if not modules then modules = { } end modules ['colo-icc'] = { version = 1.000, comment = "companion to colo-ini.mkiv", author = "Hans Hagen, PRAGMA-ADE, Hasselt NL", copyright = "PRAGMA ADE / ConTeXt Development Team", license = "see context related readme files" } -- https://www.color.org/icc32.pdf etc local char, byte, gsub, match, format, strip = string.char, string.byte, string.gsub, string.match, string.format, string.strip local readstring, readnumber = io.readstring, io.readnumber local band = bit32.band local next = next local colors = attributes and attributes.colors or { } -- when used in mtxrun local report_colors = logs.reporter("colors","icc") local R, Cs, lpegmatch = lpeg.R, lpeg.Cs, lpeg.match local invalid = R(char(0)..char(31)) local cleaned = invalid^0 * Cs((1-invalid)^0) function colors.iccprofile(filename,verbose) local fullname = resolvers.findfile(filename,"icc") or "" if fullname == "" then local locate = resolvers.finders.byscheme -- not in mtxrun if locate then fullname = locate("loc",filename) end end if fullname == "" then report_colors("profile %a cannot be found",filename) return nil, false end local f = io.open(fullname,"rb") if not f then report_colors("profile %a cannot be loaded",fullname) return nil, false end local header = { size = readnumber(f,4), cmmtype = readnumber(f,4), version = readnumber(f,4), deviceclass = strip(readstring(f,4)), colorspace = strip(readstring(f,4)), connectionspace = strip(readstring(f,4)), datetime = { year = readnumber(f,2), month = readnumber(f,2), day = readnumber(f,2), hour = readnumber(f,2), minutes = readnumber(f,2), seconds = readnumber(f,2), }, filesignature = strip(readstring(f,4)), platformsignature = strip(readstring(f,4)), options = readnumber(f,4), devicemanufacturer = strip(readstring(f,4)), devicemodel = strip(readstring(f,4)), deviceattributes = readnumber(f,4), renderingintent = readnumber(f,4), illuminantxyz = { x = readnumber(f,4), y = readnumber(f,4), z = readnumber(f,4), }, profilecreator = readnumber(f,4), -- 84-127 -- id = strip(readstring(f,16)), --rubish } local tags = { } for i=1,readnumber(f,128,4) do tags[readstring(f,4)] = { offset = readnumber(f,4), length = readnumber(f,4), } end local o = header.options header.options = o == 0 and "embedded" or o == 1 and "dependent" or "unknown" local d = header.deviceattributes header.deviceattributes = { [band(d,1) ~= 0 and "transparency" or "reflective"] = true, [band(d,2) ~= 0 and "mate" or "glossy" ] = true, [band(d,3) ~= 0 and "negative" or "positive" ] = true, [band(d,4) ~= 0 and "bw" or "color" ] = true, } local r = header.renderingintent header.renderingintent = r == 0 and "perceptual" or r == 1 and "relative" or r == 2 and "saturation" or r == 3 and "absolute" or "unknown" for tag, spec in next, tags do if tag then local offset, length = spec.offset, spec.length local variant = readstring(f,offset,4) if variant == "text" or variant == "desc" then local str = readstring(f,length-4) tags[tag] = { data = str, cleaned = lpegmatch(cleaned,str), } else if verbose then report_colors("ignoring tag %a or type %a in profile %a",tag,variant,fullname) end tags[tag] = nil end end end f:close() local profile = { filename = filename, fullname = fullname, header = header, tags = tags, } report_colors("profile %a loaded",fullname) return profile, true end -- This is just some fun stuff I decided to check out when I was making sure that -- the 2020 metafun manual could be processed with lmtx 2021. Color conversion has -- been part of ConTeXt from the start but it has been extended to the less commonly -- used color spaces. We already do some CIE but didn't have lab converters to play -- with (although I had some MetaPost done for a friend long ago). So, when we moved -- to lmtx it made sense to also move some into the core. When searching for info -- I ran into some formulas for lab/xyz: http://www.easyrgb.com/en/math.php and -- http://www.brucelindbloom.com/ are useful resources. I didn't touch existing -- code (as it works ok). -- -- local illuminants = { -- 2=CIE 1931 10=CIE 1964 -- A = { [2] = { 109.850, 100, 35.585 }, [10] = { 111.144, 100, 35.200 } }, -- incandescent/tungsten -- B = { [2] = { 99.093, 100, 85.313 }, [10] = { 99.178, 100, 84.349 } }, -- old direct sunlight at noon -- C = { [2] = { 98.074, 100, 118.232 }, [10] = { 97.285, 