1#
2# The Python Imaging Library
3# $Id$
4#
5# WMF stub codec
6#
7# history:
8# 1996-12-14 fl Created
9# 2004-02-22 fl Turned into a stub driver
10# 2004-02-23 fl Added EMF support
11#
12# Copyright (c) Secret Labs AB 1997-2004. All rights reserved.
13# Copyright (c) Fredrik Lundh 1996.
14#
15# See the README file for information on usage and redistribution.
16#
17# WMF/EMF reference documentation:
18# https://winprotocoldoc.blob.core.windows.net/productionwindowsarchives/MS-WMF/[MS-WMF].pdf
19# http://wvware.sourceforge.net/caolan/index.html
20# http://wvware.sourceforge.net/caolan/ora-wmf.html
21from __future__ import annotations
22
23from typing import IO
24
25from . import Image, ImageFile
26from ._binary import i16le as word
27from ._binary import si16le as short
28from ._binary import si32le as _long
29
30_handler = None
31
32
33def register_handler(handler: ImageFile.StubHandler | None) -> None:
34 """
35 Install application-specific WMF image handler.
36
37 :param handler: Handler object.
38 """
39 global _handler
40 _handler = handler
41
42
43if hasattr(Image.core, "drawwmf"):
44 # install default handler (windows only)
45
46 class WmfHandler(ImageFile.StubHandler):
47 def open(self, im: ImageFile.StubImageFile) -> None:
48 im._mode = "RGB"
49 self.bbox = im.info["wmf_bbox"]
50
51 def load(self, im: ImageFile.StubImageFile) -> Image.Image:
52 im.fp.seek(0) # rewind
53 return Image.frombytes(
54 "RGB",
55 im.size,
56 Image.core.drawwmf(im.fp.read(), im.size, self.bbox),
57 "raw",
58 "BGR",
59 (im.size[0] * 3 + 3) & -4,
60 -1,
61 )
62
63 register_handler(WmfHandler())
64
65#
66# --------------------------------------------------------------------
67# Read WMF file
68
69
70def _accept(prefix: bytes) -> bool:
71 return (
72 prefix[:6] == b"\xd7\xcd\xc6\x9a\x00\x00" or prefix[:4] == b"\x01\x00\x00\x00"
73 )
74
75
76##
77# Image plugin for Windows metafiles.
78
79
80class WmfStubImageFile(ImageFile.StubImageFile):
81 format = "WMF"
82 format_description = "Windows Metafile"
83
84 def _open(self) -> None:
85 self._inch = None
86
87 # check placable header
88 s = self.fp.read(80)
89
90 if s[:6] == b"\xd7\xcd\xc6\x9a\x00\x00":
91 # placeable windows metafile
92
93 # get units per inch
94 self._inch = word(s, 14)
95
96 # get bounding box
97 x0 = short(s, 6)
98 y0 = short(s, 8)
99 x1 = short(s, 10)
100 y1 = short(s, 12)
101
102 # normalize size to 72 dots per inch
103 self.info["dpi"] = 72
104 size = (
105 (x1 - x0) * self.info["dpi"] // self._inch,
106 (y1 - y0) * self.info["dpi"] // self._inch,
107 )
108
109 self.info["wmf_bbox"] = x0, y0, x1, y1
110
111 # sanity check (standard metafile header)
112 if s[22:26] != b"\x01\x00\t\x00":
113 msg = "Unsupported WMF file format"
114 raise SyntaxError(msg)
115
116 elif s[:4] == b"\x01\x00\x00\x00" and s[40:44] == b" EMF":
117 # enhanced metafile
118
119 # get bounding box
120 x0 = _long(s, 8)
121 y0 = _long(s, 12)
122 x1 = _long(s, 16)
123 y1 = _long(s, 20)
124
125 # get frame (in 0.01 millimeter units)
126 frame = _long(s, 24), _long(s, 28), _long(s, 32), _long(s, 36)
127
128 size = x1 - x0, y1 - y0
129
130 # calculate dots per inch from bbox and frame
131 xdpi = 2540.0 * (x1 - y0) / (frame[2] - frame[0])
132 ydpi = 2540.0 * (y1 - y0) / (frame[3] - frame[1])
133
134 self.info["wmf_bbox"] = x0, y0, x1, y1
135
136 if xdpi == ydpi:
137 self.info["dpi"] = xdpi
138 else:
139 self.info["dpi"] = xdpi, ydpi
140
141 else:
142 msg = "Unsupported file format"
143 raise SyntaxError(msg)
144
145 self._mode = "RGB"
146 self._size = size
147
148 loader = self._load()
149 if loader:
150 loader.open(self)
151
152 def _load(self) -> ImageFile.StubHandler | None:
153 return _handler
154
155 def load(self, dpi=None):
156 if dpi is not None and self._inch is not None:
157 self.info["dpi"] = dpi
158 x0, y0, x1, y1 = self.info["wmf_bbox"]
159 self._size = (
160 (x1 - x0) * self.info["dpi"] // self._inch,
161 (y1 - y0) * self.info["dpi"] // self._inch,
162 )
163 return super().load()
164
165
166def _save(im: Image.Image, fp: IO[bytes], filename: str | bytes) -> None:
167 if _handler is None or not hasattr(_handler, "save"):
168 msg = "WMF save handler not installed"
169 raise OSError(msg)
170 _handler.save(im, fp, filename)
171
172
173#
174# --------------------------------------------------------------------
175# Registry stuff
176
177
178Image.register_open(WmfStubImageFile.format, WmfStubImageFile, _accept)
179Image.register_save(WmfStubImageFile.format, _save)
180
181Image.register_extensions(WmfStubImageFile.format, [".wmf", ".emf"])