Bug 197218

Summary:	MetaDataEdit corrupts CRC information in PNGs
Product:	[Applications] digikam	Reporter:	Michael G. Hansen <mike>
Component:	Plugin-Generic-MetadataEdit	Assignee:	Digikam Developers <digikam-bugs-null>
Status:	RESOLVED FIXED
Severity:	normal
Priority:	NOR
Version First Reported In:	unspecified
Target Milestone:	---
Platform:	Debian testing
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:	0.4.0
Sentry Crash Report:
Attachments:	Test-png file without errors, created with inkscape test-1-okay.png modified using MetaDataEdit->Edit Exif, CRC errors

Description Michael G. Hansen 2009-06-20 02:41:46 UTC

Version:           0.3 (using KDE 4.2.4)
OS:                Linux
Installed from:    Debian testing/unstable Packages

Performing any of the operations that the MetaDataEdit-plugin provides on PNG images leads to corruption of the CRCs in the PNG, as shown by the following libpng warning messages:
libpng warning: zTXt: CRC error
libpng warning: iTXt: CRC error

These are printed to the console by most programs (gimp, kuickshow of kde3, digikam) that open these modified PNGs. All image-data seems to be intact, however (verified using compare of ImageMagick). I only stumbled upon the problem because "pngcrush" aborts on any libpng warnings.

Comment 1 Michael G. Hansen 2009-06-20 03:44:48 UTC

Created attachment 34665 [details]
Test-png file without errors, created with inkscape

Comment 2 Michael G. Hansen 2009-06-20 03:46:33 UTC

Created attachment 34666 [details]
test-1-okay.png modified using MetaDataEdit->Edit Exif, CRC errors

test-1-okay.png modified using MetaDataEdit->Edit Exif, set Name to Test.
This file shows CRC errors when opened in kuickshow:

libpng warning: zTXt: CRC error
libpng warning: zTXt: CRC error
libpng warning: iTXt: CRC error

Comment 3 caulier.gilles 2009-06-20 08:17:20 UTC

This is not the plugin, but Exiv2 library. this problem is fixed with current Exiv2 code from svn (next 0.18.2).

Gilles Caulier