/usr/share/blender/scripts/blender-thumbnailer.py is in blender-data 2.69-4ubuntu2.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 | #!/usr/bin/python3
# ##### BEGIN GPL LICENSE BLOCK #####
#
# This program 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 2
# 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software Foundation,
# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
#
# ##### END GPL LICENSE BLOCK #####
# <pep8 compliant>
"""
Thumbnailer runs with python 2.6 and 3.x.
To run automatically with nautilus:
gconftool --type boolean --set /desktop/gnome/thumbnailers/application@x-blender/enable true
gconftool --type string --set /desktop/gnome/thumbnailers/application@x-blender/command "/usr/share/blender/scripts/blender-thumbnailer.py %i %o"
"""
import struct
def open_wrapper_get():
""" wrap OS spesific read functionality here, fallback to 'open()'
"""
def open_gio(path, mode):
g_file = gio.File(path).read()
g_file.orig_seek = g_file.seek
def new_seek(offset, whence=0):
return g_file.orig_seek(offset, [1, 0, 2][whence])
g_file.seek = new_seek
return g_file
try:
import gio
return open_gio
except ImportError:
return open
def blend_extract_thumb(path):
import os
open_wrapper = open_wrapper_get()
# def MAKE_ID(tag): ord(tag[0])<<24 | ord(tag[1])<<16 | ord(tag[2])<<8 | ord(tag[3])
REND = 1145980242 # MAKE_ID(b'REND')
TEST = 1414743380 # MAKE_ID(b'TEST')
blendfile = open_wrapper(path, 'rb')
head = blendfile.read(12)
if head[0:2] == b'\x1f\x8b': # gzip magic
import gzip
blendfile.close()
blendfile = gzip.GzipFile('', 'rb', 0, open_wrapper(path, 'rb'))
head = blendfile.read(12)
if not head.startswith(b'BLENDER'):
blendfile.close()
return None, 0, 0
is_64_bit = (head[7] == b'-'[0])
# true for PPC, false for X86
is_big_endian = (head[8] == b'V'[0])
# blender pre 2.5 had no thumbs
if head[9:11] <= b'24':
return None, 0, 0
sizeof_bhead = 24 if is_64_bit else 20
int_endian_pair = '>ii' if is_big_endian else '<ii'
while True:
bhead = blendfile.read(sizeof_bhead)
if len(bhead) < sizeof_bhead:
return None, 0, 0
code, length = struct.unpack(int_endian_pair, bhead[0:8]) # 8 == sizeof(int) * 2
if code == REND:
blendfile.seek(length, os.SEEK_CUR)
else:
break
if code != TEST:
return None, 0, 0
try:
x, y = struct.unpack(int_endian_pair, blendfile.read(8)) # 8 == sizeof(int) * 2
except struct.error:
return None, 0, 0
length -= 8 # sizeof(int) * 2
if length != x * y * 4:
return None, 0, 0
image_buffer = blendfile.read(length)
if len(image_buffer) != length:
return None, 0, 0
return image_buffer, x, y
def write_png(buf, width, height):
import zlib
# reverse the vertical line order and add null bytes at the start
width_byte_4 = width * 4
raw_data = b"".join(b'\x00' + buf[span:span + width_byte_4] for span in range((height - 1) * width * 4, -1, - width_byte_4))
def png_pack(png_tag, data):
chunk_head = png_tag + data
return struct.pack("!I", len(data)) + chunk_head + struct.pack("!I", 0xFFFFFFFF & zlib.crc32(chunk_head))
return b"".join([
b'\x89PNG\r\n\x1a\n',
png_pack(b'IHDR', struct.pack("!2I5B", width, height, 8, 6, 0, 0, 0)),
png_pack(b'IDAT', zlib.compress(raw_data, 9)),
png_pack(b'IEND', b'')])
if __name__ == '__main__':
import sys
if len(sys.argv) < 3:
print("Expected 2 arguments <input.blend> <output.png>")
else:
file_in = sys.argv[-2]
buf, width, height = blend_extract_thumb(file_in)
if buf:
file_out = sys.argv[-1]
f = open(file_out, "wb")
f.write(write_png(buf, width, height))
f.close()
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