Pixel Joint Forum: How do i remove chess patterns from pixel art??

Message

-- Remove dither pattern
--
--

-- 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

w, h = getpicturesize()

for i = 0, 15 do
  for j = i+1, 15 do
    r1, g1, b1 = getcolor(i);
    r2, g2, b2 = getcolor(j);
    
    setcolor(transp(i,j), (r1+r2) / 2, (g1+g2) / 2, (b1+b2) / 2)
  end
end

for y = 0, h - 2, 1 do

  for x = 0, w - 2, 1 do
    
    -- Pixels:
    -- 
    -- c1 c2
    -- c3 c4
    --
    
    c1 = getbackuppixel(x,y);
    c2 = getbackuppixel(x+1,y);
    
    if (c1 ~= c2) and (c1<16) and (c2<16) then
      
      c3 = getbackuppixel(x,y+1);
      c4 = getbackuppixel(x+1,y+1);
      
      if (c1 == c4) and (c2 == c3) then
        avgcol = transp(c1, c2)
        
        putpicturepixel(x, y, avgcol);
        putpicturepixel(x+1, y, avgcol);
        putpicturepixel(x, y+1, avgcol);
        putpicturepixel(x+1, y+1, avgcol);
        
        -- expand on all 4 directions
        if (getbackuppixel(x-1,y) == c2) then
          putpicturepixel(x-1, y, avgcol);
        end
        if (getbackuppixel(x,y-1) == c2) then
          putpicturepixel(x, y-1, avgcol);
        end
        if (getbackuppixel(x+1,y-1) == c1) then
          putpicturepixel(x+1, y-1, avgcol);
        end
        if (getbackuppixel(x+2,y) == c1) then
          putpicturepixel(x+2, y, avgcol);
        end
        if (getbackuppixel(x+2,y+1) == c2) then
          putpicturepixel(x+2, y+1, avgcol);
        end
        if (getbackuppixel(x+1,y+2) == c2) then
          putpicturepixel(x+1, y+2, avgcol);
        end
        if (getbackuppixel(x,y+2) == c1) then
          putpicturepixel(x, y+2, avgcol);
        end
        if (getbackuppixel(x-1,y+1) == c1) then
          putpicturepixel(x-1, y+1, avgcol);
        end
      end
    end
  end
end

