Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.11/site-packages/PIL/PpmImagePlugin.py: 76%
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1#
2# The Python Imaging Library.
3# $Id$
4#
5# PPM support for PIL
6#
7# History:
8# 96-03-24 fl Created
9# 98-03-06 fl Write RGBA images (as RGB, that is)
10#
11# Copyright (c) Secret Labs AB 1997-98.
12# Copyright (c) Fredrik Lundh 1996.
13#
14# See the README file for information on usage and redistribution.
15#
16from __future__ import annotations
18__lazy_modules__ = {"PIL._binary", "math"}
20import math
22from . import Image, ImageFile
23from ._binary import i16be as i16
24from ._binary import o8
25from ._binary import o32le as o32
27TYPE_CHECKING = False
28if TYPE_CHECKING:
29 from typing import IO
31#
32# --------------------------------------------------------------------
34b_whitespace = b"\x20\x09\x0a\x0b\x0c\x0d"
36MODES = {
37 # standard
38 b"P1": "1",
39 b"P2": "L",
40 b"P3": "RGB",
41 b"P4": "1",
42 b"P5": "L",
43 b"P6": "RGB",
44 # extensions
45 b"P0CMYK": "CMYK",
46 b"Pf": "F",
47 # PIL extensions (for test purposes only)
48 b"PyP": "P",
49 b"PyRGBA": "RGBA",
50 b"PyCMYK": "CMYK",
51}
54def _accept(prefix: bytes) -> bool:
55 return len(prefix) >= 2 and prefix.startswith(b"P") and prefix[1] in b"0123456fy"
58##
59# Image plugin for PBM, PGM, and PPM images.
62class PpmImageFile(ImageFile.ImageFile):
63 format = "PPM"
64 format_description = "Pbmplus image"
66 def _read_magic(self) -> bytes:
67 assert self.fp is not None
69 magic = b""
70 # read until whitespace or longest available magic number
71 for _ in range(6):
72 c = self.fp.read(1)
73 if not c or c in b_whitespace:
74 break
75 magic += c
76 return magic
78 def _read_token(self) -> bytes:
79 assert self.fp is not None
81 token = b""
82 while len(token) <= 10: # read until next whitespace or limit of 10 characters
83 c = self.fp.read(1)
84 if not c:
85 break
86 elif c in b_whitespace: # token ended
87 if not token:
88 # skip whitespace at start
89 continue
90 break
91 elif c == b"#":
92 # ignores rest of the line; stops at CR, LF or EOF
93 while self.fp.read(1) not in b"\r\n":
94 pass
95 continue
96 token += c
97 if not token:
98 # Token was not even 1 byte
99 msg = "Reached EOF while reading header"
100 raise ValueError(msg)
101 elif len(token) > 10:
102 msg_too_long = b"Token too long in file header: %s" % token
103 raise ValueError(msg_too_long)
104 return token
106 def _open(self) -> None:
107 assert self.fp is not None
109 magic_number = self._read_magic()
110 try:
111 mode = MODES[magic_number]
112 except KeyError:
113 msg = "not a PPM file"
114 raise SyntaxError(msg)
115 self._mode = mode
117 if magic_number in (b"P1", b"P4"):
118 self.custom_mimetype = "image/x-portable-bitmap"
119 elif magic_number in (b"P2", b"P5"):
120 self.custom_mimetype = "image/x-portable-graymap"
121 elif magic_number in (b"P3", b"P6"):
122 self.custom_mimetype = "image/x-portable-pixmap"
124 self._size = int(self._read_token()), int(self._read_token())
126 decoder_name = "raw"
127 if magic_number in (b"P1", b"P2", b"P3"):
128 decoder_name = "ppm_plain"
130 args: str | tuple[str | int, ...]
