hsv to rgb with rational numbers
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function mulRat(op1n, op1d, op2n, op2d)
return op1n * op2n, op1d * op2d
end
function divRat(op1n, op1d, op2n, op2d)
return op1n * op2d, op1d * op2n
end
function subRat(op1n, op1d, op2n, op2d)
return op1n * op2d - op2n * op1d, op1d * op2d
end
function addRat(op1n, op1d, op2n, op2d)
return op1n * op2d + op2n * op1d, op1d * op2d
end
function hsvRational(hn, hd, sn, sd, vn, vd)
if sn == 0 then
local rn, rd = mulRat(vn, vd, 255, 1)
local result = rn / rd
return result, result, result
end
local h1n, h1d = mulRat(hn, hd, 6, 1)
local index = math.floor(h1n / h1d)
local fn, fd = subRat(h1n, h1d, index, 1)
local p1n, p1d = subRat(1, 1, sn, sd)
local pn , pd = mulRat(vn, vd, p1n, p1d)
local q1n, q1d = mulRat(sn, sd, fn, fd)
local q2n, q2d = subRat(1, 1, q1n, q1d)
local qn , qd = mulRat(vn, vd, q2n, q2d)
local t1n, t1d = subRat(1, 1, fn, fd)
local t2n, t2d = mulRat(sn, sd, t1n, t1d)
local tn, td = subRat(1, 1, t2n, t2d)
local r1n,r1d,g1n,g1d,b1n,b1d
if index == 0 then
r1n,r1d,g1n,g1d,b1n,b1d = vn,vd,tn,td,pn,pd
elseif index == 1 then
r1n,r1d,g1n,g1d,b1n,b1d = qn,qd,vn,vd,pn,pd
elseif index == 2 then
r1n,r1d,g1n,g1d,b1n,b1d = pn,pd,vn,vd,tn,td
elseif index == 3 then
r1n,r1d,g1n,g1d,b1n,b1d = pn,pd,qn,qd,vn,vd
elseif index == 4 then
r1n,r1d,g1n,g1d,b1n,b1d = tn,td,pn,pd,vn,vd
else
r1n,r1d,g1n,g1d,b1n,b1d = vn,vd,pn,pd,qn,qd
end
local rn, rd = mulRat(r1n, r1d, 255, 1)
local gn, gd = mulRat(g1n, g1d, 255, 1)
local bn, bd = mulRat(b1n, b1d, 255, 1)
return rn/rd, gn/gd, bn/bd
end
function hsv(h,s,v,a)
assert(type(h) == "number" and type(s) == "number" and type(v) == "number" ,
"heart.hsv(h,s,v) values is not passed in as numbers")
--s = math.clamp(s,0,1)
--v = math.clamp(v,0,1)
a = a or 1
if s == 0 then
return v*255,v*255,v*255,a*255
end
h = h / 60 % 6
local index = math.floor(h)
local f = h - index
local p = v * ( 1 - s )
local q = v * ( 1 - s * f )
local t = v * ( 1 - s * ( 1 - f ) )
local r,g,b
if index == 0 then
r,g,b = v,t,p
elseif index == 1 then
r,g,b = q,v,p
elseif index == 2 then
r,g,b = p,v,t
elseif index == 3 then
r,g,b = p,q,v
elseif index == 4 then
r,g,b = t,p,v
else
r,g,b = v,p,q
end
return r*255,g*255,b*255,a*255
end
for i = 0, 1530 - 1 do
local r1, g1, b1 = hsvRational(i,1530,1,1,1,1)
local r2, g2, b2 = hsv(i / 4.25,1,1,1)
print("Index "..i)
print(r1, g1, b1)
print(r2, g2, b2)
print(
r1 == r2 and "" or "Red Diff",
g1 == g2 and "" or "Grenn Diff",
b1 == b2 and "" or "Blue Diff")
end
Lua
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