Author	Message
bluedxca93 Commander Joined: 27 February 2016 Online Status: Offline Posts: 104	Topic: How do i remove chess patterns from pixel art?? Posted: 09 January 2014 at 11:08pm
	Hello, Some old icons or bitmaps are using chess patterns for dithering. is there a way to remove them ??? Have tought that when we have p. ex a b a b a b as pixels from one 1px height image. Is there an program who can convert this directly to (delta (a+b)) (delta ((a+b))... Something like this could quickly remove chess patterns including few more colors to the image. It doesn't need to be precise at edges or lines like these \ . Has anyone an idea. I don't mean the gimp or photoshop transparency patterns.! Blurring or down- upscale doesn't help. regards bluedxca93
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yrizoud Commander Joined: 03 May 2021 Location: France Online Status: Offline Posts: 343	Posted: 10 January 2014 at 4:43am
	If you resize to exactly 50% with algorithm "Bilinear filtering" or "Trilinear filtering", it should turn these patterns into flat color which is average of the two colors. You do lose pixel details, however. Or you may want to try write a script in Grafx2 that examines all 2x2 squares of an image, and if it sees the "grid" pattern, replace all 4 pixels by the average color. It is still imperfect (won't process the "edges" of these patterns), but it can already do a lot of the work.
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bluedxca93 Commander Joined: 27 February 2016 Online Status: Offline Posts: 104	Posted: 10 January 2014 at 6:42am
	Hi, have tought how an computer program might be able to delete these patterns. (see graphic) For one chess pattern: 1) use the 2x2 method an intodruce an new color which isn't in the image palette already. i would name it c. 2) change c+a+b+a+b and c+b+a+b+a in horizontal and vertical direction to c+c+c+c+c 3) change c+a+b+a and c+b+a+b in horizontal and vertical direction to c+c+c+c 4) change c+a+b and c+b+ain horizontal and vertical direction to c+c+c 5) change c+a and c+b in horizontal and vertical direction to c+c 6) set c to delta a+c. The steps 4+5 are a bit risky. However an algorith like this would be better than downscaling. It does some errors, but the chess pattern would begone completly. Some upscaling algorithms or rot sprite have huge problems with these. Unfortunatly i don't know how to use grafx2 or how to write an standalone pixel shader based app. Edited by bluedxca93 - 10 January 2014 at 6:43am
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yrizoud Commander Joined: 03 May 2021 Location: France Online Status: Offline Posts: 343	Posted: 10 January 2014 at 11:58am
	I've just made a script for Grafx2, it auto-detects patterns by the presence of 2x2 block with any colors in pattern: OX XO It makes the average, and then tries to expand on the 8 surrounding pixels. Here is the result for your icon: As you can see, it can mistakenly affect small pixels like the P and N letters. -- Remove dither pattern w, h = getbrushsize() for y = 0, h - 2, 1 do for x = 0, w - 2, 1 do c1 = getbrushbackuppixel(x,y); c2 = getbrushbackuppixel(x+1,y); c3 = getbrushbackuppixel(x,y+1); c4 = getbrushbackuppixel(x+1,y+1); if (c1 == c4) and (c2 == c3) then r1, g1, b1 = getcolor(c1); r2, g2, b2 = getcolor(c2); avgcol = matchcolor((r1+r2)/2, (g1+g2)/2, (b1+b2)/2) putbrushpixel(x, y, avgcol); putbrushpixel(x+1, y, avgcol); putbrushpixel(x, y+1, avgcol); putbrushpixel(x+1, y+1, avgcol); -- expand on all 4 directions if (getbrushbackuppixel(x-1,y) == c2) then putbrushpixel(x-1, y, avgcol); end if (getbrushbackuppixel(x,y-1) == c2) then putbrushpixel(x, y-1, avgcol); end if (getbrushbackuppixel(x+1,y-1) == c1) then putbrushpixel(x+1, y-1, avgcol); end if (getbrushbackuppixel(x+2,y) == c1) then putbrushpixel(x+2, y, avgcol); end if (getbrushbackuppixel(x+2,y+1) == c2) then putbrushpixel(x+2, y+1, avgcol); end if (getbrushbackuppixel(x+1,y+2) == c2) then putbrushpixel(x+1, y+2, avgcol); end if (getbrushbackuppixel(x,y+2) == c1) then putbrushpixel(x, y+2, avgcol); end if (getbrushbackuppixel(x-1,y+1) == c1) then putbrushpixel(x-1, y+1, avgcol); end end end end Edited by yrizoud - 10 January 2014 at 12:00pm
