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@mayankgupta804
Forked from bmamouri/getimageinfo.py
Created August 8, 2017 12:15
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Source code for getImageInfo function to get the dimension of an image from the header
# coding:utf-8
# From http://code.google.com/p/plsamples/source/browse/trunk/GrandMonde/getimageinfo.py
import StringIO
import struct
from reseekfile import ReseekFile
def getImageInfo(datastream):
datastream = ReseekFile.ReseekFile(datastream)
data = str(datastream.read(30))
size = len(data)
height = -1
width = -1
content_type = ''
# handle GIFs
if (size >= 10) and data[:6] in ('GIF87a', 'GIF89a'):
# Check to see if content_type is correct
content_type = 'image/gif'
w, h = struct.unpack("<HH", data[6:10])
width = int(w)
height = int(h)
# See PNG 2. Edition spec (http://www.w3.org/TR/PNG/)
# Bytes 0-7 are below, 4-byte chunk length, then 'IHDR'
# and finally the 4-byte width, height
elif ((size >= 24) and data.startswith('\211PNG\r\n\032\n')
and (data[12:16] == 'IHDR')):
content_type = 'image/png'
w, h = struct.unpack(">LL", data[16:24])
width = int(w)
height = int(h)
# Maybe this is for an older PNG version.
elif (size >= 16) and data.startswith('\211PNG\r\n\032\n'):
# Check to see if we have the right content type
content_type = 'image/png'
w, h = struct.unpack(">LL", data[8:16])
width = int(w)
height = int(h)
# handle JPEGs
elif (size >= 2) and data.startswith('\377\330'):
content_type = 'image/jpeg'
jpeg = StringIO.StringIO(data)
jpeg.read(2)
b = jpeg.read(1)
try:
while (b and ord(b) != 0xDA):
while (ord(b) != 0xFF): b = jpeg.read(1)
while (ord(b) == 0xFF): b = jpeg.read(1)
if (ord(b) >= 0xC0 and ord(b) <= 0xC3):
jpeg.read(3)
h, w = struct.unpack(">HH", jpeg.read(4))
break
else:
jpeg.read(int(struct.unpack(">H", jpeg.read(2))[0])-2)
b = jpeg.read(1)
width = int(w)
height = int(h)
except struct.error:
pass
except ValueError:
pass
return content_type, width, height
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