292 lines
8.5 KiB
Lua
292 lines
8.5 KiB
Lua
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--[[
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Lua implementation of HSLuv and HPLuv color spaces
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Homepage: http://www.hsluv.org/
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Copyright (C) 2019 Alexei Boronine
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Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
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associated documentation files (the "Software"), to deal in the Software without restriction, including
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without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the
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following conditions:
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The above copyright notice and this permission notice shall be included in all copies or substantial
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portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
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LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
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NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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]] local hsluv = {}
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local hexChars = "0123456789abcdef"
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local distance_line_from_origin = function(line)
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return math.abs(line.intercept) / math.sqrt((line.slope ^ 2) + 1)
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end
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local length_of_ray_until_intersect = function(theta, line)
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return line.intercept / (math.sin(theta) - line.slope * math.cos(theta))
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end
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hsluv.get_bounds = function(l)
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local result = {};
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local sub2;
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local sub1 = ((l + 16) ^ 3) / 1560896;
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if sub1 > hsluv.epsilon then
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sub2 = sub1;
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else
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sub2 = l / hsluv.kappa;
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end
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for i = 1, 3 do
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local m1 = hsluv.m[i][1];
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local m2 = hsluv.m[i][2];
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local m3 = hsluv.m[i][3];
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for t = 0, 1 do
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local top1 = (284517 * m1 - 94839 * m3) * sub2;
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local top2 = (838422 * m3 + 769860 * m2 + 731718 * m1) * l * sub2 - 769860 * t * l;
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local bottom = (632260 * m3 - 126452 * m2) * sub2 + 126452 * t;
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table.insert(result, { slope = top1 / bottom, intercept = top2 / bottom })
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end
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end
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return result
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end
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hsluv.max_safe_chroma_for_l = function(l)
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local bounds = hsluv.get_bounds(l);
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local min = 1.7976931348623157e+308;
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for i = 1, 6 do
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local length = distance_line_from_origin(bounds[i]);
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if length >= 0 then min = math.min(min, length); end
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end
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return min;
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end
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hsluv.max_safe_chroma_for_lh = function(l, h)
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local hrad = h / 360 * math.pi * 2;
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local bounds = hsluv.get_bounds(l);
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local min = 1.7976931348623157e+308;
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for i = 1, 6 do
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local bound = bounds[i];
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local length = length_of_ray_until_intersect(hrad, bound);
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if length >= 0 then min = math.min(min, length); end
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end
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return min
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end
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hsluv.dot_product = function(a, b)
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local sum = 0;
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for i = 1, 3 do sum = sum + a[i] * b[i]; end
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return sum
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end
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hsluv.from_linear = function(c)
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if c <= 0.0031308 then
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return 12.92 * c
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else
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return 1.055 * (c ^ 0.416666666666666685) - 0.055
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end
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end
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hsluv.to_linear = function(c)
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if c > 0.04045 then
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return ((c + 0.055) / 1.055) ^ 2.4
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else
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return c / 12.92
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end
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end
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hsluv.xyz_to_rgb = function(tuple)
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return {
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hsluv.from_linear(hsluv.dot_product(hsluv.m[1], tuple)),
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hsluv.from_linear(hsluv.dot_product(hsluv.m[2], tuple)),
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hsluv.from_linear(hsluv.dot_product(hsluv.m[3], tuple)),
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}
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end
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hsluv.rgb_to_xyz = function(tuple)
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local rgbl = { hsluv.to_linear(tuple[1]), hsluv.to_linear(tuple[2]), hsluv.to_linear(tuple[3]) };
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return {
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hsluv.dot_product(hsluv.minv[1], rgbl),
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hsluv.dot_product(hsluv.minv[2], rgbl),
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hsluv.dot_product(hsluv.minv[3], rgbl),
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}
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end
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hsluv.y_to_l = function(Y)
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if Y <= hsluv.epsilon then
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return Y / hsluv.refY * hsluv.kappa
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else
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return 116 * ((Y / hsluv.refY) ^ 0.333333333333333315) - 16
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end
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end
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hsluv.l_to_y = function(L)
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if L <= 8 then
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return hsluv.refY * L / hsluv.kappa
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else
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return hsluv.refY * (((L + 16) / 116) ^ 3)
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end
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end
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hsluv.xyz_to_luv = function(tuple)
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local X = tuple[1];
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local Y = tuple[2];
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local divider = X + 15 * Y + 3 * tuple[3];
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local varU = 4 * X;
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local varV = 9 * Y;
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if divider ~= 0 then
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varU = varU / divider;
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varV = varV / divider;
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else
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varU = 0;
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varV = 0;
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end
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local L = hsluv.y_to_l(Y);
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if L == 0 then return { 0, 0, 0 } end
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return { L, 13 * L * (varU - hsluv.refU), 13 * L * (varV - hsluv.refV) }