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bluedxca93 Commander Joined: 27 February 2016 Online Status: Offline Posts: 104	Posted: 11 January 2014 at 12:55am
	Hi, Good thing It works ! The bad thing is, that i don't know how to apply it without copy the image before in some strange selct/brush image buffer. But that isn`t that important. I think i understand now how the scripting thing works. If i can make an better script I will post it. The average colors it produces are really nice . It is fast and produce nearly perfect ouput. regards bluedxca93.
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yrizoud Commander Joined: 03 May 2021 Location: France Online Status: Offline Posts: 343	Posted: 11 January 2014 at 3:14am
	In the script you can replace "brush" by "picture" everywhere; I used the brush because I found it easier to compare with the original. Also when the script determines the average color, there's no guarantee the current image palette has a very good candidate. If you're converting 16-color icons, I could make it first fill palette entries >16 with the color combinations. Can you post one or two other sample images I can test with ?
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bluedxca93 Commander Joined: 27 February 2016 Online Status: Offline Posts: 104	Posted: 11 January 2014 at 6:51am
	hi, on my grafx2 version getbackuppicturepixel doesn't work. How do i intodruce the new colors in the palette? Have tested an 4x1 pattern which works well on images like these: http://www.goodolddays.net/game/id,416/lang,de/%C3%96kolopoly.html I would try to improve it. regards bluedxca93 Edited by bluedxca93 - 11 January 2014 at 6:56am
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bluedxca93 Commander Joined: 27 February 2016 Online Status: Offline Posts: 104	Posted: 11 January 2014 at 7:31am
	Have found the bug: getbackuppicturepixel is named getbackuppixel in reality. Here my 1x4 script ( only at the moment, I will add y correction). I also think that i could improve your 2x2 script. This script does alrady a lot on big pictures. Please tell me how to add the new colors to the palette. -- Remove dither pattern with 1x4 horzontal method and slight 1px vertcal support.-- w, h = getpicturesize() for y = 0, h - 1, 1 do for x = 0, w - 4, 1 do c1 = getbackuppixel(x,y); c2 = getbackuppixel(x+1,y); c3 = getbackuppixel(x+2,y); c4 = getbackuppixel(x+3,y); if (c1 == c3) and (c2 == c4) then r1, g1, b1 = getcolor(c1); r2, g2, b2 = getcolor(c2); avgcol = matchcolor((r1+r2)/2, (g1+g2)/2, (b1+b2)/2) putpicturepixel(x, y, avgcol); putpicturepixel(x+1, y, avgcol); putpicturepixel(x+2, y, avgcol); putpicturepixel(x+3, y, avgcol); -- expand on all 4 directions up -- if (getbackuppixel(x,y+1) == c2) and (getbackuppixel(x+1,y+1) == c1) then putpicturepixel(x, y+1, avgcol); end if (getbackuppixel(x+1,y+1) == c1) and (getbackuppixel(x+2,y+1) == c2) then putpicturepixel(x+1, y+1, avgcol); end if (getbackuppixel(x+2,y+1) == c2) and (getbackuppixel(x+3,y+1) == c1) then putpicturepixel(x+2, y+1, avgcol); end if (getbackuppixel(x+3,y+1) == c1) and (getbackuppixel(x+4,y+1) == c2) then putpicturepixel(x+3, y+1, avgcol); end -- expand on all 4 directions down -- if (getbackuppixel(x,y-1) == c2) and (getbackuppixel(x+1,y-1) == c1) then putpicturepixel(x, y-1, avgcol); end if (getbackuppixel(x+1,y-1) == c1) and (getbackuppixel(x+2,y-1) == c2) then putpicturepixel(x+1, y-1, avgcol); end if (getbackuppixel(x+2,y-1) == c2) and (getbackuppixel(x+3,y-1) == c1) then putpicturepixel(x+2, y-1, avgcol); end if (getbackuppixel(x+3,y-1) == c1) and (getbackuppixel(x+4,y-1) == c2) then putpicturepixel(x+3, y-1, avgcol); end end end end Edited by bluedxca93 - 11 January 2014 at 8:25am
