grafx2 remove chess pattern method 2 lua

-- Remove dither pattern with horizontal approach - 1 pixel up and own supportedd- will add this for two in future---
-- Method 2 is different from method 1
--

-- This variant needs image to only use colors < 16


-- Determines which color should store the average of colors i and j.
-- Only works if i and j are different and both < 16.
function transp(i, j)
  if i < j then
    return i*15+j+15
  else
    return j*15+i+15
  end
end

-- Prepares the palette.
-- Thanks to DawnBringer for gamma expertise
-- Gamma factor should be set close to 1.6 for converting images designed on
-- very low resolutions, up to 2.2 on very high resolutions.
--
gamma = 1.8 -- gamma factor.
for i = 0, 15 do
  for j = i+1, 15 do
    r1, g1, b1 = getcolor(i);
    r2, g2, b2 = getcolor(j);
    r3 = math.pow(((math.pow(r1/255,gamma) + math.pow(r2/255,gamma)) / 2),(1/gamma))*255
    g3 = math.pow(((math.pow(g1/255,gamma) + math.pow(g2/255,gamma)) / 2),(1/gamma))*255
    b3 = math.pow(((math.pow(b1/255,gamma) + math.pow(b2/255,gamma)) / 2),(1/gamma))*255
    setcolor(transp(i,j), r3, g3, b3)
  end
end


-- Remove dither pattern with horizontal approach - 1 pixel up and own supportedd- will add  it for two in furue---

w, h = getpicturesize()

for y = 0, h - 1, 1 do

  for x = 0, w - 4, 1 do

get = getbackuppixel
put = putpicturepixel
c1 = get(x,y);
c2 = get(x+1,y);
c3 = get(x+2,y);
c4 = get(x+3,y);

if (c1 == c3) and (c2 == c4) and (c1 ~= c2) and (c2 ~= c3) and (get(x,y+1) ~= c1) and (get(x+1,y+1) ~= c2) and (get(x+2,y+1) ~= c3) and (get(x+3,y+1) ~= c4) and (get(x,y-1) ~= c1) and (get(x+1,y-1) ~= c2) and (get(x+2,y-1) ~= c3) and (get(x+3,y-1) ~= c4) then
  r1, g1, b1 = getcolor(c1);
  r2, g2, b2 = getcolor(c2);


  avgcol = transp(c1, c2)

  put(x, y, avgcol);
  put(x+1, y, avgcol);
  put(x+2, y, avgcol);
  put(x+3, y, avgcol);

-- expand on all 4 directions up --
    if (get(x,y+1) == c2) and (get(x+1,y+1) ~= c2) and (get(x-1,y+1) ~= c2) and ((get(x+1,y+1) == c1) or (get(x-1,y+1) == c1)) then
put(x, y+1, avgcol);
  end
  if (get(x+1,y+1) == c1) and (get(x+2,y+1) ~= c1) and (get(x,y+1) ~= c1) and ((get(x+2,y+1) == c2) or (get(x,y+1) == c2)) then
put(x+1, y+1, avgcol);
  end
  if (get(x+2,y+1) == c2) and (get(x+3,y+1) ~= c2) and (get(x+1,y+1) ~= c2) and ((get(x+3,y+1) == c1) or (get(x+1,y+1) == c1)) then
put(x+2, y+1, avgcol);
  end
  if (get(x+3,y+1) == c1) and  (get(x+4,y+1) ~= c1) and (get(x+2,y+1) ~= c1) and ((get(x+4,y+1) == c2) or (get(x+2,y+1) == c2)) then
put(x+3, y+1, avgcol);
  end
-- expand on all 4 directions down --
    if (get(x,y-1) == c2) and (get(x+1,y-1) ~= c2) and (get(x-1,y-1) ~= c2) and ((get(x+1,y-1) == c1) or (get(x-1,y-1) == c1)) then
put(x, y-1, avgcol);
  end
  if (get(x+1,y-1) == c1) and (get(x+2,y-1) ~= c1) and (get(x,y-1) ~= c1) and ((get(x+2,y-1) == c2) or (get(x,y-1) == c2)) then
put(x+1, y-1, avgcol);
  end
  if (get(x+2,y-1) == c2) and (get(x+3,y-1) ~= c2) and (get(x+1,y-1) ~= c2) and ((get(x+3,y-1) == c1) or (get(x+1,y-1) == c1)) then
put(x+2, y-1, avgcol);
  end
  if (get(x+3,y-1) == c1) and  (get(x+4,y-1) ~= c1) and (get(x+2,y-1) ~= c1) and ((get(x+4,y-1) == c2) or (get(x+2,y-1) == c2)) then
put(x+3, y-1, avgcol);
  end
end
  end
end

