[Openicc] Extra metadata keys for review

[Richard Hughes]

As discussed with Kai-Uwe, I'm presenting a list of additional
metadata keys for review for the ICC metadata spec. I'm not
particularity attached to the names, although they have been used in
gnome-color-manager and dispcalgui for some time, so I'd prefer not
changing them if possible.

STANDARD_space		A standard space, where "srgb" -> sRGB; "adobe-rgb" ->
AdobeRGB; "prophoto-rgb" -> ProPhotoRGB
EDID_md5		The EDID MD5 checksum
CMF_product		The color management framework name that generated this
profile, e.g. "GNOME Color Manager"
CMF_binary		The color management framework binary that generated this
profile, e.g. "gcm-calibrate"
CMF_version		The color management framework version that generated
this profile, e.g. "3.1.1"
DATA_source		The data source of the profile, where: "edid" -> From a
display EDID blob; "calib" -> From a calibration; "standard" -> From a
standard, e.g. "sRGB"; "test" -> For testing, e.g. "BGR"
MAPPING_format		The format used for matching, e.g.
"ColorModel.OutputMode.OutputResolution"
MAPPING_qualifier	The qualifiers the profile should adopt by default,
e.g. "RGB.Plain.300dpi"
MAPPING_device_id	The device this profile should be paired with, e.g.
"cups-Photosmart-B109a-m"
ACCURACY_dE76_avg	The calibration delta-E average value
ACCURACY_dE76_max	The calibration delta-E maximum error value
ACCURACY_dE76_rms	The calibration delta-E RMS error value
MEASUREMENT_device	The device used to create the profile, e.g.
"colormunki" or "huey"
SCREEN_surface		The screen panel surface type, where: "matte" ->
Matte, textured surface "glossy" -> Glossy, shiny surface
SCREEN_brightness	The screen brightness as set during calibration as a
percentage, e.g. "50"
CONNECTION_type		The connection type of the video output, where:
"internal" -> Internal digital, e.g. LVDS; "vga" -> Analogue VGA;
"dvi" -> Digital DVI; "hdmi" -> Digital HDMI; "displayport" -> Digital
DisplayPort
GAMUT_volume		The volume of the gamut, (scaled to sRGB = 1.0)
expressed as a positive floating point value.
GAMUT_coverage($x)	The coverage of the gamut compared to a standard
gamut, given as $x. The values in $x can be any of the standard spaces
allowed in STANDARD_space for example "adobe-rgb". This is expressed
as a positive floating point value where 0.0 is none, and 1.0 is full
coverage.

Initial comments from Kai-Uwe and me were that:
 * STANDARD_space makes a ton of sense when you want to use the Adobe
supplied profile rather than the Clay profile, or the Facebook sRGB
rather than the official sRGB.
 * EDID_md5 is a no-brainer
 * CMF_ is a good idea, but Kai-Uwe didn't like the Color Management
Framework nomenclature prefix
 * DATA_source for when you've used a tool should "characterisation",
although it's longer and we have to decide on en_US or en_UK.
 * MAPPING_device_id probably only makes sense for colord, although I
guess Oyranos could do something with it too. (I'm okay not to propose
this key if that's an issue)

Comments welcome. Thanks

Richard