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yrizoud Commander Joined: 03 May 2021 Location: France Online Status: Offline Posts: 343	Posted: 11 January 2014 at 11:45am
	Sorry about the syntax :/ Here's a script that affects the image directly. It's specialized to work on 16-color images such as those screenshots from Hi-res VGA images (640x400 16col), so before running script you should first open Palette menu and choose Reduce - to 16. -- Remove dither pattern -- -- -- 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 i15+j+15 else return j15+i+15 end end w, h = getpicturesize() for i = 0, 15 do for j = i+1, 15 do r1, g1, b1 = getcolor(i); r2, g2, b2 = getcolor(j); setcolor(transp(i,j), (r1+r2) / 2, (g1+g2) / 2, (b1+b2) / 2) end end for y = 0, h - 2, 1 do for x = 0, w - 2, 1 do -- Pixels: -- -- c1 c2 -- c3 c4 -- c1 = getbackuppixel(x,y); c2 = getbackuppixel(x+1,y); if (c1 ~= c2) and (c1<16) and (c2<16) then c3 = getbackuppixel(x,y+1); c4 = getbackuppixel(x+1,y+1); if (c1 == c4) and (c2 == c3) then avgcol = transp(c1, c2) putpicturepixel(x, y, avgcol); putpicturepixel(x+1, y, avgcol); putpicturepixel(x, y+1, avgcol); putpicturepixel(x+1, y+1, avgcol); -- expand on all 4 directions if (getbackuppixel(x-1,y) == c2) then putpicturepixel(x-1, y, avgcol); end if (getbackuppixel(x,y-1) == c2) then putpicturepixel(x, y-1, avgcol); end if (getbackuppixel(x+1,y-1) == c1) then putpicturepixel(x+1, y-1, avgcol); end if (getbackuppixel(x+2,y) == c1) then putpicturepixel(x+2, y, avgcol); end if (getbackuppixel(x+2,y+1) == c2) then putpicturepixel(x+2, y+1, avgcol); end if (getbackuppixel(x+1,y+2) == c2) then putpicturepixel(x+1, y+2, avgcol); end if (getbackuppixel(x,y+2) == c1) then putpicturepixel(x, y+2, avgcol); end if (getbackuppixel(x-1,y+1) == c1) then putpicturepixel(x-1, y+1, avgcol); end end end end end
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bluedxca93 Commander Joined: 27 February 2016 Online Status: Offline Posts: 104	Posted: 14 January 2014 at 12:10am
	Hi, Have now written an nearly perfect chess pattern remover =) . It is based on some complex predefined patterns. It works well, and i would still improve the algorithm a bit. It produces different output when you rotate the image. . I have tried with 2x2 approach like yours but this causes some problems with letters like N in bitmap fonts and some other things. Isn't it possible to add the missing the colors to the palette and then using avgcolor? I think i can post this in the forum as text, but how do i attach files for biiger scripts. ?? -- Remove dither pattern with horizontal approach - 1 pixel up and own supportedd- will add this for two in future--- w, h = getpicturesize() for y = 0, h - 1, 1 do for x = 0, w - 4, 1 do c1 = getbackuppixel(x,y); c2 = getbackuppixel(x+1,y); c3 = getbackuppixel(x+2,y); c4 = getbackuppixel(x+3,y); if (c1 == c3) and (c2 == c4) and (c1 ~= c2) and (c2 ~= c3) and (getbackuppixel(x,y+1) ~= c1) and (getbackuppixel(x+2,y+1) ~= c1) and (getbackuppixel(x,y-1) ~= c1) and (getbackuppixel(x+2,y-1) ~= c1) then r1, g1, b1 = getcolor(c1); r2, g2, b2 = getcolor(c2); avgcol = matchcolor((r1+r2)/2, (g1+g2)/2, (b1+b2)/2) putpicturepixel(x, y, avgcol); putpicturepixel(x+1, y, avgcol); putpicturepixel(x+2, y, avgcol); putpicturepixel(x+3, y, avgcol); -- expand on all 4 directions up -- if (getbackuppixel(x,y+1) == c2) and (getbackuppixel(x+1,y+1) ~= c2) and (getbackuppixel(x-1,y+1) ~= c2) and ((getbackuppixel(x+1,y+1) == c1) or (getbackuppixel(x-1,y+1) == c1)) then