Added reading of JPEG2000 comments#6909
Merged
hugovk merged 1 commit intopython-pillow:mainfrom Mar 22, 2023
Merged
Conversation
8a9b598 to
f3cccbb
Compare
f3cccbb to
88c1066
Compare
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
#6903 adds writing of JPEG2000 comments, so I thought it would be helpful to also be able to read JPEG2000 comments.
Looking at image data, I saw that shortly after
_parse_jp2_header()had seeked forward in the file, there was "jp2c", signalling a "Contiguous codestream box". The next bytes were b"\xff\x4f\xff\x51", as Pillow checked for a few lines earlier before running_parse_codestream().So using
_parse_codestream()as a basis, this PR reads the type of the marker, the length, and the rest of the data in the marker, until reaching a "comment" marker, or breaking if the data ends, or if "start of tile" or "end of codestream" is reached first. See https://github.com/corkami/formats/blob/master/image/jpeg.md#jpeg-2000 for the marker types.I've added a test image, just saved with Pillow.