cellcolourreducer.lua

-- cell colour reducer
-- jan'11, from Paulo Silva, with help from people from GrafX2 google group (DawnBringer, Adrien Destugues (PulkoMandy), and Yves Rizoud)
-- 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/>
w,h=getpicturesize()
xcell=8;ycell=8
function grayscaleindexed(c)
  r,g,b=getcolor(c)
  return math.floor((b*11+r*30+g*59)/100);end
celcnt={};for n=0,255,1 do celcnt[n+1]=0;end -- Arraycounter must have initial value
for y1=0,h-1,ycell do
  for x1=0,w-1,xcell do
    for i=0,255,1 do
      celcnt[i+1]=0;end
    for y2=0,ycell-1,1 do
      for x2=0,xcell-1,1 do
        x=x1+x2;y=y1+y2
        u=getpicturepixel(x,y)
        celcnt[u+1]=celcnt[u+1]+(1000*xcell*ycell)+math.random(0,950)
        end
      end
    ikattr=0;paattr=0;ikcnt=0;pacnt=0
    for i=0,255,1 do
      if ikcnt<celcnt[i+1] then ikcnt=celcnt[i+1];ikattr=i;end
      end
    celcnt[ikattr+1]=0
    for i=0,255,1 do
      if pacnt<celcnt[i+1] then pacnt=celcnt[i+1];paattr=i;end
      end
    if grayscaleindexed(ikattr)>grayscaleindexed(paattr) then tmpr=ikattr;ikattr=paattr;paattr=tmpr;end
    wmid=math.floor((grayscaleindexed(paattr)+grayscaleindexed(ikattr))/2)
    for y2=0,ycell-1,1 do
      for x2=0,xcell-1,1 do
        x=x1+x2;y=y1+y2
        u=getpicturepixel(x,y)
        if u==ikattr then
            idou=ikattr
          elseif u==paattr then
            idou=paattr
          else
            idou=ikattr
            if grayscaleindexed(u)>wmid then idou=paattr;end
          end
        putpicturepixel(x,y,idou)
        end
      end
    end
  end