putpicturepixel(x, y+1, avgcol); end if (getbackuppixel(x+1,y+1) == c1) and (getbackuppixel(x+2,y+1) ~= c1) and (getbackuppixel(x,y+1) ~= c1) and ((getbackuppixel(x+2,y+1) == c2) or (getbackuppixel(x,y+1) == c2)) then putpicturepixel(x+1, y+1, avgcol); end if (getbackuppixel(x+2,y+1) == c2) and (getbackuppixel(x+3,y+1) ~= c2) and (getbackuppixel(x+1,y+1) ~= c2) and ((getbackuppixel(x+3,y+1) == c1) or (getbackuppixel(x+1,y+1) == c1)) then putpicturepixel(x+2, y+1, avgcol); end if (getbackuppixel(x+3,y+1) == c1) and (getbackuppixel(x+4,y+1) ~= c1) and (getbackuppixel(x+2,y+1) ~= c1) and ((getbackuppixel(x+4,y+1) == c2) or (getbackuppixel(x+2,y+1) == c2)) then putpicturepixel(x+3, y+1, avgcol); end -- expand on all 4 directions down -- if (getbackuppixel(x,y-1) == c2) and (getbackuppixel(x+1,y-1) ~= c2) and (getbackuppixel(x-1,y-1) ~= c2) and ((getbackuppixel(x+1,y-1) == c1) or (getbackuppixel(x-1,y-1) == c1)) then putpicturepixel(x, y-1, avgcol); end if (getbackuppixel(x+1,y-1) == c1) and (getbackuppixel(x+2,y-1) ~= c1) and (getbackuppixel(x,y-1) ~= c1) and ((getbackuppixel(x+2,y-1) == c2) or (getbackuppixel(x,y-1) == c2)) then putpicturepixel(x+1, y-1, avgcol); end if (getbackuppixel(x+2,y-1) == c2) and (getbackuppixel(x+3,y-1) ~= c2) and (getbackuppixel(x+1,y-1) ~= c2) and ((getbackuppixel(x+3,y-1) == c1) or (getbackuppixel(x+1,y-1) == c1)) then putpicturepixel(x+2, y-1, avgcol); end if (getbackuppixel(x+3,y-1) == c1) and (getbackuppixel(x+4,y-1) ~= c1) and (getbackuppixel(x+2,y-1) ~= c1) and ((getbackuppixel(x+4,y-1) == c2) or (getbackuppixel(x+2,y-1) == c2)) then putpicturepixel(x+3, y-1, avgcol); end end end end -- Remove left dither pattern with 4x1 vertical. Contains some important if then else conditions, so that it won't progress non chess patterns.-- w, h = getpicturesize() for y = 0, h - 4, 1 do for x = 0, w - 1, 1 do c1 = getbackuppixel(x,y); c2 = getbackuppixel(x,y+1); c3 = getbackuppixel(x,y+2); c4 = getbackuppixel(x,y+3); if (c1 == c3) and (c2 == c4) and (c1 ~= c2) and (c2 ~= c3) and (getbackuppixel(x+1,y) ~= c1) and (getbackuppixel(x+1,y+1) ~= c2) and (getbackuppixel(x+1,y+2) ~= c3) and (getbackuppixel(x+1,y+3) ~= c4) and (getbackuppixel(x-1,y) ~= c1) and (getbackuppixel(x-1,y+1) ~= c2) and (getbackuppixel(x-1,y+2) ~= c3) and (getbackuppixel(x-1,y+3) ~= c4) and (getbackuppixel(x,y+4) ~=c4) and (getbackuppixel(x,y-1) ~=c1) then r1, g1, b1 = getcolor(c1); r2, g2, b2 = getcolor(c2); avgcol = matchcolor((r1+r2)/2, (g1+g2)/2, (b1+b2)/2) putpicturepixel(x, y, avgcol); putpicturepixel(x, y+1, avgcol); putpicturepixel(x, y+2, avgcol); putpicturepixel(x, y+3, avgcol); -- expand on all 4 directions up -- if (getbackuppixel(x+1,y) == c2) and (getbackuppixel(x+1,y+1) == c1) then putpicturepixel(x+1, y, avgcol); end if (getbackuppixel(x+1,y+1) == c1) and (getbackuppixel(x+1,y+2) == c2) then putpicturepixel(x+1, y+1, avgcol); end if (getbackuppixel(x+1,y+2) == c2) and (getbackuppixel(x+1,y+3) == c1) then putpicturepixel(x+1, y+2, avgcol); end if (getbackuppixel(x+1,y+3) == c1) and (getbackuppixel(x+1,y+4) == c2) then putpicturepixel(x+1, y+3, avgcol); end -- expand on all 4 directions down -- if (getbackuppixel(x-1,y) == c2) and (getbackuppixel(x-1,y+1) == c1) then putpicturepixel(x-1, y, avgcol); end if (getbackuppixel(x-1,y+1) == c1) and (getbackuppixel(x-1,y+2) == c2) then putpicturepixel(x-1, y+1, avgcol); end if (getbackuppixel(x-1,y+2) == c2) and (getbackuppixel(x-1,y+3) == c1) then putpicturepixel(x-1, y+2, avgcol); end if (getbackuppixel(x-1,y+3) == c1) and (getbackuppixel(x-1,y+4) == c2) then putpicturepixel(x-1, y+3, avgcol); end end end end
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DawnBringer Commander Joined: 11 August 2024 Online Status: Offline Posts: 568	Posted: 14 January 2014 at 1:43am
