Bug 18702

Summary:	Some png images do not display correctly any more ("IDAT: invalid distance too far back" or "Decompression error in IDAT")
Product:	Mageia	Reporter:	Juergen Harms <juergen.harms>
Component:	RPM Packages	Assignee:	Funda Wang <fundawang>
Status:	RESOLVED FIXED	QA Contact:
Severity:	normal
Priority:	Normal	CC:	doc-bugs, marja11
Version:	Cauldron
Target Milestone:	---
Hardware:	All
OS:	Linux
Whiteboard:	MGA5TOO
Source RPM:	libpng-1.6.22-1.mga6.src.rpm	CVE:
Status comment:
Attachments:	Old png image file that fails to display on cauldron xcf file created with gimp, input = old png file new png file, exported by gimp on cauldron, input = xcf file

Description Juergen Harms 2016-06-13 23:16:11 CEST

Description of problem:

Several png images (e.g. 4 out of a set of 15) do not display any more (correctly displayed until recently) on a fully updated cauldron system (as of 13.6.2016 and using lib64png16_16-1.6.22):
- as images in a browser home page - now displayed by Firefox as blank,
- when opened with Gimp - gimp displays the png file as some clobbered nonsense
- dito with Gwenview

Similar problem in a fully updated Mageia-5 system. But the icons display correctly if I use the Mageia-5 system on my laptop that has not yet been updated and still uses lib64png16_16-1.6.20.

As a workaround, the png image files can be "fixed" and than display correctly on cauldron by the following sequence of actions:
1. open the png image with Gimp on a system that uses lib64png16_16-1.6.20,
2. and than create a corresponding xcf file,
3. open that xcf file with Gimp on the system that uses lib64png16_16-1.6.22 (cauldron) (updated libpng)
4. export the image as a new png image.

This newly created png file displays correctly on all systems which seems to indicate that the images themselves are OK, and that the problem appears to be an inconsistency in the handling of the png files by between the old and the new png library.

Joining 3 attachments:
- aonLogo_old.png ... old image file that does not display correctly on cauldron
- aonLogo.xcf ... image file created from aonLogo.old (using lib64png16_16-1.6.20)
- aonLogo_new.png ... image file exported by gimp using lib64png-1.6.22

Version-Release number of selected component (if applicable):

How reproducible:
100%

Steps to Reproduce:
1.
2.
3.

Comment 1 Juergen Harms 2016-06-13 23:19:08 CEST

Created attachment 7988 [details]
Old png image file that fails to display on cauldron

Comment 2 Juergen Harms 2016-06-13 23:20:04 CEST

Created attachment 7989 [details]
xcf file created with gimp, input = old png file

Comment 3 Juergen Harms 2016-06-13 23:21:25 CEST

Created attachment 7990 [details]
new png file, exported by gimp on cauldron, input = xcf file

Comment 4 Marja Van Waes 2016-06-15 10:27:31 CEST

Confirming the problem, attachment 7988 [details] gives an error here, when trying to view it with Ristretto:

    Fatal error reading png image file: Decompression error in IDAT

When trying to view it with the Gimp started from a konsole, I get:

** (file-png:11546): WARNING **: Error loading PNG file: IDAT: invalid distance too far back

and Gwenview started from konsole gives a similar message:

   libpng error: IDAT: invalid distance too far back


Assigning to libpng maintainer

(CC'ing docteam, even if five randomly checked png files in our documentation weren't affected, in case displaying some others of the very many png files in our manuals /is/ affected)

CC: (none) => doc-bugs, marja11
Assignee: bugsquad => fundawang
Summary: Some png images do not display correctly any more => Some png images do not display correctly any more ("IDAT: invalid distance too far back" or "Decompression error in IDAT")
Whiteboard: (none) => MGA5TOO

Comment 5 sturmvogel 2022-06-05 08:19:12 CEST

6 years and many libpng versions later this problem seems fixed. png's open just fine.

Closing as FIXED.

Status: NEW => RESOLVED
Resolution: (none) => FIXED