From c826b932c07522272eb1297a595c8c90726970db Mon Sep 17 00:00:00 2001 From: Andrew Murray Date: Tue, 19 Aug 2025 15:45:42 +1000 Subject: [PATCH] Document MAXBLOCK --- docs/reference/ImageFile.rst | 1 + src/PIL/ImageFile.py | 12 ++++++++++++ 2 files changed, 13 insertions(+) diff --git a/docs/reference/ImageFile.rst b/docs/reference/ImageFile.rst index 043559352..4c34ff812 100644 --- a/docs/reference/ImageFile.rst +++ b/docs/reference/ImageFile.rst @@ -74,5 +74,6 @@ Constants --------- .. autodata:: PIL.ImageFile.LOAD_TRUNCATED_IMAGES +.. autodata:: PIL.ImageFile.MAXBLOCK .. autodata:: PIL.ImageFile.ERRORS :annotation: diff --git a/src/PIL/ImageFile.py b/src/PIL/ImageFile.py index 27b27127e..e33b846d4 100644 --- a/src/PIL/ImageFile.py +++ b/src/PIL/ImageFile.py @@ -46,6 +46,18 @@ if TYPE_CHECKING: logger = logging.getLogger(__name__) MAXBLOCK = 65536 +""" +By default, Pillow processes image data in blocks. This helps to prevent excessive use +of resources. Codecs may disable this behaviour with ``_pulls_fd`` or ``_pushes_fd``. + +When reading an image, this is the number of bytes to read at once. + +When writing an image, this is the number of bytes to write at once. +If the image width times 4 is greater, then that will be used instead. +Plugins may also set a greater number. + +User code may set this to another number. +""" SAFEBLOCK = 1024 * 1024