-- Remove left dither pattern with 4x1 vertical. Contains some important if then else conditions.--

w, h = getpicturesize()

for y = 0, h - 4, 1 do

  for x = 0, w - 1, 1 do

get = getbackuppixel
put = putpicturepixel
c1 = get(x,y);
c2 = get(x,y+1);
c3 = get(x,y+2);
c4 = get(x,y+3);

if (c1 == c3) and (c2 == c4) and  (c1 ~= c2) and (c2 ~= c3) and (get(x+1,y) ~= c1) and (get(x+1,y+1) ~= c2) and (get(x+1,y+2) ~= c3) and (get(x+1,y+3) ~= c4) and (get(x-1,y) ~= c1) and (get(x-1,y+1) ~= c2) and (get(x-1,y+2) ~= c3) and (get(x-1,y+3) ~= c4) and (get(x,y+4) ~=c4) and (get(x,y-1) ~=c1) then
  r1, g1, b1 = getcolor(c1);
  r2, g2, b2 = getcolor(c2);


  avgcol = transp(c1, c2)

  put(x, y, avgcol);
  put(x, y+1, avgcol);
  put(x, y+2, avgcol);
  put(x, y+3, avgcol);

-- expand on all 4 directions up --
  if (get(x+1,y) == c2) and (((get(x+1,y+1) ~= c2) and (get(x+1,y-1) == c1)) or ((get(x+1,y+1) == c1) and (get(x+1,y-1) ~= c2))) then
put(x+1, y, avgcol);
  end
  if (get(x+1,y+1) == c1) and (((get(x+1,y+2) ~= c1) and (get(x+1,y) == c2)) or ((get(x+1,y+2) == c2) and (get(x+1,y) ~= c1))) then
put(x+1, y+1, avgcol);
  end
  if (get(x+1,y+2) == c2) and (((get(x+1,y+3) ~= c2) and (get(x+1,y+1) == c1)) or ((get(x+1,y+3) == c1) and (get(x+1,y+1) ~= c2))) then
put(x+1, y+2, avgcol);
  end
  if (get(x+1,y+3) == c1) and  (((get(x+1,y+4) ~= c1) and (get(x+1,y+2) == c2)) or ((get(x+1,y+4) == c2) and (get(x+1,y+2) ~= c1))) then
put(x+1, y+3, avgcol);
  end
-- expand on all 4 directions down --
  if (get(x-1,y) == c2) and (((get(x-1,y+1) ~= c2) and (get(x-1,y-1) == c1)) or ((get(x-1,y+1) == c1) and (get(x-1,y-1) ~= c2))) then
put(x-1, y, avgcol);
  end
  if (get(x-1,y+1) == c1) and (((get(x-1,y+2) ~= c1) and (get(x-1,y) == c2)) or ((get(x-1,y+2) == c2) and (get(x-1,y) ~= c1))) then
put(x-1, y+1, avgcol);
  end
  if (get(x-1,y+2) == c2) and (((get(x-1,y+3) ~= c2) and (get(x-1,y+1) == c1)) or ((get(x-1,y+3) == c1) and (get(x-1,y+1) ~= c2))) then
put(x-1, y+2, avgcol);
  end
  if (get(x-1,y+3) == c1) and  (((get(x-1,y+4) ~= c1) and (get(x-1,y+2) == c2)) or ((get(x-1,y+4) == c2) and (get(x-1,y+2) ~= c1))) then
put(x-1, y+3, avgcol);
  end
end
  end
end