Invert brightness of #RRGGBB values references in text. Used to transform tmTheme files to with with NegativeScreen

invcol.rb

require 'matrix' 

@inversionmatrix = Matrix[
	[  0.3333333, -0.6666667, -0.6666667,  0.0000000,  0.0000000 ],
	[ -0.6666667,  0.3333333, -0.6666667,  0.0000000,  0.0000000 ],
	[ -0.6666667, -0.6666667,  0.3333333,  0.0000000,  0.0000000 ],
	[  0.0000000,  0.0000000,  0.0000000,  1.0000000,  0.0000000 ],
	[  1.0000000,  1.0000000,  1.0000000,  0.0000000,  1.0000000 ]]

def inv_m_str(str)
	inv_m( str[0,2],str[2,2],str[4,2])
end

def inv_m(r,g,b,a = "ff")
	to_hexstring(to_vector(r,g,b,a) * @inversionmatrix)
end

def to_hexstring(vector)
	vector.to_a[0][0,3].map{|v| to_hex(v)}.join("")
end

def to_vector(r,g,b,a)
	rd = to_dec(r)
	gd = to_dec(g)
	bd = to_dec(b)
	ad = to_dec(a)

	Matrix.row_vector([rd,gd,bd,ad,1.0])
end

def to_dec(hexstr)
	hexstr.to_i(16).to_f / 0xff
end

def to_hex(decimal)
	val = decimal * 0xff
	return "00" if(decimal <=0 )
	return "FF" if(decimal >= 255)
	(val).to_i.to_s(16).upcase.rjust(2,'0')
end


puts ARGF.read.gsub(/(?<=#)[0-9a-fA-Z]{6}(?![0-9a-zA-Z])/){|match| inv_m_str match } #.gsub(/(?<=#)[0-9a-fA-Z]{3}(?![0-9a-zA-Z])/){|match| invertcharstring match }

InvertCol.md

Takes a file. Returns (stdout) a version with all references to colors in the format #rrggbb replaced with the inverse color (where inverse means the brightness is inverted)

I use this with NegativeScreen.exe and Chrome plugin "Deluminate" to make most apps have a black background.