use TiffImagePlugin.STRIP_SIZE for Pillow >= 8.4.0

This commit is contained in:
Johannes Schauer Marin Rodrigues 2022-04-07 21:58:23 +02:00
parent d9345ac767
commit c553e169a4
Signed by untrusted user: josch
GPG key ID: F2CBA5C78FBD83E1

View file

@ -399,6 +399,28 @@ class ExifOrientationError(Exception):
pass 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 # without pdfrw this function is a no-op
def my_convert_load(string): def my_convert_load(string):
return string return string
@ -1428,27 +1450,29 @@ def transcode_monochrome(imgdata):
# into putting everything into a single strip. Thanks to Andrew Murray for # into putting everything into a single strip. Thanks to Andrew Murray for
# the hack. # the hack.
# #
# This can be dropped once this gets merged: # Since version 8.4.0 Pillow allows us to modify the strip size explicitly
# https://github.com/python-pillow/Pillow/pull/5744 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__ pillow__getitem__ = TiffImagePlugin.ImageFileDirectory_v2.__getitem__
def __getitem__(self, tag): def __getitem__(self, tag):
overrides = { overrides = {
TiffImagePlugin.ROWSPERSTRIP: imgdata.size[1], TiffImagePlugin.ROWSPERSTRIP: imgdata.size[1],
TiffImagePlugin.STRIPBYTECOUNTS: [ TiffImagePlugin.STRIPBYTECOUNTS: [tmp_strip_size],
(imgdata.size[0] + 7) // 8 * imgdata.size[1]
],
TiffImagePlugin.STRIPOFFSETS: [0], TiffImagePlugin.STRIPOFFSETS: [0],
} }
return overrides.get(tag, pillow__getitem__(self, tag)) return overrides.get(tag, pillow__getitem__(self, tag))
# use try/finally to make sure that __getitem__ is reset even if save() with temp_attr(
# raises an exception TiffImagePlugin.ImageFileDirectory_v2, "__getitem__", __getitem__
try: ):
TiffImagePlugin.ImageFileDirectory_v2.__getitem__ = __getitem__
im.save(newimgio, format="TIFF", compression="group4") im.save(newimgio, format="TIFF", compression="group4")
finally:
TiffImagePlugin.ImageFileDirectory_v2.__getitem__ = pillow__getitem__
# Open new image in memory # Open new image in memory
newimgio.seek(0) newimgio.seek(0)