>Hike395: protect against junk value

2024-09-23T02:01:10Z

protect against junk value

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-- Introduction: https://colorspace.r-forge.r-project.org/articles/color_spaces.html

local p = {}

local function isempty(v)
return v == nil or v == ''
end

local function hexToRgb(color)
local cleanColor = color:gsub("#", "#"):match('^[%s#]*(.-)[%s;]*$')
if (#cleanColor == 6) then
return {
r = tonumber(string.sub(cleanColor, 1, 2), 16),
g = tonumber(string.sub(cleanColor, 3, 4), 16),
b = tonumber(string.sub(cleanColor, 5, 6), 16)
}
elseif (#cleanColor == 3) then
return {
r = 17 * tonumber(string.sub(cleanColor, 1, 1), 16),
g = 17 * tonumber(string.sub(cleanColor, 2, 2), 16),
b = 17 * tonumber(string.sub(cleanColor, 3, 3), 16)
}
end
error("Invalid hexadecimal color " .. cleanColor, 1)
end

local function round(v)
if (v < 0) then
return math.ceil(v - 0.5)
else
return math.floor(v + 0.5)
end
end

local function rgbToHex(r, g, b)
return string.format("%02X%02X%02X", round(r), round(g), round(b))
end

local function rgbToCmyk(r, g, b)
if (r > 255 or g > 255 or b > 255 or r < 0 or g < 0 or b < 0) then
error("Color level out of bounds")
end
local c = 1 - r / 255
local m = 1 - g / 255
local y = 1 - b / 255
local k = math.min(c, m, y)
if (k == 1) then
c = 0
m = 0
y = 0
else
local d = 1 - k
c = (c - k) / d
m = (m - k) / d
y = (y - k) / d
end
return { c = c * 100, m = m * 100, y = y * 100, k = k * 100 }
end

local function rgbToHsl(r, g, b)
if (r > 255 or g > 255 or b > 255 or r < 0 or g < 0 or b < 0) then
error("Color level out of bounds")
end
local channelMax = math.max(r, g, b)
local channelMin = math.min(r, g, b)
local range = channelMax - channelMin
local h, s
if (range == 0) then
h = 0
elseif (channelMax == r) then
h = 60 * ((g - b) / range)
if (h < 0) then
h = 360 + h
end
elseif (channelMax == g) then
h = 60 * (2 + (b - r) / range)
else
h = 60 * (4 + (r - g) / range)
end
local L = channelMax + channelMin
if (L == 0 or L == 510) then
s = 0
else
s = 100 * range / math.min(L, 510 - L)
end
return { h = h, s = s, l = L * 50 / 255 }
end

local function rgbToHsv(r, g, b)
if (r > 255 or g > 255 or b > 255 or r < 0 or g < 0 or b < 0) then
error("Color level out of bounds")
end
local channelMax = math.max(r, g, b)
local channelMin = math.min(r, g, b)
local range = channelMax - channelMin
local h, s
if (range == 0) then
h = 0
elseif (channelMax == r) then
h = 60 * ((g - b) / range)
if (h < 0) then
h = 360 + h
end
elseif (channelMax == g) then
h = 60 * (2 + (b - r) / range)
else
h = 60 * (4 + (r - g) / range)
end
if (channelMax == 0) then
s = 0
else
s = 100 * range / channelMax
end
return { h = h, s = s, v = channelMax * 100 / 255 }
end

