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
156
157
158
159
160
161
162
163
164
165
166
167
168
|
#
# The Python Imaging Library.
# $Id$
#
# PPM support for PIL
#
# History:
# 96-03-24 fl Created
# 98-03-06 fl Write RGBA images (as RGB, that is)
#
# Copyright (c) Secret Labs AB 1997-98.
# Copyright (c) Fredrik Lundh 1996.
#
# See the README file for information on usage and redistribution.
#
from . import Image, ImageFile
# __version__ is deprecated and will be removed in a future version. Use
# PIL.__version__ instead.
__version__ = "0.2"
#
# --------------------------------------------------------------------
b_whitespace = b"\x20\x09\x0a\x0b\x0c\x0d"
MODES = {
# standard
b"P4": "1",
b"P5": "L",
b"P6": "RGB",
# extensions
b"P0CMYK": "CMYK",
# PIL extensions (for test purposes only)
b"PyP": "P",
b"PyRGBA": "RGBA",
b"PyCMYK": "CMYK",
}
def _accept(prefix):
return prefix[0:1] == b"P" and prefix[1] in b"0456y"
##
# Image plugin for PBM, PGM, and PPM images.
class PpmImageFile(ImageFile.ImageFile):
format = "PPM"
format_description = "Pbmplus image"
def _token(self, s=b""):
while True: # read until next whitespace
c = self.fp.read(1)
if not c or c in b_whitespace:
break
if c > b"\x79":
raise ValueError("Expected ASCII value, found binary")
s = s + c
if len(s) > 9:
raise ValueError("Expected int, got > 9 digits")
return s
def _open(self):
# check magic
s = self.fp.read(1)
if s != b"P":
raise SyntaxError("not a PPM file")
magic_number = self._token(s)
mode = MODES[magic_number]
self.custom_mimetype = {
b"P4": "image/x-portable-bitmap",
b"P5": "image/x-portable-graymap",
b"P6": "image/x-portable-pixmap",
}.get(magic_number)
if mode == "1":
self.mode = "1"
rawmode = "1;I"
else:
self.mode = rawmode = mode
for ix in range(3):
while True:
while True:
s = self.fp.read(1)
if s not in b_whitespace:
break
if s == b"":
raise ValueError("File does not extend beyond magic number")
if s != b"#":
break
s = self.fp.readline()
s = int(self._token(s))
if ix == 0:
xsize = s
elif ix == 1:
ysize = s
if mode == "1":
break
elif ix == 2:
# maxgrey
if s > 255:
if not mode == "L":
raise ValueError("Too many colors for band: %s" % s)
if s < 2 ** 16:
self.mode = "I"
rawmode = "I;16B"
else:
self.mode = "I"
rawmode = "I;32B"
self._size = xsize, ysize
self.tile = [("raw", (0, 0, xsize, ysize), self.fp.tell(), (rawmode, 0, 1))]
#
# --------------------------------------------------------------------
def _save(im, fp, filename):
if im.mode == "1":
rawmode, head = "1;I", b"P4"
elif im.mode == "L":
rawmode, head = "L", b"P5"
elif im.mode == "I":
if im.getextrema()[1] < 2 ** 16:
rawmode, head = "I;16B", b"P5"
else:
rawmode, head = "I;32B", b"P5"
elif im.mode == "RGB":
rawmode, head = "RGB", b"P6"
elif im.mode == "RGBA":
rawmode, head = "RGB", b"P6"
else:
raise IOError("cannot write mode %s as PPM" % im.mode)
fp.write(head + ("\n%d %d\n" % im.size).encode("ascii"))
if head == b"P6":
fp.write(b"255\n")
if head == b"P5":
if rawmode == "L":
fp.write(b"255\n")
elif rawmode == "I;16B":
fp.write(b"65535\n")
elif rawmode == "I;32B":
fp.write(b"2147483648\n")
ImageFile._save(im, fp, [("raw", (0, 0) + im.size, 0, (rawmode, 0, 1))])
# ALTERNATIVE: save via builtin debug function
# im._dump(filename)
#
# --------------------------------------------------------------------
Image.register_open(PpmImageFile.format, PpmImageFile, _accept)
Image.register_save(PpmImageFile.format, _save)
Image.register_extensions(PpmImageFile.format, [".pbm", ".pgm", ".ppm", ".pnm"])
Image.register_mime(PpmImageFile.format, "image/x-portable-anymap")
|
