codekingpro/portable-devtools

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            self.bbox = im.info["wmf_bbox"]
49
50        def load(self, im: ImageFile.StubImageFile) -> Image.Image:
51            assert im.fp is not None
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 prefix.startswith((b"\xd7\xcd\xc6\x9a\x00\x00", b"\x01\x00\x00\x00"))
72
73
74##
75# Image plugin for Windows metafiles.
76
77
78class WmfStubImageFile(ImageFile.StubImageFile):
79    format = "WMF"
80    format_description = "Windows Metafile"
81
82    def _open(self) -> None:
83        # check placeable header
84        assert self.fp is not None
85        s = self.fp.read(44)
86
87        if s.startswith(b"\xd7\xcd\xc6\x9a\x00\x00"):
88            # placeable windows metafile
89
90            # get units per inch
91            inch = word(s, 14)
92            if inch == 0:
93                msg = "Invalid inch"
94                raise ValueError(msg)
95            self._inch: tuple[float, float] = inch, inch
96
97            # get bounding box
98            x0 = short(s, 6)
99            y0 = short(s, 8)
100            x1 = short(s, 10)
101            y1 = short(s, 12)
102
103            # normalize size to 72 dots per inch
104            self.info["dpi"] = 72
105            size = (
106                (x1 - x0) * self.info["dpi"] // inch,
107                (y1 - y0) * self.info["dpi"] // inch,
108            )
109
110            self.info["wmf_bbox"] = x0, y0, x1, y1
111
112            # sanity check (standard metafile header)
113            if s[22:26] != b"\x01\x00\t\x00":
114                msg = "Unsupported WMF file format"
115                raise SyntaxError(msg)
116
117        elif s.startswith(b"\x01\x00\x00\x00") and s[40:44] == b" EMF":
118            # enhanced metafile
119
120            # get bounding box
121            x0 = _long(s, 8)
122            y0 = _long(s, 12)
123            x1 = _long(s, 16)
124            y1 = _long(s, 20)
125
126            # get frame (in 0.01 millimeter units)
127            frame = _long(s, 24), _long(s, 28), _long(s, 32), _long(s, 36)
128
129            size = x1 - x0, y1 - y0
130
131            # calculate dots per inch from bbox and frame
132            xdpi = 2540.0 * (x1 - x0) / (frame[2] - frame[0])
133            ydpi = 2540.0 * (y1 - y0) / (frame[3] - frame[1])
134
135            self.info["wmf_bbox"] = x0, y0, x1, y1
136
137            if xdpi == ydpi:
138                self.info["dpi"] = xdpi
139            else:
140                self.info["dpi"] = xdpi, ydpi
141            self._inch = xdpi, ydpi
142
143        else:
144            msg = "Unsupported file format"
145            raise SyntaxError(msg)
146
147        self._mode = "RGB"
148        self._size = size
149
150    def _load(self) -> ImageFile.StubHandler | None:
151        return _handler
152
153    def load(
154        self, dpi: float | tuple[float, float] | None = None
155    ) -> Image.core.PixelAccess | None:
156        if dpi is not None:
157            self.info["dpi"] = dpi
158            x0, y0, x1, y1 = self.info["wmf_bbox"]
159            if not isinstance(dpi, tuple):
160                dpi = dpi, dpi
161            self._size = (
162                int((x1 - x0) * dpi[0] / self._inch[0]),
163                int((y1 - y0) * dpi[1] / self._inch[1]),
164            )
165        return super().load()
166
167
168def _save(im: Image.Image, fp: IO[bytes], filename: str | bytes) -> None:
169    if _handler is None or not hasattr(_handler, "save"):
170        msg = "WMF save handler not installed"
171        raise OSError(msg)
172    _handler.save(im, fp, filename)
173
174
175#
176# --------------------------------------------------------------------
177# Registry stuff
178
179
180Image.register_open(WmfStubImageFile.format, WmfStubImageFile, _accept)
181Image.register_save(WmfStubImageFile.format, _save)
182
183Image.register_extensions(WmfStubImageFile.format, [".wmf", ".emf"])
184