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Add scripts to color-reduce pictures with constraints

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Scripts for various Thomson machines, Oric and ZX. All the hard work of
Samuel Devulder, with extensive research on color palette reduction
algorithms, lots of testing, research and debugging.

Thanks a lot!
This commit is contained in:
Adrien Destugues
2017-03-21 21:48:39 +01:00
parent 32b3996cb8
commit f4bfaeca89
18 changed files with 3274 additions and 0 deletions
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share/grafx2/scripts/samples_2.4/picture/thomson/bayer4_mo5.lua Normal file
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-- bayer4_mo5.lua : converts an image into TO7/70-MO5
-- mode for thomson machines (MO6,TO8,TO9,TO9+)
-- using special bayer matrix that fits well with
-- color clashes.
--
-- Version: 02-jan-2017
--
-- Copyright 2016-2017 by Samuel Devulder
--
-- This program is free software; you can redistribute
-- it and/or modify it under the terms of the GNU
-- General Public License as published by the Free
-- Software Foundation; version 2 of the License.
-- See <http://www.gnu.org/licenses/>
-- get screen size
local screen_w, screen_h = getpicturesize()
run("lib/thomson.lua")
run("lib/color.lua")
run("lib/bayer.lua")
-- Converts thomson coordinates (0-319,0-199) into screen coordinates
local function thom2screen(x,y)
local i,j;
if screen_w/screen_h < 1.6 then
i = x*screen_h/200
j = y*screen_h/200
else
i = x*screen_w/320
j = y*screen_w/320
end
return math.floor(i), math.floor(j)
end
-- return the pixel @(x,y) in normalized linear space (0-1)
-- corresonding to the thomson screen (x in 0-319, y in 0-199)
local function getLinearPixel(x,y)
local x1,y1 = thom2screen(x,y)
local x2,y2 = thom2screen(x+1,y+1)
if x2==x1 then x2=x1+1 end
if y2==y1 then y2=y1+1 end
local p,i,j = Color:new(0,0,0);
for i=x1,x2-1 do
for j=y1,y2-1 do
p:add(getLinearPictureColor(i,j))
end
end
p:div((y2-y1)*(x2-x1)*Color.ONE)
return p
end
local dither = bayer.norm(bayer.double(bayer.double({{1,2},{3,4}})))
local dx,dy=#dither,#dither[1]
-- get thomson palette pixel (linear, 0-1 range)
local linearPalette = {}
function linearPalette.get(i)
local p = linearPalette[i]
if not p then
local pal = thomson.palette(i-1)
local b=math.floor(pal/256)
local g=math.floor(pal/16)%16
local r=pal%16
p = Color:new(thomson.levels.linear[r+1],
thomson.levels.linear[g+1],
thomson.levels.linear[b+1]):div(Color.ONE)
linearPalette[i] = p
end
return p:clone()
end
-- distance between two colors
local distance = {}
function distance.between(c1,c2)
local k = c1..','..c2
local d = distance[k]
if false and not d then
d = linearPalette.get(c1):euclid_dist2(linearPalette.get(c2))
distance[k] = d
end
if not d then
local x = linearPalette.get(c1):sub(linearPalette.get(c2))
local c,c1,c2,c3=1.8,8,11,8
local f = function(c,x) return math.abs(x)*c end
d = f(c1,x.r)^c + f(c2,x.g)^c + f(c3,x.b)^c
distance[k] = d
end
return d
end
-- compute a set of best couples for a given histogram
local best_couple = {n=0}
function best_couple.get(h)
local k = (((h[1]or 0)*8+(h[2]or 0))*8+(h[3]or 0))*8+(h[4]or 0)
.. ',' .. (((h[5]or 0)*8+(h[6]or 0))*8+(h[7]or 0))*8+(h[8]or 0)
local best_found = best_couple[k]
if not best_found then
local dm=1000000
for i=1,15 do
for j=i+1,16 do
local d=0
for p,n in pairs(h) do
local d1,d2=distance.between(p,i),distance.between(p,j)
d = d + n*(d1<d2 and d1 or d2)
if d>dm then break; end
end
if d< dm then dm,best_found=d,{} end
if d<=dm then table.insert(best_found, {c1=i,c2=j}) end
end
end
if best_couple.n>10000 then
-- keep memory usage low
best_couple = {n=0, get=best_couple.get}
end
best_couple[k] = best_found
best_couple.n = best_couple.n+1
end
return best_found
end
-- TO7/70 MO5 mode
thomson.setMO5()
-- convert picture
local err1,err2 = {},{}
local coefs = {0,0.6,0}
for x=-1,320 do
err1[x] = Color:new(0,0,0)
err2[x] = Color:new(0,0,0)
end
for y = 0,199 do
err1,err2 = err2,err1
for x=-1,320 do err2[x]:mul(0) end
for x = 0,319,8 do
local h,q = {},{} -- histo, expected color
for z=x,x+7 do
local d=dither[1+(y%dx)][1+(z%dx)]
local p=getLinearPixel(z,y):add(err1[z])
local c=((p.r>d) and 1 or 0) +
((p.g>d) and 2 or 0) +
((p.b>d) and 4 or 0) + 1 -- theorical color
table.insert(q,c)
h[c] = (h[c] or 0)+1
end
local c1,c2
for c,_ in pairs(h) do
if c1==nil then c1=c
elseif c2==nil then c2=c
else c1=nil; break; end
end
if c1~=nil then
c2 = c2 or c1
else
-- get best possible couples of colors
local best_found = best_couple.get(h)
if #best_found==1 then
c1,c2 = best_found[1].c1,best_found[1].c2
else
-- keep the best of the best depending on max solvable color clashes
function clamp(v) return v<0 and -v or v>1 and v-1 or 0 end
local dm=10000000
for _,couple in ipairs(best_found) do
local d=0
for k=1,8 do
local q=q[k]
local p=distance.between(q,couple.c1)<distance.between(q,couple.c2) and couple.c1 or couple.c2
-- error between expected and best
local e=linearPalette.get(q):sub(linearPalette.get(p)):mul(coefs[1])
local z=getLinearPixel(x+k-1,y+1):add(e)
d = d + clamp(z.r) + clamp(z.g) + clamp(z.b)
end
if d<=dm then dm,c1,c2=d,couple.c1,couple.c2 end
end
end
end
-- thomson.pset(x,y,c1-1)
-- thomson.pset(x,y,-c2)
for k=0,7 do
local z=x+k
local q=q[k+1]
local p=distance.between(q,c1)<distance.between(q,c2) and c1 or c2
local d=linearPalette.get(q):sub(linearPalette.get(p))
err2[z]:add(d:mul(coefs[1]))
thomson.pset(z,y,p==c1 and c1-1 or -c2)
end
end
thomson.info("Converting...",math.floor(y/2),"%")
end
-- refresh screen
setpicturesize(320,200)
thomson.updatescreen()
finalizepicture()
-- save picture
do
local function exist(file)
local f=io.open(file,'rb')
if not f then return false else io.close(f); return true; end
end
local name,path = getfilename()
local mapname = string.gsub(name,"%.%w*$","") .. ".map"
local fullname = path .. '/' .. mapname
local ok = not exist(fullname)
if not ok then
selectbox("Ovr " .. mapname .. "?", "Yes", function() ok = true; end, "No", function() ok = false; end)
end
if ok then thomson.savep(fullname) end
end