如果你不关心图像内容,PIL 可能有点大材小用了。
我建议解析 python magic 模块的输出:
>>> t = magic.from_file('teste.png')
>>> t
'PNG image data, 782 x 602, 8-bit/color RGBA, non-interlaced'
>>> re.search('(\d+) x (\d+)', t).groups()
('782', '602')
这是 libmagic 的包装器,它读取尽可能少的字节以识别文件类型签名。
脚本的相关版本:
https://raw.githubusercontent.com/scardine/image_size/master/get_image_size.py https://raw.githubusercontent.com/scardine/image_size/master/get_image_size.py
[update]
嗯,不幸的是,当应用于 jpeg 时,上面给出了“'JPEG 图像数据,EXIF 标准 2.21'”。没有图像尺寸! ——亚历克斯·弗林特
看起来 jpeg 是具有魔法抗性的。 :-)
我明白为什么:为了获取 JPEG 文件的图像尺寸,您可能必须读取比 libmagic 喜欢读取的字节更多的字节。
卷起袖子来了这个未经测试的片段(从 GitHub 获取) https://github.com/scardine/image_size不需要第三方模块。
#-------------------------------------------------------------------------------
# Name: get_image_size
# Purpose: extract image dimensions given a file path using just
# core modules
#
# Author: Paulo Scardine (based on code from Emmanuel VAÏSSE)
#
# Created: 26/09/2013
# Copyright: (c) Paulo Scardine 2013
# Licence: MIT
#-------------------------------------------------------------------------------
#!/usr/bin/env python
import os
import struct
class UnknownImageFormat(Exception):
pass
def get_image_size(file_path):
"""
Return (width, height) for a given img file content - no external
dependencies except the os and struct modules from core
"""
size = os.path.getsize(file_path)
with open(file_path) as input:
height = -1
width = -1
data = input.read(25)
if (size >= 10) and data[:6] in ('GIF87a', 'GIF89a'):
# GIFs
w, h = struct.unpack("<HH", data[6:10])
width = int(w)
height = int(h)
elif ((size >= 24) and data.startswith('\211PNG\r\n\032\n')
and (data[12:16] == 'IHDR')):
# PNGs
w, h = struct.unpack(">LL", data[16:24])
width = int(w)
height = int(h)
elif (size >= 16) and data.startswith('\211PNG\r\n\032\n'):
# older PNGs?
w, h = struct.unpack(">LL", data[8:16])
width = int(w)
height = int(h)
elif (size >= 2) and data.startswith('\377\330'):
# JPEG
msg = " raised while trying to decode as JPEG."
input.seek(0)
input.read(2)
b = input.read(1)
try:
while (b and ord(b) != 0xDA):
while (ord(b) != 0xFF): b = input.read(1)
while (ord(b) == 0xFF): b = input.read(1)
if (ord(b) >= 0xC0 and ord(b) <= 0xC3):
input.read(3)
h, w = struct.unpack(">HH", input.read(4))
break
else:
input.read(int(struct.unpack(">H", input.read(2))[0])-2)
b = input.read(1)
width = int(w)
height = int(h)
except struct.error:
raise UnknownImageFormat("StructError" + msg)
except ValueError:
raise UnknownImageFormat("ValueError" + msg)
except Exception as e:
raise UnknownImageFormat(e.__class__.__name__ + msg)
else:
raise UnknownImageFormat(
"Sorry, don't know how to get information from this file."
)
return width, height
[2019年更新]
查看 Rust 实现:https://github.com/scardine/imsz https://github.com/scardine/imsz