mirror of
https://github.com/python-pillow/Pillow.git
synced 2024-11-15 22:26:55 +03:00
343 lines
11 KiB
Python
343 lines
11 KiB
Python
#
|
|
# 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
|
|
from ._binary import i16be as i16
|
|
from ._binary import o8
|
|
from ._binary import o32le as o32
|
|
|
|
#
|
|
# --------------------------------------------------------------------
|
|
|
|
b_whitespace = b"\x20\x09\x0a\x0b\x0c\x0d"
|
|
|
|
MODES = {
|
|
# standard
|
|
b"P1": "1",
|
|
b"P2": "L",
|
|
b"P3": "RGB",
|
|
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"0123456y"
|
|
|
|
|
|
##
|
|
# Image plugin for PBM, PGM, and PPM images.
|
|
|
|
|
|
class PpmImageFile(ImageFile.ImageFile):
|
|
|
|
format = "PPM"
|
|
format_description = "Pbmplus image"
|
|
|
|
def _read_magic(self):
|
|
magic = b""
|
|
# read until whitespace or longest available magic number
|
|
for _ in range(6):
|
|
c = self.fp.read(1)
|
|
if not c or c in b_whitespace:
|
|
break
|
|
magic += c
|
|
return magic
|
|
|
|
def _read_token(self):
|
|
token = b""
|
|
while len(token) <= 10: # read until next whitespace or limit of 10 characters
|
|
c = self.fp.read(1)
|
|
if not c:
|
|
break
|
|
elif c in b_whitespace: # token ended
|
|
if not token:
|
|
# skip whitespace at start
|
|
continue
|
|
break
|
|
elif c == b"#":
|
|
# ignores rest of the line; stops at CR, LF or EOF
|
|
while self.fp.read(1) not in b"\r\n":
|
|
pass
|
|
continue
|
|
token += c
|
|
if not token:
|
|
# Token was not even 1 byte
|
|
raise ValueError("Reached EOF while reading header")
|
|
elif len(token) > 10:
|
|
raise ValueError(f"Token too long in file header: {token.decode()}")
|
|
return token
|
|
|
|
def _open(self):
|
|
magic_number = self._read_magic()
|
|
try:
|
|
mode = MODES[magic_number]
|
|
except KeyError:
|
|
raise SyntaxError("not a PPM file")
|
|
|
|
if magic_number in (b"P1", b"P4"):
|
|
self.custom_mimetype = "image/x-portable-bitmap"
|
|
elif magic_number in (b"P2", b"P5"):
|
|
self.custom_mimetype = "image/x-portable-graymap"
|
|
elif magic_number in (b"P3", b"P6"):
|
|
self.custom_mimetype = "image/x-portable-pixmap"
|
|
|
|
maxval = None
|
|
decoder_name = "raw"
|
|
if magic_number in (b"P1", b"P2", b"P3"):
|
|
decoder_name = "ppm_plain"
|
|
for ix in range(3):
|
|
token = int(self._read_token())
|
|
if ix == 0: # token is the x size
|
|
xsize = token
|
|
elif ix == 1: # token is the y size
|
|
ysize = token
|
|
if mode == "1":
|
|
self.mode = "1"
|
|
rawmode = "1;I"
|
|
break
|
|
else:
|
|
self.mode = rawmode = mode
|
|
elif ix == 2: # token is maxval
|
|
maxval = token
|
|
if not 0 < maxval < 65536:
|
|
raise ValueError(
|
|
"maxval must be greater than 0 and less than 65536"
|
|
)
|
|
if maxval > 255 and mode == "L":
|
|
self.mode = "I"
|
|
|
|
if decoder_name != "ppm_plain":
|
|
# If maxval matches a bit depth, use the raw decoder directly
|
|
if maxval == 65535 and mode == "L":
|
|
rawmode = "I;16B"
|
|
elif maxval != 255:
|
|
decoder_name = "ppm"
|
|
|
|
args = (rawmode, 0, 1) if decoder_name == "raw" else (rawmode, maxval)
|
|
self._size = xsize, ysize
|
|
self.tile = [(decoder_name, (0, 0, xsize, ysize), self.fp.tell(), args)]
|
|
|
|
|
|
#
|
|
# --------------------------------------------------------------------
|
|
|
|
|
|
class PpmPlainDecoder(ImageFile.PyDecoder):
|
|
_pulls_fd = True
|
|
|
|
def _read_block(self):
|
|
return self.fd.read(ImageFile.SAFEBLOCK)
|
|
|
|
def _find_comment_end(self, block, start=0):
|
|
a = block.find(b"\n", start)
|
|
b = block.find(b"\r", start)
|
|
return min(a, b) if a * b > 0 else max(a, b) # lowest nonnegative index (or -1)
|
|
|
|
def _ignore_comments(self, block):
|
|
if self._comment_spans:
|
|
# Finish current comment
|
|
while block:
|
|
comment_end = self._find_comment_end(block)
|
|
if comment_end != -1:
|
|
# Comment ends in this block
|
|
# Delete tail of comment
|
|
block = block[comment_end + 1 :]
|
|
break
|
|
else:
|
|
# Comment spans whole block
|
|
# So read the next block, looking for the end
|
|
block = self._read_block()
|
|
|
|
# Search for any further comments
|
|
self._comment_spans = False
|
|
while True:
|
|
comment_start = block.find(b"#")
|
|
if comment_start == -1:
|
|
# No comment found
|
|
break
|
|
comment_end = self._find_comment_end(block, comment_start)
|
|
if comment_end != -1:
|
|
# Comment ends in this block
|
|
# Delete comment
|
|
block = block[:comment_start] + block[comment_end + 1 :]
|
|
else:
|
|
# Comment continues to next block(s)
|
|
block = block[:comment_start]
|
|
self._comment_spans = True
|
|
break
|
|
return block
|
|
|
|
def _decode_bitonal(self):
|
|
"""
|
|
This is a separate method because in the plain PBM format, all data tokens are
|
|
exactly one byte, so the inter-token whitespace is optional.
