Skip to content

Do not modify previous frame when calculating delta in PNG#6683

Merged
hugovk merged 1 commit intopython-pillow:mainfrom
radarhere:apng
Oct 24, 2022
Merged

Do not modify previous frame when calculating delta in PNG#6683
hugovk merged 1 commit intopython-pillow:mainfrom
radarhere:apng

Conversation

@radarhere
Copy link
Copy Markdown
Member

@radarhere radarhere commented Oct 24, 2022

Helps the original code in #6672

When iterating through frames to save a PNG, the following code

Pillow/src/PIL/PngImagePlugin.py

Lines 1130 to 1138 in c924fd8

if prev_disposal == Disposal.OP_BACKGROUND:
base_im = previous["im"]
dispose = Image.core.fill("RGBA", im.size, (0, 0, 0, 0))
bbox = previous["bbox"]
if bbox:
dispose = dispose.crop(bbox)
else:
bbox = (0, 0) + im.size
base_im.paste(dispose, bbox)

actually changing the previous frame with the paste operation.

This PR fixes that by making base_im a copy() instead.

@radarhere radarhere mentioned this pull request Oct 24, 2022
Closed
@hugovk hugovk merged commit a77eb67 into python-pillow:main Oct 24, 2022
@radarhere radarhere deleted the apng branch October 24, 2022 21:18
@sync-by-unito sync-by-unito bot mentioned this pull request Aug 28, 2023
Closed
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Reviewers

No reviews

Assignees

No one assigned

Labels

None yet

Projects

None yet

Milestone

No milestone

Development

Successfully merging this pull request may close these issues.

2 participants

@radarhere @hugovk