On 01/24/2010 08:31 AM, Martin Nordholts wrote: > Omari Stephens wrote: >>> I had naively signed up for the "work on color management" job. That >>> said, do you happen to know where the sRGB thingie is added by default? >>> (if not, I can probably find it, but if you know offhand, I'm not >>> beyond laziness ;o) >> It was actually trivial to find. Right now, I'm just considering the >> consequences before I nuke that 4 lines of code. > > You are talking about > http://git.gnome.org/browse/gimp/tree/plug-ins/common/file-png.c#n1456 > right? > > Nuking those four lines is not enough, a way to embedd an sRGB profile > must also be added. Unfortunately, assagning an sRGB profile to an image > in current GIMP does not "stick" since sRGB is the default color space. > We need to change this. Changing this is likely to cause problems in > other parts of the color managed code which needs to be taken care of. Any licensing folks about? Debian's "icc-profiles" package ships an sRGB profile that has license [1]. The ICC itself also provides sRGB v2 and v4 ICC profiles for use with licenses [2] and [3], respectively. Can we ship one of these with GIMP? At the very least, the PNG spec calls for IEC 61966-2-1, which is one of the sRGB v2 profiles, though both the BPC-enabled and BPC-disabled versions seem to count as 61966-2-1. Also, from a practical standpoint, are there important situations where someone would want to tag a PNG as sRGB, but where simply applying the actual sRGB color profile wouldn't be a reasonable substitute to the sRGB PNG chunk? The PNG standard has this to say (from http://www.w3.org/TR/PNG/#11sRGB ): """ It is recommended that a PNG encoder that writes the sRGB chunk also write a gAMA chunk (and optionally a cHRM chunk) for compatibility with decoders that do not use the sRGB chunk. Only the following values shall be used. […] When the sRGB chunk is present, it is recommended that decoders that recognize it and are capable of colour management [ICC] ignore the gAMA and cHRM chunks and use the sRGB chunk instead. Decoders that recognize the sRGB chunk but are not capable of colour management [ICC] are recommended to ignore the gAMA and cHRM chunks, and use the values given above as if they had appeared in gAMA and cHRM chunks. It is recommended that the sRGB and iCCP chunks do not both appear in a PNG datastream. """ Here are the licenses: [1] HP sRGB license, from Debian's icc-profiles package: sRGB Profile Licensing Agreement: To anyone who acknowledges that the file "sRGB Color Space Profile.icm" is provided "AS IS" WITH NO EXPRESS OR IMPLIED WARRANTY: permission to use, copy and distribute this file for any purpose is hereby granted without fee, provided that the file is not changed including the HP copyright notice tag, and that the name of Hewlett-Packard Company not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission. Hewlett-Packard Company makes no representations about the suitability of this software for any purpose. [2] ICC sRGBv2 license, from http://www.color.org/srgbprofiles.xalter To anyone who acknowledges that the files "sRGB_IEC61966-2-1_no_black_scaling.icc" and "sRGB_IEC61966-2-1_black scaled.icc" are provided "AS IS" WITH NO EXPRESS OR IMPLIED WARRANTY, permission to use, copy and distribute these file for any purpose is hereby granted without fee, provided that the files are not changed including the ICC copyright notice tag, and that the name of ICC shall not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission. ICC makes no representations about the suitability of this software for any purpose. [3] ICC sRGBv4 license, from http://www.color.org/srgbprofiles.xalter To anyone who acknowledges that the file "sRGB_v4_ICC_preference.icc" is provided "AS IS" WITH NO EXPRESS OR IMPLIED WARRANTY, permission to use, copy and distribute this file for any purpose is hereby granted without fee, provided that the file is not changed including the ICC copyright notice tag, and that the name of ICC shall not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission. ICC makes no representations about the suitability of this software for any purpose. --xsdg _______________________________________________ Gimp-developer mailing list Gimp-developer@xxxxxxxxxxxxxxxxxxxxxx https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer
