187 lines
5.1 KiB
Python
187 lines
5.1 KiB
Python
#
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# The Python Imaging Library
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# $Id$
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#
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# WMF stub codec
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#
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# history:
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# 1996-12-14 fl Created
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# 2004-02-22 fl Turned into a stub driver
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# 2004-02-23 fl Added EMF support
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#
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# Copyright (c) Secret Labs AB 1997-2004. All rights reserved.
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# Copyright (c) Fredrik Lundh 1996.
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#
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# See the README file for information on usage and redistribution.
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#
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# WMF/EMF reference documentation:
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# https://winprotocoldoc.blob.core.windows.net/productionwindowsarchives/MS-WMF/[MS-WMF].pdf
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# http://wvware.sourceforge.net/caolan/index.html
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# http://wvware.sourceforge.net/caolan/ora-wmf.html
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from __future__ import annotations
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from typing import IO
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from . import Image, ImageFile
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from ._binary import i16le as word
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from ._binary import si16le as short
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from ._binary import si32le as _long
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_handler = None
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def register_handler(handler: ImageFile.StubHandler | None) -> None:
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"""
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Install application-specific WMF image handler.
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:param handler: Handler object.
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"""
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global _handler
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_handler = handler
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if hasattr(Image.core, "drawwmf"):
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# install default handler (windows only)
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class WmfHandler(ImageFile.StubHandler):
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def open(self, im: ImageFile.StubImageFile) -> None:
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im._mode = "RGB"
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self.bbox = im.info["wmf_bbox"]
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def load(self, im: ImageFile.StubImageFile) -> Image.Image:
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im.fp.seek(0) # rewind
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return Image.frombytes(
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"RGB",
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im.size,
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Image.core.drawwmf(im.fp.read(), im.size, self.bbox),
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"raw",
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"BGR",
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(im.size[0] * 3 + 3) & -4,
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-1,
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)
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register_handler(WmfHandler())
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#
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# --------------------------------------------------------------------
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# Read WMF file
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def _accept(prefix: bytes) -> bool:
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return prefix.startswith((b"\xd7\xcd\xc6\x9a\x00\x00", b"\x01\x00\x00\x00"))
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##
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# Image plugin for Windows metafiles.
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class WmfStubImageFile(ImageFile.StubImageFile):
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format = "WMF"
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format_description = "Windows Metafile"
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def _open(self) -> None:
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# check placable header
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s = self.fp.read(44)
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if s.startswith(b"\xd7\xcd\xc6\x9a\x00\x00"):
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# placeable windows metafile
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# get units per inch
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inch = word(s, 14)
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if inch == 0:
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msg = "Invalid inch"
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raise ValueError(msg)
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self._inch: tuple[float, float] = inch, inch
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# get bounding box
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x0 = short(s, 6)
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y0 = short(s, 8)
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x1 = short(s, 10)
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y1 = short(s, 12)
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# normalize size to 72 dots per inch
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self.info["dpi"] = 72
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size = (
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(x1 - x0) * self.info["dpi"] // inch,
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(y1 - y0) * self.info["dpi"] // inch,
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)
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self.info["wmf_bbox"] = x0, y0, x1, y1
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# sanity check (standard metafile header)
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if s[22:26] != b"\x01\x00\t\x00":
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msg = "Unsupported WMF file format"
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raise SyntaxError(msg)
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elif s.startswith(b"\x01\x00\x00\x00") and s[40:44] == b" EMF":
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# enhanced metafile
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# get bounding box
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x0 = _long(s, 8)
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y0 = _long(s, 12)
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x1 = _long(s, 16)
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y1 = _long(s, 20)
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# get frame (in 0.01 millimeter units)
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frame = _long(s, 24), _long(s, 28), _long(s, 32), _long(s, 36)
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size = x1 - x0, y1 - y0
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# calculate dots per inch from bbox and frame
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xdpi = 2540.0 * (x1 - x0) / (frame[2] - frame[0])
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ydpi = 2540.0 * (y1 - y0) / (frame[3] - frame[1])
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self.info["wmf_bbox"] = x0, y0, x1, y1
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if xdpi == ydpi:
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self.info["dpi"] = xdpi
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else:
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self.info["dpi"] = xdpi, ydpi
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self._inch = xdpi, ydpi
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else:
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msg = "Unsupported file format"
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raise SyntaxError(msg)
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self._mode = "RGB"
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self._size = size
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loader = self._load()
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if loader:
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loader.open(self)
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def _load(self) -> ImageFile.StubHandler | None:
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return _handler
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def load(
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self, dpi: float | tuple[float, float] | None = None
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) -> Image.core.PixelAccess | None:
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if dpi is not None:
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self.info["dpi"] = dpi
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x0, y0, x1, y1 = self.info["wmf_bbox"]
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if not isinstance(dpi, tuple):
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dpi = dpi, dpi
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self._size = (
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int((x1 - x0) * dpi[0] / self._inch[0]),
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int((y1 - y0) * dpi[1] / self._inch[1]),
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)
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return super().load()
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def _save(im: Image.Image, fp: IO[bytes], filename: str | bytes) -> None:
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if _handler is None or not hasattr(_handler, "save"):
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msg = "WMF save handler not installed"
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raise OSError(msg)
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_handler.save(im, fp, filename)
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#
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# --------------------------------------------------------------------
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# Registry stuff
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Image.register_open(WmfStubImageFile.format, WmfStubImageFile, _accept)
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Image.register_save(WmfStubImageFile.format, _save)
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Image.register_extensions(WmfStubImageFile.format, [".wmf", ".emf"])
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