ColorChecker SG SVG generator

ColorCheckerSG.txt

		
LGOROWLENGTH 12
ORIGINATOR "ColorCheckerSG - November2014 edition and newer"
MANUFACTURER "X-Rite - http://www.xrite.com"

5/11/2015  # Time: 16:08			
"i1Pro 2 ; Serial number 1000691"			
"MeasurementCondition=M0	Filter=no"	

NUMBER_OF_FIELDS 4
BEGIN_DATA_FORMAT
Sample_NAME   Lab_L   Lab_a   Lab_b
END_DATA_FORMAT
NUMBER_OF_SETS 140
BEGIN_DATA
A1	96.71	-0.62	2.06
A2	8.05	0.17	-0.69
A3	49.76	0.11	0.72
A4	96.72	-0.63	2.06
A5	8.17	0.15	-0.65
A6	49.68	0.14	0.74
A7	96.60	-0.62	2.11
A8	7.99	0.21	-0.75
A9	49.67	0.15	0.73
A10	96.51	-0.63	2.11
B1	49.70	0.12	0.68
B2	33.02	52.00	-10.30
B3	61.40	27.14	-18.42
B4	30.54	50.39	-41.79
B5	49.56	-13.90	-49.65
B6	60.62	-29.91	-27.54
B7	20.13	-24.81	-7.50
B8	60.32	-40.29	-13.25
B9	19.62	1.77	11.99
B10	49.68	0.15	0.78
C1	8.13	0.15	-0.76
C2	19.65	20.42	-18.82
C3	41.70	18.90	-37.42
C4	20.25	0.26	-36.44
C5	60.13	-17.88	-32.08
C6	19.75	-17.79	-22.37
C7	60.43	-5.12	-32.79
C8	50.46	-47.90	-11.56
C9	60.53	-40.75	19.37
C10	8.09	0.19	-0.69
D1	96.79	-0.66	1.99
D2	84.00	-1.70	-8.37
D3	85.48	15.15	0.79
D4	84.56	-19.74	-1.13
D5	85.26	13.37	7.95
D6	84.38	-11.97	27.16
D7	62.35	29.94	36.89
D8	64.17	21.34	19.36
D9	50.48	-53.21	12.65
D10	96.57	-0.64	2.00
E1	49.79	0.13	0.66
E2	32.77	19.91	22.33
E3	62.28	37.56	68.87
E4	19.92	25.07	-61.05
E5	96.78	-0.66	2.01
E6	8.07	0.12	-0.93
E7	77.37	20.28	24.27
E8	74.01	29.00	25.80
E9	20.33	-23.98	7.20
E10	49.72	0.14	0.71
F1	8.09	0.19	-0.69
F2	63.88	20.34	19.93
F3	35.28	12.93	-51.17
F4	52.75	-44.12	38.68
F5	79.65	-0.08	0.62
F6	30.32	-0.10	0.22
F7	63.46	13.53	26.37
F8	64.44	14.31	17.63
F9	60.05	-44.00	7.27
F10	8.08	0.18	-0.78
G1	96.70	-0.66	1.97
G2	45.84	-3.74	-25.32
G3	47.60	53.66	22.15
G4	36.88	65.72	41.63
G5	65.22	-0.27	0.16
G6	39.55	-0.37	-0.09
G7	44.49	16.06	26.79
G8	64.97	15.89	16.79
G9	60.77	-30.19	40.76
G10	96.71	-0.64	2.01
H1	49.74	0.14	0.68
H2	38.29	-17.44	30.22
H3	20.76	31.66	-28.04
H4	81.43	2.41	88.98
H5	49.71	0.12	0.69
H6	60.04	0.09	0.05
H7	67.60	14.47	17.12
H8	64.75	17.30	18.88
H9	51.26	-50.65	43.80
H10	49.76	0.14	0.71
I1	8.10	0.19	-0.93
I2	51.36	9.52	-26.98
I3	71.62	-24.77	64.10
I4	48.75	57.24	-14.45
I5	34.85	-0.21	0.73
I6	75.36	0.35	0.26
I7	45.14	26.38	41.24
I8	36.20	16.70	27.06
I9	61.65	-54.33	46.18
I10	7.97	0.14	-0.80
J1	96.69	-0.67	1.95
J2	68.71	-35.41	-1.11
J3	70.39	19.37	79.73
J4	47.42	-30.91	-32.27
J5	15.43	-0.24	-0.25
J6	88.85	-0.59	0.25
J7	64.00	25.09	27.14
J8	66.65	22.21	28.81
J9	62.05	16.45	51.74
J10	96.71	-0.64	2.02
K1	49.72	0.12	0.64
K2	85.68	10.75	18.39
K3	89.35	-16.38	6.41
K4	84.59	5.21	-5.87
K5	83.63	-12.47	-8.89
K6	70.60	-0.24	0.07
K7	45.14	-0.04	0.86
K8	20.33	0.40	-0.21
K9	62.33	-14.54	54.58
K10	49.74	0.14	0.69
L1	8.08	0.13	-0.81
L2	23.03	33.95	8.88
L3	44.35	67.94	50.62
L4	60.91	36.55	4.15
L5	62.20	37.45	18.18
L6	63.33	51.30	81.88
L7	73.74	-11.45	85.07
L8	62.35	1.96	57.52
L9	72.77	-29.09	71.26
L10	8.13	0.15	-0.86
M1	49.71	0.12	0.62
M2	42.52	63.55	11.43
M3	18.09	32.61	-5.90
M4	40.66	65.54	31.98
M5	53.13	68.44	49.57
M6	82.08	23.39	87.24
M7	82.50	5.29	96.68
M8	71.90	-17.32	77.72
M9	21.95	13.41	16.36
M10	49.74	0.12	0.69
N1	96.79	-0.67	1.97
N2	49.78	0.12	0.65
N3	8.23	0.18	-0.82
N4	96.73	-0.67	1.99
N5	49.80	0.11	0.67
N6	8.18	0.15	-0.84
N7	96.73	-0.65	2.01
N8	49.75	0.13	0.67
N9	8.11	0.15	-0.90
N10	96.55	-0.64	2.02
END_DATA