100, 116.145 } }, -- old daylight -- D50 = { [2] = { 96.422, 100, 82.521 }, [10] = { 96.720, 100, 81.427 } }, -- icc profile pcs -- D55 = { [2] = { 95.682, 100, 92.149 }, [10] = { 95.799, 100, 90.926 } }, -- mid-morning daylight -- D65 = { [2] = { 95.047, 100, 108.883 }, [10] = { 94.811, 100, 107.304 } }, -- daylight, srgb, adobe-rgb -- D75 = { [2] = { 94.972, 100, 122.638 }, [10] = { 94.416, 100, 120.641 } }, -- north sky daylight -- E = { [2] = { 100.000, 100, 100.000 }, [10] = { 100.000, 100, 100.000 } }, -- equal energy -- F1 = { [2] = { 92.834, 100, 103.665 }, [10] = { 94.791, 100, 103.191 } }, -- daylight fluorescent -- F2 = { [2] = { 99.187, 100, 67.395 }, [10] = { 103.280, 100, 69.026 } }, -- cool fluorescent -- F3 = { [2] = { 103.754, 100, 49.861 }, [10] = { 108.968, 100, 51.965 } }, -- white fluorescent -- F4 = { [2] = { 109.147, 100, 38.813 }, [10] = { 114.961, 100, 40.963 } }, -- warm white fluorescent -- F5 = { [2] = { 90.872, 100, 98.723 }, [10] = { 93.369, 100, 98.636 } }, -- daylight fluorescent -- F6 = { [2] = { 97.309, 100, 60.191 }, [10] = { 102.148, 100, 62.074 } }, -- lite white fluorescent -- F7 = { [2] = { 95.044, 100, 108.755 }, [10] = { 95.792, 100, 107.687 } }, -- daylight fluorescent, d65 simulator -- F8 = { [2] = { 96.413, 100, 82.333 }, [10] = { 97.115, 100, 81.135 } }, -- sylvania f40, d50 simulator -- F9 = { [2] = { 100.365, 100, 67.868 }, [10] = { 102.116, 100, 67.826 } }, -- cool white fluorescent -- F10 = { [2] = { 96.174, 100, 81.712 }, [10] = { 99.001, 100, 83.134 } }, -- ultralume 50, philips tl85 -- F11 = { [2] = { 100.966, 100, 64.370 }, [10] = { 103.866, 100, 65.627 } }, -- ultralume 40, philips tl84 -- F12 = { [2] = { 108.046, 100, 39.228 }, [10] = { 111.428, 100, 40.353 } }, -- ultralume 30, philips tl83 -- } -- -- local D65 = illuminants.D65 -- local D652 = { 95.047, 100, 108.883 } -- -- local function labref(illuminate,observer) -- local r = illuminants[illuminant or "D65"] or D65 -- return r[observer or 2] or r[2] or D652 -- end -- -- This is hardly useful but nice for metafun demos: ----- default = { 95.047, 100, 108.883 } -- D652 local default = { 96.422, 100, 82.521 } -- D502 ----- default = { 96.720, 100, 81.427 } -- D510 local function xyztolab(x,y,z,mapping) if not mapping then mapping = default end x = x / mapping[1] y = y / mapping[2] z = z / mapping[3] x = (x > 0.008856) and x^(1/3) or (7.787 * x) + (16/116) y = (y > 0.008856) and y^(1/3) or (7.787 * y) + (16/116) z = (z > 0.008856) and z^(1/3) or (7.787 * z) + (16/116) return 116 * y - 16, 500 * (x - y), 200 * (y - z) end local function labtoxyz(l,a,b,mapping) if not mapping then mapping = default end local y = (l + 16) / 116 local x = a / 500 + y local z = y - b / 200 return mapping[1] * ((x^3 > 0.008856) and x^3 or (x - 16/116) / 7.787), mapping[2] * ((y^3 > 0.008856) and y^3 or (y - 16/116) / 7.787), mapping[3] * ((z^3 > 0.008856) and z^3 or (z - 16/116) / 7.787) end local function xyztorgb(x,y,z) -- D65/2° -- local r = (x * 3.2404542 + y * -1.5371385 + z * -0.4985314) / 100 -- local g = (x * -0.9692660 + y * 1.8760108 + z * 0.0415560) / 100 -- local b = (x * 0.0556434 + y * -0.2040259 + z * 1.0572252) / 100 -- D50/2° local r = (x * 3.1338561 + y * -1.6168667 + z * -0.4906146) / 100 local g = (x * -0.9787684 + y * 1.9161415 + z * 0.0334540) / 100 local b = (x * 0.0719453 + y * -0.2289914 + z * 1.4052427) / 100 -- r = (r > 0.0031308) and (1.055 * r^(1/2.4) - 0.055) or (12.92 * r) g = (g > 0.0031308) and (1.055 * g^(1/2.4) - 0.055) or (12.92 * g) b = (b > 0.0031308) and (1.055 * b^(1/2.4) - 0.055) or (12.92 * b) if r < 0 then r = 0 elseif r > 1 then r = 1 end if g < 0 then g = 0 elseif g > 1 then g = 1 end if b < 0 then b = 0 elseif b > 1 then b = 1 end return r, g, b end local function rgbtoxyz(r,g,b) r = 100 * ((r > 0.04045) and ((r + 0.055)/1.055)^2.4 or (r / 12.92)) g = 100 * ((g > 0.04045) and ((g + 0.055)/1.055)^2.4 or (g / 12.92)) b = 100 * ((b > 0.04045) and ((b + 0.055)/1.055)^2.4 or (b / 12.92)) return r * 0.4124 + g * 0.3576 + b * 0.1805, r * 0.2126 + g * 0.7152 + b * 0.0722, r * 0.0193 + g * 0.1192 + b * 0.9505 end local function labtorgb(l,a,b,mapping) return xyztorgb(labtoxyz(l,a,b,mapping)) end colors.xyztolab = xyztolab colors.labtoxyz = labtoxyz colors.xyztorgb = xyztorgb colors.rgbtoxyz = rgbtoxyz colors.labtorgb = labtorgb return colors