131 if mode == "1":
132 args = "1;I"
133 elif mode == "F":
134 scale = float(self._read_token())
135 if scale == 0.0 or not math.isfinite(scale):
136 msg = "scale must be finite and non-zero"
137 raise ValueError(msg)
138 self.info["scale"] = abs(scale)
140 rawmode = "F;32F" if scale < 0 else "F;32BF"
141 args = (rawmode, 0, -1)
142 else:
143 maxval = int(self._read_token())
144 if not 0 < maxval < 65536:
145 msg = "maxval must be greater than 0 and less than 65536"
146 raise ValueError(msg)
147 if maxval > 255 and mode == "L":
148 self._mode = "I"
150 rawmode = mode
151 if decoder_name != "ppm_plain":
152 # If maxval matches a bit depth, use the raw decoder directly
153 if maxval == 65535 and mode == "L":
154 rawmode = "I;16B"
155 elif maxval != 255:
156 decoder_name = "ppm"
158 args = rawmode if decoder_name == "raw" else (rawmode, maxval)
159 self.tile = [ImageFile._Tile(decoder_name, None, self.fp.tell(), args)]
162#
163# --------------------------------------------------------------------
166class PpmPlainDecoder(ImageFile.PyDecoder):
167 _pulls_fd = True
168 _comment_spans: bool
170 def _read_block(self) -> bytes:
171 assert self.fd is not None
173 return self.fd.read(ImageFile.SAFEBLOCK)
175 def _find_comment_end(self, block: bytes, start: int = 0) -> int:
176 a = block.find(b"\n", start)
177 b = block.find(b"\r", start)
178 return min(a, b) if a * b > 0 else max(a, b) # lowest nonnegative index (or -1)
180 def _ignore_comments(self, block: bytes) -> bytes:
181 if self._comment_spans:
182 # Finish current comment
183 while block:
184 comment_end = self._find_comment_end(block)
185 if comment_end != -1:
186 # Comment ends in this block
187 # Delete tail of comment
188 block = block[comment_end + 1 :]
189 break
190 else:
191 # Comment spans whole block
192 # So read the next block, looking for the end
193 block = self._read_block()
195 # Search for any further comments
196 self._comment_spans = False
197 while True:
198 comment_start = block.find(b"#")
199 if comment_start == -1:
200 # No comment found
201 break
202 comment_end = self._find_comment_end(block, comment_start)
203 if comment_end != -1:
204 # Comment ends in this block
205 # Delete comment
206 block = block[:comment_start] + block[comment_end + 1 :]
207 else:
208 # Comment continues to next block(s)
209 block = block[:comment_start]
210 self._comment_spans = True
211 break
212 return block
214 def _decode_bitonal(self) -> bytearray:
215 """
216 This is a separate method because in the plain PBM format, all data tokens are
217 exactly one byte, so the inter-token whitespace is optional.
218 """
219 data = bytearray()
220 total_bytes = self.state.xsize * self.state.ysize
222 while len(data) != total_bytes:
223 block = self._read_block() # read next block
224 if not block:
225 # eof
226 break
228 block = self._ignore_comments(block)
230 tokens = b"".join(block.split())
231 for token in tokens:
232 if token not in (48, 49):
233 msg = b"Invalid token for this mode: %s" % bytes([token])
234 raise ValueError(msg)
235 data = (data + tokens)[:total_bytes]
236 invert = bytes.maketrans(b"01", b"\xff\x00")
237 return data.translate(invert)
239 def _decode_blocks(self, maxval: int) -> bytearray:
240 data = bytearray()
241 max_len = 10
242 out_byte_count = 4 if self.mode == "I" else 1
243 out_max = 65535 if self.mode == "I" else 255
244 bands = Image.getmodebands(self.mode)
245 total_bytes = self.state.xsize * self.state.ysize * bands * out_byte_count
247 half_token = b""
248 while len(data) != total_bytes:
249 block = self._read_block() # read next block
250 if not block:
251 if half_token:
252 block = b" " # flush half_token
253 else:
254 # eof
255 break
257 block = self._ignore_comments(block)
259 if half_token:
260 block = half_token + block # stitch half_token to new block
261 half_token = b""
263 tokens = block.split()
265 if block and not block[-1:].isspace(): # block might split token
266 half_token = tokens.pop() # save half token for later
267 if len(half_token) > max_len: # prevent buildup of half_token
268 msg = (
269 b"Token too long found in data: %s" % half_token[: max_len + 1]
270 )
271 raise ValueError(msg)
273 for token in tokens:
274 if len(token) > max_len:
275 msg = b"Token too long found in data: %s" % token[: max_len + 1]
276 raise ValueError(msg)
277 value = int(token)
278 if value < 0:
279 msg_str = f"Channel value is negative: {value}"
280 raise ValueError(msg_str)
281 if value > maxval:
282 msg_str = f"Channel value too large for this mode: {value}"
283 raise ValueError(msg_str)
284 value = round(value / maxval * out_max)
285 data += o32(value) if self.mode == "I" else o8(value)
286 if len(data) == total_bytes: # finished!
