I can confirm that this annoying warning message also occurs with the
OpenSuse Factory distro. I first noticed that this was occuring with
PlayOnLinux 4.2.1-1.1 after updating my packages from OpenSuse 12.3 to
OpenSuse Factory (latest packages). I believe that the warning started
occuring with my update to Libpng16-16 (v 1.6.2-2.2
Research into Libpng's documented changes led me to :
to Libpng from version 1.5.x to 1.6.x can be found in section XII.
However, I will post the portion that I believe is relevant below for
Error detection in some chunks has improved; in particular the iCCP chunk
reader now does pretty complete validation of the basic format. Some bad
profiles that were previously accepted are now rejected, in particular the
very old broken Microsoft/HP sRGB profile.The PNG spec requirement that
only grayscale profiles may appear in images with color type 0 or 4 and
that even if the image only contains gray pixels, only RGB profiles may
appear in images with color type 2, 3, or 6, is now enforced. The sRGB
chunk is allowed to appear in images with any color type.
As you can see above, some of the bad profiles that were previously accepted are now being rejected.
there, I decided to gather information from one of the PNG images that
came with POL (as discussed earlier in this topic) that is causing the
warning. I started with the cmd.png image and looked into more
information about it by sending the commands below.
identify -verbose cmd.png
lot of information was displayed about the PNG file as expected, but at
the end of the ouput, the information that appeared relevant for
researching this problem has been shown below.
Version: ImageMagick 6.8.5-7 2013-06-17 Q8 http://www.imagemagick.org
identify: iCCP: known incorrect sRGB profile `cmd.png' @ warning/png.c/MagickPNGWarningHandler/1830.
From here, I decided to research the png.c file to gather more information which led me into too much code to look at.
I decided to look for newer changes that have been made since
ImageMagick 6.8.5-7 which was the version used for the PNG file (as
I came across discussions of corrupted color profiles regarding the JPEG format.
if an image went from JPEG to PNG, it could cause the color profile to
be corrupted. I'm assuming that this may be what has happened by
creation of the images for POL. I'm not sure if this could be the only
way that it could happen, but I believe that they have a fix for this
with newer versions of ImageMagick.
The change log discussing this issue can be found below.
The changes that I believe are relevant has been shown below for convenience.
- 2013-06-26 6.8.6-3
- Improve HCL to RGB roundtrip
- (reference http://www.imagemagick.org/discourse-server/viewtopic.php?f=3&t=22384).
- Prefer external log configuration file to built-in (reference
- Do not log in the IsLinkedListEmpty() method to prevent overflow
- Fix bug loading TGA image with 32-bit palette (reference
- Color profiles are no longer corrupted for the JPEG format
- Repair problem with -emboss / -equalize problem (reference
on another version they have also made changes to keep from writing
jpeg properties into a PNG output. The HCLpColorspace change also may be
- 2013-07-21 22.214.171.124
- Do not write "jpeg:" properties in a PNG output file (reference
- 2013-07-24 6.8.6-7
- Missing case for HCLpColorspace (reference http://www.imagemagick.org/discourse-server/viewtopic.php?f=3&t=23811).
My conclusion :
users using POL that have the warning message discussed, I recommend to
follow the instructions discussed earlier in this topic to correct the
images. However, there are also alternative ways to recreate the color
profile if you wish to research into those ways.
For myself, I corrected this issue by manually changing each image by using the command below.
convert filename.png -strip filename.png
the POL development team, please include images in the next version
that do not have this issue. Consider trying the latest ImageMagick
version for saving PNG files. I believe that the bug is originating from ImageMagick and not POL.
it is directly affecting POL users. I believe that it would be a
disadvantage for users to consider downgrading their version of Ligpng
to not see the warning. Reason being, the issues will still remain
within the PNG files, but will just be suppressed. Also, I believe that
users that have manually corrected the images for this warning
themselves will appreciate not having to correct them again with any
newer versions of POL.
Hope this helps.
Ändrat av Jayzon