-- c in [0, 255], condition tweaked for no discontinuity
-- http://entropymine.com/imageworsener/srgbformula/
local function toLinear(c)
if (c > 10.314300250662591) then
return math.pow((c + 14.025) / 269.025, 2.4)
else
return c / 3294.6
end
end

local function toNonLinear(c)
if (c > 0.00313066844250063) then
return 269.025 * math.pow(c, 1.0/2.4) - 14.025
else
return 3294.6 * c
end
end

local function srgbToCielchuvD65o2deg(r, g, b)
if (r > 255 or g > 255 or b > 255 or r < 0 or g < 0 or b < 0) then
error("Color level out of bounds")
end
local R = toLinear(r)
local G = toLinear(g)
local B = toLinear(b)
-- https://github.com/w3c/csswg-drafts/issues/5922
local X = 0.1804807884018343 * B + 0.357584339383878 * G + 0.41239079926595934 * R
local Y = 0.07219231536073371 * B + 0.21263900587151027 * R + 0.715168678767756 * G
local Z = 0.01933081871559182 * R + 0.11919477979462598 * G + 0.9505321522496607 * B
local L, C, h
if (Y > 0.00885645167903563082) then
L = 116 * math.pow(Y, 1/3) - 16
else
L = Y * 903.2962962962962962963
end
if ((r == g and g == b) or L == 0) then
C = 0
h = 0
else
d = X + 3 * Z + 15 * Y
if (d == 0) then
C = 0
h = 0
else
-- 0.19783... and 0.4631... computed with extra precision from (X,Y,Z) when (R,G,B) = (1,1,1),
-- in which case (u,v) ≈ (0,0)
local us = 4 * X / d - 0.19783000664283678994
local vs = 9 * Y / d - 0.46831999493879099801
h = math.atan2(vs, us) * 57.2957795130823208768
if (h < 0) then
h = h + 360
elseif (h == 0) then
h = 0 -- ensure zero is positive
end
C = math.sqrt(us * us + vs * vs) * 13 * L
if (C == 0) then
C = 0
h = 0
end
end
end
return { L = L, C = C, h = h }
end

local function srgbMix(t, r0, g0, b0, r1, g1, b1)
if (t > 1 or t < 0) then
error("Interpolation parameter out of bounds")
end
if (r0 > 255 or g0 > 255 or b0 > 255 or r1 > 255 or g1 > 255 or b1 > 255 or r0 < 0 or g0 < 0 or b0 < 0 or r1 < 0 or g1 < 0 or b1 < 0) then
error("Color level out of bounds")
end
local tc = 1 - t
return {
r = toNonLinear(tc * toLinear(r0) + t * toLinear(r1)),
g = toNonLinear(tc * toLinear(g0) + t * toLinear(g1)),
b = toNonLinear(tc * toLinear(b0) + t * toLinear(b1))
}
end

local function formatToPrecision(value, p)
return string.format("%." .. p .. "f", value)
end

local function getFractionalZeros(p)
if (p > 0) then
return "." .. string.rep("0", p)
else
return ""
end
end

function p.hexToRgbTriplet(frame)
local args = frame.args or frame:getParent().args
local hex = args[1]
if (hex) then
local rgb = hexToRgb(hex)
return rgb.r .. ', ' .. rgb.g .. ', ' .. rgb.b
else
return ""
end
end

function p.rgbTripletToHex(frame)
local args = frame.args or frame:getParent().args
local r = tonumber(args[1])
local g = tonumber(args[2])
local b = tonumber(args [3])
if (isempty(r) or isempty(g) or isempty(b)) then
return ""
else
return rgbToHex(r,g,b)
end
end

function p.hexToCmyk(frame)
local args = frame.args or frame:getParent().args
local hex = args[1]
if (hex) then
local p = tonumber(args.precision) or 0
local s = args.pctsign or "1"
local rgb = hexToRgb(hex)
local cmyk = rgbToCmyk(rgb.r, rgb.g, rgb.b)
local fk = formatToPrecision(cmyk.k, p)
local fc, fm, fy
local fracZeros = getFractionalZeros(p)
if (fk == 100 .. fracZeros) then
local fZero = 0 .. fracZeros
fc = fZero
fm = fZero
fy = fZero
else
fc = formatToPrecision(cmyk.c, p)
fm = formatToPrecision(cmyk.m, p)
fy = formatToPrecision(cmyk.y, p)
end
if (s ~= "0") then
return fc .. "%, " .. fm .. "%, " .. fy .. "%, " .. fk .. "%"
else
return fc .. ", " .. fm .. ", " .. fy .. ", " .. fk
end
else
return ""
end
end