287 break
288 return data
290 def decode(self, buffer: Image.DecoderInput) -> tuple[int, int]:
291 self._comment_spans = False
292 if self.mode == "1":
293 data = self._decode_bitonal()
294 rawmode = "1;8"
295 else:
296 maxval = self.args[-1]
297 data = self._decode_blocks(maxval)
298 rawmode = "I;32" if self.mode == "I" else self.mode
299 self.set_as_raw(bytes(data), rawmode)
300 return -1, 0
303class PpmDecoder(ImageFile.PyDecoder):
304 _pulls_fd = True
306 def decode(self, buffer: Image.DecoderInput) -> tuple[int, int]:
307 assert self.fd is not None
309 data = bytearray()
310 maxval = self.args[-1]
311 in_byte_count = 1 if maxval < 256 else 2
312 out_byte_count = 4 if self.mode == "I" else 1
313 out_max = 65535 if self.mode == "I" else 255
314 bands = Image.getmodebands(self.mode)
315 dest_length = self.state.xsize * self.state.ysize * bands * out_byte_count
316 while len(data) < dest_length:
317 pixels = self.fd.read(in_byte_count * bands)
318 if len(pixels) < in_byte_count * bands:
319 # eof
320 break
321 for b in range(bands):
322 value = (
323 pixels[b] if in_byte_count == 1 else i16(pixels, b * in_byte_count)
324 )
325 value = min(out_max, round(value / maxval * out_max))
326 data += o32(value) if self.mode == "I" else o8(value)
327 rawmode = "I;32" if self.mode == "I" else self.mode
328 self.set_as_raw(bytes(data), rawmode)
329 return -1, 0
332#
333# --------------------------------------------------------------------
336def _save(im: Image.Image, fp: IO[bytes], filename: str | bytes) -> None:
337 if im.mode == "1":
338 rawmode, head = "1;I", b"P4"
339 elif im.mode == "L":
340 rawmode, head = "L", b"P5"
341 elif im.mode in ("I", "I;16"):
342 rawmode, head = "I;16B", b"P5"
343 elif im.mode in ("RGB", "RGBA"):
344 rawmode, head = "RGB", b"P6"
345 elif im.mode == "F":
346 rawmode, head = "F;32F", b"Pf"
347 else:
348 msg = f"cannot write mode {im.mode} as PPM"
349 raise OSError(msg)
350 fp.write(head + b"\n%d %d\n" % im.size)
351 if head == b"P6":
352 fp.write(b"255\n")
353 elif head == b"P5":
354 if rawmode == "L":
355 fp.write(b"255\n")
356 else:
357 fp.write(b"65535\n")
358 elif head == b"Pf":
359 fp.write(b"-1.0\n")
360 row_order = -1 if im.mode == "F" else 1
361 ImageFile._save(im, fp, [ImageFile._Tile("raw", args=(rawmode, 0, row_order))])
364#
365# --------------------------------------------------------------------
368Image.register_open(PpmImageFile.format, PpmImageFile, _accept)
369Image.register_save(PpmImageFile.format, _save)
371Image.register_decoder("ppm", PpmDecoder)
372Image.register_decoder("ppm_plain", PpmPlainDecoder)
374Image.register_extensions(PpmImageFile.format, [".pbm", ".pgm", ".ppm", ".pnm", ".pfm"])
376Image.register_mime(PpmImageFile.format, "image/x-portable-anymap")