reformat with black

src/img2pdf.py

@@ -22,7 +22,17 @@ import sys
 import os
 import zlib
 import argparse
-from PIL import Image, TiffImagePlugin
+from PIL import Image, TiffImagePlugin, GifImagePlugin
+
+if hasattr(GifImagePlugin, "LoadingStrategy"):
+    # Pillow 9.0.0 started emitting all frames but the first as RGB instead of
+    # P to make sure that more than 256 colors can be represented. But palette
+    # images compress far better than RGB images in PDF so we instruct Pillow
+    # to only emit RGB frames if the palette differs and return P otherwise.
+    # This works since Pillow 9.1.0.
+    GifImagePlugin.LOADING_STRATEGY = (
+        GifImagePlugin.LoadingStrategy.RGB_AFTER_DIFFERENT_PALETTE_ONLY
+    )
 
 # TiffImagePlugin.DEBUG = True
 from PIL.ExifTags import TAGS
@@ -91,7 +101,10 @@ ImageFormat = Enum("ImageFormat", "JPEG JPEG2000 CCITTGroup4 PNG GIF TIFF MPO ot
 
 PageMode = Enum("PageMode", "none outlines thumbs")
 
-PageLayout = Enum("PageLayout", "single onecolumn twocolumnright twocolumnleft twopageright twopageleft")
+PageLayout = Enum(
+    "PageLayout",
+    "single onecolumn twocolumnright twocolumnleft twopageright twopageleft",
+)
 
 Magnification = Enum("Magnification", "fit fith fitbh")
 
@@ -389,6 +402,28 @@ class ExifOrientationError(Exception):
     pass
 
 
+# temporary change the attribute of an object using a context manager
+class temp_attr:
+    def __init__(self, obj, field, value):
+        self.obj = obj
+        self.field = field
+        self.value = value
+
+    def __enter__(self):
+        self.exists = False
+        if hasattr(self.obj, self.field):
+            self.exists = True
+            self.old_value = getattr(self.obj, self.field)
+        print(f"setting {self.obj}.{self.field} = {self.value}")
+        setattr(self.obj, self.field, self.value)
+
+    def __exit__(self, exctype, excinst, exctb):
+        if self.exists:
+            setattr(self.obj, self.field, self.old_value)
+        else:
+            delattr(self.obj, self.field)
+
+
 # without pdfrw this function is a no-op
 def my_convert_load(string):
     return string
@@ -1106,8 +1141,16 @@ class pdfdoc(object):
                 [initial_page, PdfName.XYZ, NullObject, NullObject, 0]
             )
 
-        # the /OpenAction array must contain the page as an indirect object
+        # The /OpenAction array must contain the page as an indirect object.
+        # This changed some time after 4.2.0 and on or before 5.0.0 and current
+        # versions require to use .obj or otherwise we get:
+        #   TypeError: Can't convert ObjectHelper (or subclass) to Object
+        #   implicitly. Use .obj to get access the underlying object.
+        # See https://github.com/pikepdf/pikepdf/issues/313 for details.
         if self.engine == Engine.pikepdf:
+            if isinstance(initial_page, pikepdf.Page):
+                initial_page = self.writer.make_indirect(initial_page.obj)
+            else:
                 initial_page = self.writer.make_indirect(initial_page)
 
         if self.magnification == Magnification.fit:
@@ -1410,27 +1453,29 @@ def transcode_monochrome(imgdata):
     # into putting everything into a single strip. Thanks to Andrew Murray for
     # the hack.
     #
-    # This can be dropped once this gets merged:
-    # https://github.com/python-pillow/Pillow/pull/5744
+    # Since version 8.4.0 Pillow allows us to modify the strip size explicitly
+    tmp_strip_size = (imgdata.size[0] + 7) // 8 * imgdata.size[1]
+    if hasattr(TiffImagePlugin, "STRIP_SIZE"):
+        # we are using Pillow 8.4.0 or later
+        with temp_attr(TiffImagePlugin, "STRIP_SIZE", tmp_strip_size):
+            im.save(newimgio, format="TIFF", compression="group4")
+    else:
+        # only needed for Pillow 8.3.x but works for versions before that as
+        # well
         pillow__getitem__ = TiffImagePlugin.ImageFileDirectory_v2.__getitem__
 
         def __getitem__(self, tag):
             overrides = {
                 TiffImagePlugin.ROWSPERSTRIP: imgdata.size[1],
-            TiffImagePlugin.STRIPBYTECOUNTS: [
-                (imgdata.size[0] + 7) // 8 * imgdata.size[1]
-            ],
+                TiffImagePlugin.STRIPBYTECOUNTS: [tmp_strip_size],
                 TiffImagePlugin.STRIPOFFSETS: [0],
             }
             return overrides.get(tag, pillow__getitem__(self, tag))
 
-    # use try/finally to make sure that __getitem__ is reset even if save()
-    # raises an exception
-    try:
-        TiffImagePlugin.ImageFileDirectory_v2.__getitem__ = __getitem__
+        with temp_attr(
+            TiffImagePlugin.ImageFileDirectory_v2, "__getitem__", __getitem__
+        ):
             im.save(newimgio, format="TIFF", compression="group4")
-    finally:
-        TiffImagePlugin.ImageFileDirectory_v2.__getitem__ = pillow__getitem__
 
     # Open new image in memory
     newimgio.seek(0)