Module:Sandbox/AlexNB/nmColor: Difference between revisions

Revision as of 22:01, 19 October 2013

Latest revision as of 23:15, 27 September 2014

(161 intermediate revisions by the same user not shown)

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local bluevalue = 0

local function nm2RGB(wavelength, IFcorrect)

-- code based on an algorithm from Dan Bruton's Color Science Page: http://www.physics.sfasu.edu/astro/color/spectra.html

-- calculating RGB color components

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greenvalue = (645 - wavelength) / 65

bluevalue = 0

elseif (wavelength >= 645) and (wavelength <= 780) then

redvalue = 1

greenvalue = 0

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end

-- calculating intensity correction factor

if IFcorrect then

local intensityfactor = 0

if (wavelength >= 380) and (wavelength < 420) then

intensityfactor = 0.3 + 0.7*(wavelength - 350) / 70

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elseif (wavelength > 700) and (wavelength <= 780) then

intensityfactor = 0.3 + 0.7*(780 - wavelength) / 80

else

intensityfactor = 0

end

redvalue = redvalue * intensityfactor

greenvalue = greenvalue * intensityfactor

bluevalue = bluevalue * intensityfactor

elseend

end

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-- this function returns the string "#RRGGBB" with approximate RGB value for a wavelength passed as a first argument

local wavelength = tonumber(frame.args[1])

nm2RGB(wavelength, true)

local result='#' .. string.format("%.2X%.2X%.2X", 255*redvalue, 255*greenvalue, 255*bluevalue)

return result

end

local function absorption_to_visible(wavelength_abs)

-- code based on a color wheel drawn at: http://www2.chemistry.msu.edu/faculty/reusch/virttxtjml/spectrpy/uv-vis/spectrum.htm

local wavelength_vis

local minVioletIndigo = 380 -- originally, it was 400

local maxVioletIndigo = 430

local widthVioletIndigo = maxVioletIndigo - minVioletIndigo

local minBlue = 430

local maxBlue = 490

local widthBlue = maxBlue - minBlue

local minGreen = 490

local maxGreen = 560

local widthGreen = maxGreen - minGreen

local minYellow = 560

local maxYellow = 580

local widthYellow = maxYellow - minYellow

local minOrange = 580

local maxOrange = 650 -- originally, it was 620

local widthOrange = maxOrange - minOrange

local minRed = 650 -- originally, it was 620

local maxRed = 780 -- originally, it was 800

local widthRed = maxRed - minRed

if (wavelength_abs>=minVioletIndigo) and (wavelength_abs<=maxVioletIndigo) then

wavelength_vis = (wavelength_abs - minVioletIndigo)*widthYellow/widthVioletIndigo + minYellow

elseif (wavelength_abs>minBlue) and (wavelength_abs<=maxBlue) then

wavelength_vis = (wavelength_abs - minBlue)*widthOrange/widthBlue + minOrange

elseif (wavelength_abs>minGreen) and (wavelength_abs<=maxGreen) then

wavelength_vis = (wavelength_abs - minGreen)*widthRed/widthGreen + minRed

elseif (wavelength_abs>minYellow) and (wavelength_abs<=maxYellow) then

wavelength_vis = (wavelength_abs - minYellow)*widthVioletIndigo/widthYellow + minVioletIndigo

elseif (wavelength_abs>minOrange) and (wavelength_abs<=maxOrange) then

wavelength_vis = (wavelength_abs - minOrange)*widthBlue/widthOrange + minBlue

elseif (wavelength_abs>minRed) and (wavelength_abs<=maxRed) then

wavelength_vis = (wavelength_abs - minRed)*widthGreen/(widthRed + 20) + minGreen

-- one of the "corrected" versions: wavelength_vis = (wavelength_abs - minRed - 30)*widthGreen/widthRed + minGreen

end

return wavelength_vis

end

local minAntiMagenta = 550

local maxAntiMagenta = 570

local function process_magenta(wavelength_abs)

local redvalue_RED

local bluevalue_RED

local greenvalue_RED

local redvalue_BLUE

local bluevalue_BLUE

local greenvalue_BLUE

local widthAntiMagenta = maxAntiMagenta - minAntiMagenta

local bias_BLUE = (wavelength_abs - minAntiMagenta)/widthAntiMagenta

local bias_RED = (maxAntiMagenta - wavelength_abs)/widthAntiMagenta

nm2RGB(wavelength700, false)

redvalue_RED = redvalue*bias_RED

bluevalue_RED = bluevalue*bias_RED

greenvalue_RED = greenvalue*bias_RED

nm2RGB(400, false)

redvalue_BLUE = redvalue*bias_BLUE

bluevalue_BLUE = bluevalue*bias_BLUE

greenvalue_BLUE = greenvalue*bias_BLUE

redvalue = 0.6+ 0.4*(redvalue_RED + redvalue_BLUE)

bluevalue = 0.7 + 0.3*(bluevalue_RED + bluevalue_BLUE)

greenvalue = greenvalue_RED + greenvalue_BLUE

end

function p.absorption(frame)

-- this function returns the string "#RRGGBB" with approximate RGB value for a complementary color (reflection) to a color, defined as a wavelength passed as a first argument

-- The following formula is used for the complimentary color: {0xFF - RR, 0xFF - (RR + BB)/2, 0xFF - BB}

local wavelength = tonumber(frame.args[1])

-- adding magentas to smoothen red->blue transition. Trying 540..570 nm

nm2RGB(wavelength)

if (wavelength>=minAntiMagenta) and (wavelength<=maxAntiMagenta) then

-- local result='#' .. string.format("%.2X%.2X%.2X", 255*(1-redvalue), 255*(1-greenvalue), 255*(1-bluevalue))

process_magenta(wavelength)

local result='#' .. string.format("%.2X%.2X%.2X", 255*((greenvalue+bluevalue)/3), 255*((redvalue+bluevalue)/3), 255*((redvalue+greenvalue)/3))

else nm2RGB(absorption_to_visible(wavelength), false)

end

-- local result='#' .. string.format("%.2X%.2X%.2X", 255*(1-redvalue), 255*(1-greenvalue), 255*(1-bluevalue))

return result

end

return p