ColorCheckerSG_generator.lua

--[[
function lab2rgb source:
https://github.com/antimatter15/rgb-lab/blob/master/color.js

ColorCheckerSG.txt source:
https://www.xrite.com/service-support/new_color_specifications_for_colorchecker_sg_and_classic_charts
http://www.xrite.com/-/media/XRite/Files/Literature/Misc/C/ColorCheckerSG_After_Nov2014.zip
/*
 * The data in this file is reported in CIE L* a* b* data for illuminant D50 and
 * 2 degree observer and is being supplied by X-Rite, Inc. This information can
 * be used for personal and educational but not for commercial purposes without 
 * license from X-rite, Inc.
 */
--]]

local datafile = arg[1] or "ColorCheckerSG_After_Nov2014.txt"

local function xy2coord(xy)
    local x = xy:sub(1,1):byte() - 64
    local y = tonumber(xy:sub(2))
    return x, y
end

local function lab2rgb(ll, la, lb)
    local y = (ll + 16) / 116
    local x = la / 500 + y
    local z = y - lb / 200
    local x3, y3, z3 = x^3, y^3, z^3
    x = 0.95047 * ((x3 > 0.008856) and x3 or (x - 16/116) / 7.787);
    y = 1.00000 * ((y3 > 0.008856) and y3 or (y - 16/116) / 7.787);
    z = 1.08883 * ((z3 > 0.008856) and z3 or (z - 16/116) / 7.787);
    local r = x *  3.2406 + y * -1.5372 + z * -0.4986;
    local g = x * -0.9689 + y *  1.8758 + z *  0.0415;
    local b = x *  0.0557 + y * -0.2040 + z *  1.0570;
    r = (r > 0.0031308) and (1.055 * math.pow(r, 1/2.4) - 0.055) or 12.92 * r;
    g = (g > 0.0031308) and (1.055 * math.pow(g, 1/2.4) - 0.055) or 12.92 * g;
    b = (b > 0.0031308) and (1.055 * math.pow(b, 1/2.4) - 0.055) or 12.92 * b;
    r = math.max(0, math.min(1, r)) * 255
    g = math.max(0, math.min(1, g)) * 255
    b = math.max(0, math.min(1, b)) * 255
    return string.format("%02x%02x%02x", r//1, g//1, b//1)
end

local function get_data(fn)
    local c = {}
    local r = io.open(fn, "r")
    local line
    while true do
        line = r:read("l")
        if "BEGIN_DATA" == line or not line then break end
    end
    while true do
        line = r:read("l")
        if "END_DATA" == line or not line then break end
        local xy, l, a, b = line:match("([%u][%d]+)\t([%d%.%-]+)\t([%d%.%-]+)\t([%d%.%-]+)")
        local x, y = xy2coord(xy)
        if not c[y] then c[y] = {} end
        c[y][x] = lab2rgb(l, a, b)
    end
    r:close()
    return c
end

local function save_svg(fn, c)
    local fmt_g = "<g id='%s%2d' transform='translate(%3d, %3d)'>"
    local fmt_p = "<path fill='#%s' d='M 0,0 V 40 H 40 V 0 Z'/>"
    
    local w = io.open(fn, "w+b")

    w:write("<svg version='1.1' viewBox='0 0 665 477' xmlns='http://www.w3.org/2000/svg'>\n")
    w:write("<path fill='#363636' d='M 0,0 V 477 H 665 V 0 Z' />\n")
    w:write("<g stroke='none' transform='translate(-40, -40)'>\n")
    for x = 1, 14 do
        for y = 1, 10 do
            w:write(fmt_g:format(string.char(x+64), y, x*47, y*47))
            w:write(fmt_p:format(c[y][x]))
            w:write("</g>\n")
        end
    end
    w:write("</g>\n")
    w:write("</svg>\n")
end

save_svg(datafile:gsub(".txt", ".svg"), get_data(datafile))