195 lines
5.4 KiB
Python
195 lines
5.4 KiB
Python
#
|
|
# The Python Imaging Library.
|
|
#
|
|
# MSP file handling
|
|
#
|
|
# This is the format used by the Paint program in Windows 1 and 2.
|
|
#
|
|
# History:
|
|
# 95-09-05 fl Created
|
|
# 97-01-03 fl Read/write MSP images
|
|
# 17-02-21 es Fixed RLE interpretation
|
|
#
|
|
# Copyright (c) Secret Labs AB 1997.
|
|
# Copyright (c) Fredrik Lundh 1995-97.
|
|
# Copyright (c) Eric Soroos 2017.
|
|
#
|
|
# See the README file for information on usage and redistribution.
|
|
#
|
|
# More info on this format: https://archive.org/details/gg243631
|
|
# Page 313:
|
|
# Figure 205. Windows Paint Version 1: "DanM" Format
|
|
# Figure 206. Windows Paint Version 2: "LinS" Format. Used in Windows V2.03
|
|
#
|
|
# See also: http://www.fileformat.info/format/mspaint/egff.htm
|
|
|
|
import io
|
|
import struct
|
|
|
|
from . import Image, ImageFile
|
|
from ._binary import i16le as i16
|
|
from ._binary import o16le as o16
|
|
|
|
#
|
|
# read MSP files
|
|
|
|
|
|
def _accept(prefix):
|
|
return prefix[:4] in [b"DanM", b"LinS"]
|
|
|
|
|
|
##
|
|
# Image plugin for Windows MSP images. This plugin supports both
|
|
# uncompressed (Windows 1.0).
|
|
|
|
|
|
class MspImageFile(ImageFile.ImageFile):
|
|
|
|
format = "MSP"
|
|
format_description = "Windows Paint"
|
|
|
|
def _open(self):
|
|
|
|
# Header
|
|
s = self.fp.read(32)
|
|
if not _accept(s):
|
|
raise SyntaxError("not an MSP file")
|
|
|
|
# Header checksum
|
|
checksum = 0
|
|
for i in range(0, 32, 2):
|
|
checksum = checksum ^ i16(s, i)
|
|
if checksum != 0:
|
|
raise SyntaxError("bad MSP checksum")
|
|
|
|
self.mode = "1"
|
|
self._size = i16(s, 4), i16(s, 6)
|
|
|
|
if s[:4] == b"DanM":
|
|
self.tile = [("raw", (0, 0) + self.size, 32, ("1", 0, 1))]
|
|
else:
|
|
self.tile = [("MSP", (0, 0) + self.size, 32, None)]
|
|
|
|
|
|
class MspDecoder(ImageFile.PyDecoder):
|
|
# The algo for the MSP decoder is from
|
|
# http://www.fileformat.info/format/mspaint/egff.htm
|
|
# cc-by-attribution -- That page references is taken from the
|
|
# Encyclopedia of Graphics File Formats and is licensed by
|
|
# O'Reilly under the Creative Common/Attribution license
|
|
#
|
|
# For RLE encoded files, the 32byte header is followed by a scan
|
|
# line map, encoded as one 16bit word of encoded byte length per
|
|
# line.
|
|
#
|
|
# NOTE: the encoded length of the line can be 0. This was not
|
|
# handled in the previous version of this encoder, and there's no
|
|
# mention of how to handle it in the documentation. From the few
|
|
# examples I've seen, I've assumed that it is a fill of the
|
|
# background color, in this case, white.
|
|
#
|
|
#
|
|
# Pseudocode of the decoder:
|
|
# Read a BYTE value as the RunType
|
|
# If the RunType value is zero
|
|
# Read next byte as the RunCount
|
|
# Read the next byte as the RunValue
|
|
# Write the RunValue byte RunCount times
|
|
# If the RunType value is non-zero
|
|
# Use this value as the RunCount
|
|
# Read and write the next RunCount bytes literally
|
|
#
|
|
# e.g.:
|
|
# 0x00 03 ff 05 00 01 02 03 04
|
|
# would yield the bytes:
|
|
# 0xff ff ff 00 01 02 03 04
|
|
#
|
|
# which are then interpreted as a bit packed mode '1' image
|
|
|
|
_pulls_fd = True
|
|
|
|
def decode(self, buffer):
|
|
|
|
img = io.BytesIO()
|
|
blank_line = bytearray((0xFF,) * ((self.state.xsize + 7) // 8))
|
|
try:
|
|
self.fd.seek(32)
|
|
rowmap = struct.unpack_from(
|
|
f"<{self.state.ysize}H", self.fd.read(self.state.ysize * 2)
|
|
)
|
|
except struct.error as e:
|
|
raise OSError("Truncated MSP file in row map") from e
|
|
|
|
for x, rowlen in enumerate(rowmap):
|
|
try:
|
|
if rowlen == 0:
|
|
img.write(blank_line)
|
|
continue
|
|
row = self.fd.read(rowlen)
|
|
if len(row) != rowlen:
|
|
raise OSError(
|
|
"Truncated MSP file, expected %d bytes on row %s", (rowlen, x)
|
|
)
|
|
idx = 0
|
|
while idx < rowlen:
|
|
runtype = row[idx]
|
|
idx += 1
|
|
if runtype == 0:
|
|
(runcount, runval) = struct.unpack_from("Bc", row, idx)
|
|
img.write(runval * runcount)
|
|
idx += 2
|
|
else:
|
|
runcount = runtype
|
|
img.write(row[idx : idx + runcount])
|
|
idx += runcount
|
|
|
|
except struct.error as e:
|
|
raise OSError(f"Corrupted MSP file in row {x}") from e
|
|
|
|
self.set_as_raw(img.getvalue(), ("1", 0, 1))
|
|
|
|
return 0, 0
|
|
|
|
|
|
Image.register_decoder("MSP", MspDecoder)
|
|
|
|
|
|
#
|
|
# write MSP files (uncompressed only)
|
|
|
|
|
|
def _save(im, fp, filename):
|
|
|
|
if im.mode != "1":
|
|
raise OSError(f"cannot write mode {im.mode} as MSP")
|
|
|
|
# create MSP header
|
|
header = [0] * 16
|
|
|
|
header[0], header[1] = i16(b"Da"), i16(b"nM") # version 1
|
|
header[2], header[3] = im.size
|
|
header[4], header[5] = 1, 1
|
|
header[6], header[7] = 1, 1
|
|
header[8], header[9] = im.size
|
|
|
|
checksum = 0
|
|
for h in header:
|
|
checksum = checksum ^ h
|
|
header[12] = checksum # FIXME: is this the right field?
|
|
|
|
# header
|
|
for h in header:
|
|
fp.write(o16(h))
|
|
|
|
# image body
|
|
ImageFile._save(im, fp, [("raw", (0, 0) + im.size, 32, ("1", 0, 1))])
|
|
|
|
|
|
#
|
|
# registry
|
|
|
|
Image.register_open(MspImageFile.format, MspImageFile, _accept)
|
|
Image.register_save(MspImageFile.format, _save)
|
|
|
|
Image.register_extension(MspImageFile.format, ".msp")
|