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end
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hsluv.luv_to_xyz = function(tuple)
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local L = tuple[1];
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local U = tuple[2];
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local V = tuple[3];
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if L == 0 then return { 0, 0, 0 } end
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local varU = U / (13 * L) + hsluv.refU;
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local varV = V / (13 * L) + hsluv.refV;
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local Y = hsluv.l_to_y(L);
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local X = 0 - (9 * Y * varU) / ((((varU - 4) * varV) - varU * varV));
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return { X, Y, (9 * Y - 15 * varV * Y - varV * X) / (3 * varV) }
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end
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hsluv.luv_to_lch = function(tuple)
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local L = tuple[1];
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local U = tuple[2];
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local V = tuple[3];
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local C = math.sqrt(U * U + V * V);
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local H
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if C < 0.00000001 then
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H = 0;
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else
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H = math.atan2(V, U) * 180.0 / 3.1415926535897932;
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if H < 0 then H = 360 + H; end
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end
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return { L, C, H }
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end
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hsluv.lch_to_luv = function(tuple)
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local L = tuple[1];
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local C = tuple[2];
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local Hrad = tuple[3] / 360.0 * 2 * math.pi;
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return { L, math.cos(Hrad) * C, math.sin(Hrad) * C };
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end
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hsluv.hsluv_to_lch = function(tuple)
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local H = tuple[1];
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local S = tuple[2];
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local L = tuple[3];
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if L > 99.9999999 then return { 100, 0, H } end
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if L < 0.00000001 then return { 0, 0, H } end
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return { L, hsluv.max_safe_chroma_for_lh(L, H) / 100 * S, H }
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end
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hsluv.lch_to_hsluv = function(tuple)
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local L = tuple[1];
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local C = tuple[2];
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local H = tuple[3];
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local max_chroma = hsluv.max_safe_chroma_for_lh(L, H)
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if L > 99.9999999 then return { H, 0, 100 } end
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if L < 0.00000001 then return { H, 0, 0 } end
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return { H, C / max_chroma * 100, L }
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end
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hsluv.hpluv_to_lch = function(tuple)
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local H = tuple[1];
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local S = tuple[2];
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local L = tuple[3];
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if L > 99.9999999 then return { 100, 0, H } end
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if L < 0.00000001 then return { 0, 0, H } end
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return { L, hsluv.max_safe_chroma_for_l(L) / 100 * S, H }
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end
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hsluv.lch_to_hpluv = function(tuple)
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local L = tuple[1];
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local C = tuple[2];
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local H = tuple[3];
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if L > 99.9999999 then return { H, 0, 100 } end
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if L < 0.00000001 then return { H, 0, 0 } end
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return { H, C / hsluv.max_safe_chroma_for_l(L) * 100, L }
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end
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hsluv.rgb_to_hex = function(tuple)
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local h = "#";
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for i = 1, 3 do
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local c = math.floor(tuple[i] * 255 + 0.5);
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local digit2 = math.fmod(c, 16);
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local x = (c - digit2) / 16;
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local digit1 = math.floor(x);
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h = h .. string.sub(hexChars, digit1 + 1, digit1 + 1)
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h = h .. string.sub(hexChars, digit2 + 1, digit2 + 1)
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end
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return h
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end
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hsluv.hex_to_rgb = function(hex)
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hex = string.lower(hex)
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local ret = {}
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for i = 0, 2 do
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local char1 = string.sub(hex, i * 2 + 2, i * 2 + 2);
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local char2 = string.sub(hex, i * 2 + 3, i * 2 + 3);
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local digit1 = string.find(hexChars, char1) - 1
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local digit2 = string.find(hexChars, char2) - 1
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ret[i + 1] = (digit1 * 16 + digit2) / 255.0;
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end
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return ret
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end
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hsluv.lch_to_rgb = function(tuple) return
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hsluv.xyz_to_rgb(hsluv.luv_to_xyz(hsluv.lch_to_luv(tuple))) end
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hsluv.rgb_to_lch = function(tuple) return
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hsluv.luv_to_lch(hsluv.xyz_to_luv(hsluv.rgb_to_xyz(tuple))) end
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hsluv.hsluv_to_rgb = function(tuple) return hsluv.lch_to_rgb(hsluv.hsluv_to_lch(tuple)) end
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hsluv.rgb_to_hsluv = function(tuple) return hsluv.lch_to_hsluv(hsluv.rgb_to_lch(tuple)) end
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hsluv.hpluv_to_rgb = function(tuple) return hsluv.lch_to_rgb(hsluv.hpluv_to_lch(tuple)) end
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hsluv.rgb_to_hpluv = function(tuple) return hsluv.lch_to_hpluv(hsluv.rgb_to_lch(tuple)) end
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hsluv.hsluv_to_hex = function(tuple) return hsluv.rgb_to_hex(hsluv.hsluv_to_rgb(tuple)) end
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hsluv.hpluv_to_hex = function(tuple) return hsluv.rgb_to_hex(hsluv.hpluv_to_rgb(tuple)) end
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hsluv.hex_to_hsluv = function(s) return hsluv.rgb_to_hsluv(hsluv.hex_to_rgb(s)) end
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hsluv.hex_to_hpluv = function(s) return hsluv.rgb_to_hpluv(hsluv.hex_to_rgb(s)) end
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hsluv.m = {
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{ 3.240969941904521, -1.537383177570093, -0.498610760293 },
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{ -0.96924363628087, 1.87596750150772, 0.041555057407175 },
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{ 0.055630079696993, -0.20397695888897, 1.056971514242878 },
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}
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hsluv.minv = {
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{ 0.41239079926595, 0.35758433938387, 0.18048078840183 },
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{ 0.21263900587151, 0.71516867876775, 0.072192315360733 },
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{ 0.019330818715591, 0.11919477979462, 0.95053215224966 },
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}
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hsluv.refY = 1.0
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hsluv.refU = 0.19783000664283
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hsluv.refV = 0.46831999493879
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hsluv.kappa = 903.2962962
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hsluv.epsilon = 0.0088564516
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return hsluv
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