1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
|
//
// Little cms
// Copyright (C) 1998-2003 Marti Maria
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the Software
// is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO
// THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#include "lcms.h"
// This is a sample on how to build a profile for decoding ITU T.42/Fax JPEG
// streams. The profile has an additional ability in the input direction of
// gamut compress values between 85 < a < -85 and -75 < b < 125. This conforms
// the default range for ITU/T.42 -- See RFC 2301, section 6.2.3 for details
// L* = [0, 100]
// a* = [-85, 85]
// b* = [-75, 125]
// These functions does convert the encoding of ITUFAX to floating point
static
void ITU2Lab(WORD In[3], LPcmsCIELab Lab)
{
Lab -> L = (double) In[0] / 655.35;
Lab -> a = (double) 170.* (In[1] - 32768.) / 65535.;
Lab -> b = (double) 200.* (In[2] - 24576.) / 65535.;
}
static
void Lab2ITU(LPcmsCIELab Lab, WORD Out[3])
{
Out[0] = (WORD) floor((double) (Lab -> L / 100.)* 65535. + 0.5);
Out[1] = (WORD) floor((double) (Lab -> a / 170.)* 65535. + 32768. + 0.5);
Out[2] = (WORD) floor((double) (Lab -> b / 200.)* 65535. + 24576. + 0.5);
}
// These are the samplers-- They are passed as callbacks to cmsSample3DGrid()
// then, cmsSample3DGrid() will sweel whole Lab gamut calling these functions
// once for each node. In[] will contain the Lab PCS value to convert to ITUFAX
// on InputDirection, or the ITUFAX value to convert to Lab in OutputDirection
// You can change the number of sample points if desired, the algorithm will
// remain same. 33 points gives good accurancy, but you can reduce to 22 or less
// is space is critical
#define GRID_POINTS 33
static
int InputDirection(register WORD In[], register WORD Out[], register LPVOID Cargo)
{
cmsCIELab Lab;
cmsLabEncoded2Float(&Lab, In);
cmsClampLab(&Lab, 85, -85, 125, -75); // This function does the necessary gamut remapping
Lab2ITU(&Lab, Out);
return TRUE;
}
static
int OutputDirection(register WORD In[], register WORD Out[], register LPVOID Cargo)
{
cmsCIELab Lab;
ITU2Lab(In, &Lab);
cmsFloat2LabEncoded(Out, &Lab);
return TRUE;
}
// The main entry point. Just create a profile an populate it with required tags.
// note that cmsOpenProfileFromFile("itufax.icm", "w") will NOT delete the file
// if already exists. This is for obvious safety reasons.
int main(int argc, char *argv[])
{
LPLUT AToB0, BToA0;
cmsHPROFILE hProfile;
fprintf(stderr, "Creating itufax.icm...");
unlink("itufax.icm");
hProfile = cmsOpenProfileFromFile("itufax.icm", "w");
AToB0 = cmsAllocLUT();
BToA0 = cmsAllocLUT();
cmsAlloc3DGrid(AToB0, GRID_POINTS, 3, 3);
cmsAlloc3DGrid(BToA0, GRID_POINTS, 3, 3);
cmsSample3DGrid(AToB0, InputDirection, NULL, 0);
cmsSample3DGrid(BToA0, OutputDirection, NULL, 0);
cmsAddTag(hProfile, icSigAToB0Tag, AToB0);
cmsAddTag(hProfile, icSigBToA0Tag, BToA0);
cmsSetColorSpace(hProfile, icSigLabData);
cmsSetPCS(hProfile, icSigLabData);
cmsSetDeviceClass(hProfile, icSigColorSpaceClass);
cmsAddTag(hProfile, icSigProfileDescriptionTag, "ITU T.42/Fax JPEG CIEL*a*b*");
cmsAddTag(hProfile, icSigCopyrightTag, "No Copyright, use freely.");
cmsAddTag(hProfile, icSigDeviceMfgDescTag, "Little cms");
cmsAddTag(hProfile, icSigDeviceModelDescTag, "ITU T.42/Fax JPEG CIEL*a*b*");
cmsCloseProfile(hProfile);
cmsFreeLUT(AToB0);
cmsFreeLUT(BToA0);
fprintf(stderr, "Done.\n");
return 0;
}
|
