id card generator

1 files changed, 108 insertions, 0 deletions

diff --git a/env/lib/python3.10/site-packages/pikepdf/jbig2.py b/env/lib/python3.10/site-packages/pikepdf/jbig2.py
new file mode 100644
index 0000000..28c596b
--- /dev/null
+++ b/env/lib/python3.10/site-packages/pikepdf/jbig2.py
@@ -0,0 +1,108 @@
+# SPDX-FileCopyrightText: 2022 James R. Barlow
+# SPDX-License-Identifier: MPL-2.0
+
+"""Integrate JBIG2 image decoding.
+
+Requires third-party JBIG2 decoder in the form of an external program, like
+jbig2dec.
+"""
+
+from __future__ import annotations
+
+import os
+from abc import ABC, abstractmethod
+from pathlib import Path
+from subprocess import DEVNULL, PIPE, CalledProcessError, run
+from tempfile import TemporaryDirectory
+
+from packaging.version import Version
+from PIL import Image
+
+from pikepdf._exceptions import DependencyError
+
+
+def _extract_jbig2_bytes(jbig2: bytes, jbig2_globals: bytes) -> bytes:
+    with TemporaryDirectory(prefix='pikepdf-', suffix='.jbig2') as tmpdir:
+        image_path = Path(tmpdir) / "image"
+        global_path = Path(tmpdir) / "global"
+        output_path = Path(tmpdir) / "outfile"
+
+        args = [
+            "jbig2dec",
+            "--embedded",
+            "--format",
+            "png",
+            "--output",
+            os.fspath(output_path),
+        ]
+
+        # Get the raw stream, because we can't decode im_obj - that is why we are here
+        # (Strictly speaking we should remove any non-JBIG2 filters if double encoded)
+        image_path.write_bytes(jbig2)
+
+        if len(jbig2_globals) > 0:
+            global_path.write_bytes(jbig2_globals)
+            args.append(os.fspath(global_path))
+
+        args.append(os.fspath(image_path))
+
+        run(args, stdout=DEVNULL, check=True)
+        with Image.open(output_path) as im:
+            return im.tobytes()
+
+
+class JBIG2DecoderInterface(ABC):
+    """pikepdf's C++ expects this Python interface to be available for JBIG2."""
+
+    @abstractmethod
+    def check_available(self) -> None:
+        """Check if decoder is available. Throws DependencyError if not."""
+
+    @abstractmethod
+    def decode_jbig2(self, jbig2: bytes, jbig2_globals: bytes) -> bytes:
+        """Decode JBIG2 from jbig2 and globals, returning decoded bytes."""
+
+    def available(self) -> bool:
+        """Return True if decoder is available."""
+        try:
+            self.check_available()
+        except DependencyError:
+            return False
+        else:
+            return True
+
+
+class JBIG2Decoder(JBIG2DecoderInterface):
+    """JBIG2 decoder implementation."""
+
+    def check_available(self) -> None:
+        """Check if jbig2dec is installed and usable."""
+        version = self._version()
+        if version < Version('0.15'):
+            raise DependencyError("jbig2dec is too old (older than version 0.15)")
+
+    def decode_jbig2(self, jbig2: bytes, jbig2_globals: bytes) -> bytes:
+        """Decode JBIG2 from binary data, returning decode bytes."""
+        return _extract_jbig2_bytes(jbig2, jbig2_globals)
+
+    def _version(self) -> Version:
+        try:
+            proc = run(
+                ['jbig2dec', '--version'], stdout=PIPE, check=True, encoding='ascii'
+            )
+        except (CalledProcessError, FileNotFoundError) as e:
+            raise DependencyError("jbig2dec - not installed or not found") from e
+        else:
+            result = proc.stdout
+            version_str = result.replace(
+                'jbig2dec', ''
+            ).strip()  # returns "jbig2dec 0.xx"
+            return Version(version_str)
+
+
+_jbig2_decoder = JBIG2Decoder()
+
+
+def get_decoder() -> JBIG2DecoderInterface:
+    """Return an instance of a JBIG2 decoder."""
+    return _jbig2_decoder