Edgar,
I took a look at eciRGB_v2 and, indeed, found three tags 'pointing' to the
same 'offset':
tag 3:
sig 'rTRC'
type 'curv'
offset 520
size 1412
Curve:
No. elements = 700
tag 4:
sig 'gTRC'
type 'curv'
offset 520
size 1412
Curve:
No. elements = 700
tag 5:
sig 'bTRC'
type 'curv'
offset 520
size 1412
Curve:
No. elements = 700
In this case, I can see the logic since the 'curve' data must be the same
for all three channels but in the case of Argyll's tags, it is not the same
information in each of the last tags.
/ Roger
-----Original Message-----
From: argyllcms-bounce@xxxxxxxxxxxxx <argyllcms-bounce@xxxxxxxxxxxxx> On
Behalf Of Edgar Loser
Sent: Monday, January 27, 2020 6:35 AM
To: argyllcms@xxxxxxxxxxxxx
Subject: [argyllcms] Re: Sanity check -- excuse the newbie question
No, there is no need of an increasing offset.
The "offset" is a kind of pointer, pointing to the actual tag data.
For some tags the same data might be used.
e.g: trc for r,g,b in srgb or ecirgb profile:
http://www.color.org/srgbprofiles.xalter#v2
http://www.eci.org/_media/downloads/icc_profiles_from_eci/ecirgbv20.zip
Edgar
On 27.01.2020 05:25, graxx@xxxxxxxxxxxx wrote:
I made a monitor profile using Argyll.the offset value **increase** ?
When I dump the list of tags, I have the impression that there is an
error in the encoded offset of the last tags (14, 15, 16, 17): shouldnt
Here is a link to the profile:
https://1drv.ms/u/s!AkD78CVR1NBqktlq5D4dnpM4sp5fNA?e=xqt4D6
Here is the dump of the profile:
icc:
Header:
size = 2636 bytes
CMM = 'argl'
Version = 2.2.0
Device Class = Display
Color Space = RGB
Conn. Space = XYZ
Date, Time = 21 Jan 2020, 15:21:22
Platform = Microsoft
Flags = Not Embedded Profile, Use anywhere
Dev. Mnfctr. = 0x0
Dev. Model = 0x0
Dev. Attrbts = Reflective, Glossy, Positive, Color
Rndrng Intnt = Relative Colorimetric
Illuminant = 0.96420288, 1.00000000, 0.82490540 [Lab
100.000000, 0.000000, 0.000000]
Creator = 'argl'
tag 0:
sig 'desc'
type 'desc'
offset 348 bytes
size 134 bytes
TextDescription:
ASCII data, length 44 chars:
0x0000: NEC PA271W 20 patches aCMS 2020 01 21 15-21
No Unicode data
No ScriptCode data
tag 1:
sig 'cprt' 1668313716
type 'text'
offset 484
size 24
Text:
No. chars = 16
0x0000: Graxx Inc. 2020
tag 2:
sig 'dmnd'
type 'desc'
offset 508
size 94
TextDescription:
ASCII data, length 4 chars:
0x0000: NEC
No Unicode data
No ScriptCode data
tag 3:
sig 'dmdd'
type 'desc'
offset 604
size 97
TextDescription:
ASCII data, length 7 chars:
0x0000: PA271W
No Unicode data
No ScriptCode data
tag 4:
sig 'lumi'
type 'XYZ '
offset 704
size 20
XYZArray:
No. elements = 1
tag 5:
sig 'wtpt'
type 'XYZ '
offset 724 OK
size 20
XYZArray:
No. elements = 1
tag 6:
sig 'bkpt'
type 'XYZ '
offset 744
size 20
XYZArray:
No. elements = 1
tag 7:
sig 'clrt'
type 'clrt'
offset 764
size 126
ColorantTable:
No. colorants = 3
tag 8:
sig 'rXYZ'
type 'XYZ '
offset 892
size 20
XYZArray:
No. elements = 1
tag 9:
sig 'gXYZ'
type 'XYZ '
offset 912 OK
size 20
XYZArray:
No. elements = 1
tag 10:
sig 'bXYZ'
type 'XYZ '
offset 932 OK
size 20
XYZArray:
No. elements = 1
tag 11:
sig 'rTRC'
type 'curv'
offset 952
size 14
Curve:
Curve is gamma of 1.91406250
tag 12:
sig 'gTRC'
type 'curv'
offset 968
size 14
Curve:
Curve is gamma of 1.91015625
tag 13:
sig 'bTRC'
type 'curv'
offset 984 OK
size 14 OK
Curve:
Curve is gamma of 1.91406250
tag 14:
sig 'targ'
type 'text'
offset 1000
size 1590
Text:
No. chars = 1582
0x0000: CTI3 \015\012 \015\012DESCRIPTOR "Argyll Calibration
Target char
...
tag 15:
sig 'DevD' 1952543335
type 'text'
offset 1000 OK
size 1590 OK
Text:
No. chars = 1582
0x0000: CTI3 \015\012 \015\012DESCRIPTOR "Argyll Calibration
Target char
...
tag 16:
sig 'CIED' 1147500100
type 'text'
offset 1000
size 1590
Text:
No. chars = 1582
0x0000: CTI3 \015\012 \015\012DESCRIPTOR "Argyll Calibration
Target char
...
tag 17:
sig 'arts'
type 'sf32'
offset 2592
size 44
S15Fixed16Array:
No. elements = 9
/ Roger
