是我的代码片段：
import json
import os
import hashlib
from datetime import datetime
from operator import itemgetter
import random
from random import randint
from django.views.decorators.csrf import csrf_exempt, csrf_protect
from django.http import (HttpResponse, HttpResponseRedirect)
from django.core.context_processors import csrf
from django.core.files.images import get_image_dimensions
from django.shortcuts import render, redirect
from django.forms.models import model_to_dict
from django.views.decorators.csrf import csrf_exempt
from PIL import Image, ImageOps
from django.views.decorators.csrf import csrf_exempt, csrf_protect
import settings
from hashlib import md5
from django import forms
from beardedavenger.models import *
from django.views.decorators.http import require_POST
import pdb
import requests
def imagehandler(requests):
if requests.method == 'POST':
filename = requests.FILES['file'].name
file_extension = filename.split('.')[len(filename.split('.')) - 1].lower()
errors = []
username = 'nit'
global random
#allowed image types are png, jpg, jpeg, gif
if file_extension not in settings.IMAGE_FILE_TYPES:
errors.append('The image file you provided is not valid. Only the following extensions are allowed: %s' % ', '.join(settings.IMAGE_FILE_TYPES))
else:
image = requests.FILES['file']
image_w, image_h = get_image_dimensions(image)
rand = str(random.randint(100000,999999))
with open(settings.MEDIA_ROOT + username + '_' + rand + '.jpeg', 'wb+') as destination:
for chunk in requests.FILES['file'].chunks():
destination.write(chunk)
large_size = (1920, 1200)
infile = settings.MEDIA_ROOT + username + '_' + rand + ".jpeg"
large_file = settings.MEDIA_ROOT + username + '_' + rand +".large"
try:
im = Image.open(infile)
base_width = large_size[0]
aspect_ratio = float(image_w / float(image_h))
new_height = int(base_width / aspect_ratio)
if new_height < 1200:
final_width = base_width
final_height = new_height
else:
final_width = int(aspect_ratio * large_size[1])
final_height = large_size[1]
final_size = (final_width, final_height)
imaged = im.resize((final_width, final_height), Image.ANTIALIAS)
# imaged = ImageOps.fit(im, final_size, Image.ANTIALIAS, centering = (0.5,0.5))
imaged.save(large_file, "JPEG", quality=90)
except IOError:
errors.append('error while resizing image')
if not errors:
response = HttpResponse(json.dumps({'status': 'success','filename': filename }),
mimetype="application/json")
else:
response = HttpResponse(json.dumps({'status': 'failure','errors': errors,'message': 'Error uploading Picture. '}),
mimetype="application/json")
return response
else:
return render(requests, 'upload.html')
更新 ：
我正在使用 Pillow 来调整图像大小和压缩图像。即使保持纵横比，调整大小时图像中也会出现一定程度的暗淡[与原始图像相比，抗锯齿效果比所需的要多]。我将处理库切换到 ImageMagick（针对许多建议不要这样做的帖子！）以及 Wand API (docs.wand-py.org/en/0.3.7/index.html) 来处理我的图像。这个改变就像一个魅力！