function p.hexToHsl(frame)
local args = frame.args or frame:getParent().args
local hex = args[1]
if (hex) then
local p = tonumber(args.precision) or 0
local rgb = hexToRgb(hex)
local hsl = rgbToHsl(rgb.r, rgb.g, rgb.b)
local fl = formatToPrecision(hsl.l, p)
local fs, fh
local fracZeros = getFractionalZeros(p)
local fZero = 0 .. fracZeros
if (fl == fZero or fl == 100 .. fracZeros) then
fs = fZero
fh = fZero
else
fs = formatToPrecision(hsl.s, p)
if (fs == fZero) then
fh = fZero
else
fh = formatToPrecision(hsl.h, p)
if (fh == 360 .. fracZeros) then
fh = fZero -- handle rounding to 360
end
end
end
return fh .. "°, " .. fs .. "%, " .. fl .. "%"
else
return ""
end
end

function p.hexToHsv(frame)
local args = frame.args or frame:getParent().args
local hex = args[1]
if (hex) then
local p = tonumber(args.precision) or 0
local rgb = hexToRgb(hex)
local hsv = rgbToHsv(rgb.r, rgb.g, rgb.b)
local fv = formatToPrecision(hsv.v, p)
local fs, fh
local fracZeros = getFractionalZeros(p)
local fZero = 0 .. fracZeros
if (fv == fZero) then
fh = fZero
fs = fZero
else
fs = formatToPrecision(hsv.s, p)
if (fs == fZero) then
fh = fZero
else
fh = formatToPrecision(hsv.h, p)
if (fh == 360 .. fracZeros) then
fh = fZero -- handle rounding to 360
end
end
end
return fh .. "°, " .. fs .. "%, " .. fv .. "%"
else
return ""
end
end

function p.hexToCielch(frame)
local args = frame.args or frame:getParent().args
local hex = args[1]
if (hex) then
local p = tonumber(args.precision) or 0
local rgb = hexToRgb(hex)
local LCh = srgbToCielchuvD65o2deg(rgb.r, rgb.g, rgb.b)
local fL = formatToPrecision(LCh.L, p)
local fC, fh
local fracZeros = getFractionalZeros(p)
local fZero = 0 .. fracZeros
if (fL == fZero or fL == 100 .. fracZeros) then
fC = fZero
fh = fZero
else
fC = formatToPrecision(LCh.C, p)
if (fC == fZero) then
fh = fZero
else
fh = formatToPrecision(LCh.h, p)
if (fh == 360 .. fracZeros) then
fh = fZero -- handle rounding to 360
end
end
end
return fL .. ", " .. fC .. ", " .. fh .. "°"
else
return ""
end
end

function p.hexMix(frame)
local args = frame.args or frame:getParent().args
local hex0 = args[1]
local hex1 = args[2]
if (isempty(hex0) or isempty(hex1)) then
return ""
end
local t = tonumber(args[3])
if not t then
t = 0.5
else
local min = tonumber(args.min) or 0
local max = tonumber(args.max) or 100
if (min >= max) then
error("Minimum proportion greater than or equal to maximum")
elseif (t < min) then
t = 0
elseif (t > max) then
t = 1
else
t = (t - min) / (max - min)
end
end
local rgb0 = hexToRgb(hex0)
local rgb1 = hexToRgb(hex1)
local rgb = srgbMix(t, rgb0.r, rgb0.g, rgb0.b, rgb1.r, rgb1.g, rgb1.b)
return rgbToHex(rgb.r, rgb.g, rgb.b)
end

return p

Module:Color - Revision history

>Hike395: protect against junk value