|
|
"""
|
|
data = bytearray()
|
|
total_bytes = self.state.xsize * self.state.ysize
|
|
|
|
while len(data) != total_bytes:
|
|
block = self._read_block() # read next block
|
|
if not block:
|
|
# eof
|
|
break
|
|
|
|
block = self._ignore_comments(block)
|
|
|
|
tokens = b"".join(block.split())
|
|
for token in tokens:
|
|
if token not in (48, 49):
|
|
raise ValueError(f"Invalid token for this mode: {bytes([token])}")
|
|
data = (data + tokens)[:total_bytes]
|
|
invert = bytes.maketrans(b"01", b"\xFF\x00")
|
|
return data.translate(invert)
|
|
|
|
def _decode_blocks(self, maxval):
|
|
data = bytearray()
|
|
max_len = 10
|
|
out_byte_count = 4 if self.mode == "I" else 1
|
|
out_max = 65535 if self.mode == "I" else 255
|
|
bands = Image.getmodebands(self.mode)
|
|
total_bytes = self.state.xsize * self.state.ysize * bands * out_byte_count
|
|
|
|
half_token = False
|
|
while len(data) != total_bytes:
|
|
block = self._read_block() # read next block
|
|
if not block:
|
|
if half_token:
|
|
block = bytearray(b" ") # flush half_token
|
|
else:
|
|
# eof
|
|
break
|
|
|
|
block = self._ignore_comments(block)
|
|
|
|
if half_token:
|
|
block = half_token + block # stitch half_token to new block
|
|
|
|
tokens = block.split()
|
|
|
|
if block and not block[-1:].isspace(): # block might split token
|
|
half_token = tokens.pop() # save half token for later
|
|
if len(half_token) > max_len: # prevent buildup of half_token
|
|
raise ValueError(
|
|
f"Token too long found in data: {half_token[:max_len + 1]}"
|
|
)
|
|
|
|
for token in tokens:
|
|
if len(token) > max_len:
|
|
raise ValueError(
|
|
f"Token too long found in data: {token[:max_len + 1]}"
|
|
)
|
|
value = int(token)
|
|
if value > maxval:
|
|
raise ValueError(f"Channel value too large for this mode: {value}")
|
|
value = round(value / maxval * out_max)
|
|
data += o32(value) if self.mode == "I" else o8(value)
|
|
if len(data) == total_bytes: # finished!
|
|
break
|
|
return data
|
|
|
|
def decode(self, buffer):
|
|
self._comment_spans = False
|
|
if self.mode == "1":
|
|
data = self._decode_bitonal()
|
|
rawmode = "1;8"
|
|
else:
|
|
maxval = self.args[-1]
|
|
data = self._decode_blocks(maxval)
|
|
rawmode = "I;32" if self.mode == "I" else self.mode
|
|
self.set_as_raw(bytes(data), rawmode)
|
|
return -1, 0
|
|
|
|
|
|
class PpmDecoder(ImageFile.PyDecoder):
|
|
_pulls_fd = True
|
|
|
|
def decode(self, buffer):
|
|
data = bytearray()
|
|
maxval = self.args[-1]
|
|
in_byte_count = 1 if maxval < 256 else 2
|
|
out_byte_count = 4 if self.mode == "I" else 1
|
|
out_max = 65535 if self.mode == "I" else 255
|
|
bands = Image.getmodebands(self.mode)
|
|
while len(data) < self.state.xsize * self.state.ysize * bands * out_byte_count:
|
|
pixels = self.fd.read(in_byte_count * bands)
|
|
if len(pixels) < in_byte_count * bands:
|
|
# eof
|
|
break
|
|
for b in range(bands):
|
|
value = (
|
|
pixels[b] if in_byte_count == 1 else i16(pixels, b * in_byte_count)
|
|
)
|
|
value = min(out_max, round(value / maxval * out_max))
|
|
data += o32(value) if self.mode == "I" else o8(value)
|
|
rawmode = "I;32" if self.mode == "I" else self.mode
|
|
self.set_as_raw(bytes(data), rawmode)
|
|
return -1, 0
|
|
|
|
|
|
#
|
|
# --------------------------------------------------------------------
|
|
|
|
|
|
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":
|
|
rawmode, head = "I;16B", b"P5"
|
|
elif im.mode in ("RGB", "RGBA"):
|
|
rawmode, head = "RGB", b"P6"
|
|
else:
|
|
raise OSError(f"cannot write mode {im.mode} as PPM")
|
|
fp.write(head + b"\n%d %d\n" % im.size)
|
|
if head == b"P6":
|
|
fp.write(b"255\n")
|
|
elif head == b"P5":
|
|
if rawmode == "L":
|
|
fp.write(b"255\n")
|
|
else:
|
|
fp.write(b"65535\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_decoder("ppm", PpmDecoder)
|
|
Image.register_decoder("ppm_plain", PpmPlainDecoder)
|
|
|
|
Image.register_extensions(PpmImageFile.format, [".pbm", ".pgm", ".ppm", ".pnm"])
|
|
|
|
Image.register_mime(PpmImageFile.format, "image/x-portable-anymap")
|