	A tip: You can assign a function to a "variable", like gp = getbackuppixel then use gp(x,y) instead. This will shorten the code and make it more dynamic as you can easily reassign equivalent brush functions.
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neota Commander Joined: 27 November 2018 Online Status: Offline Posts: 158	Posted: 14 January 2014 at 5:02am
	I think i can post this in the forum as text, but how do i attach files for biiger scripts. ?? Pastebin it instead, and give us the link. http://bpaste.net is my preferred pastebin-like service, personally. If you take the time to select the language being used, you also get syntax highlighting, which is very useful if you expect others to read your code.
	absolutely.
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yrizoud Commander Joined: 03 May 2021 Location: France Online Status: Offline Posts: 343	Posted: 14 January 2014 at 11:17am
	Here's your script where I added the palette modification. I improved the computation of "average" by taking into account gamma correction, thanks to DawnBringer for quick answer to my gamma questions :) http://bpaste.net/show/y0dTuTVRXdCwDhGwfa0c/ An example of result (animation before/after): Edited by yrizoud - 14 January 2014 at 11:17am
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Different55 Seaman Joined: 22 July 2019 Online Status: Offline Posts: 13	Posted: 14 January 2014 at 2:42pm
	In some places it ends up blurring vertical lines, most noticeably in the tower in the left and and the train car in the right. In other places it turns light, 1px wide lines into dashed lines, like in the bottom right corner. It's averaging the color of the pixels at that white spot in the trees at the very left side. Overall it's looking pretty good.
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bluedxca93 Commander Joined: 27 February 2016 Online Status: Offline Posts: 104	Posted: 14 January 2014 at 11:19pm
	Yes, the vertical line algorith is really only average . But i have some ideas to fix this. I would also try to set an variable for getbackuppixel 'cause the lines are sometimes longer than my screen resolutions, so that i don't see the line breaks anymore XD. It works amazingly well on small 32x32 bitmaps too. Patterns like these: ababab could still be affected wrongly sometimes.But not often!. As you can see the w and m pattern are not affected by the algorithm. yirzoud/DawnBringer thanks for your help with the color palettes issues. And also thaks to neota for the pastebin tip. Can i use the linux text / / highlighting in grafx2 scripts? regards bluedxca93
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neota Commander Joined: 27 November 2018 Online Status: Offline Posts: 158	Posted: 14 January 2014 at 11:37pm
	^ If you use a programmers editor -- for example, I use Geany, and also Editra.. then you will get syntax highlighting for most common languages (that typically includes Lua). I am guessing at what you meant by Can i use the linux text / / highlighting in grafx2 scripts? .. I think you were trying to ask about syntax highlighting in your editor. If you are talking about C-style block comments instead, see this information about Lua block comments (the relevant info is at the bottom of the page). In either case, these things are not especially associated with Linux; You can do them on any operating system. Edited by neota - 14 January 2014 at 11:53pm
	absolutely.
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bluedxca93 Commander Joined: 27 February 2016 Online Status: Offline Posts: 104	Posted: 15 January 2014 at 4:21am
	Yeah, you are right. I forget sometimes that you can do compile programs or run scripts with windows too. After w2k i didn't use it very much (except some programs inside wine) . I use the simple texteditor gedit and sometimes meld for comparision of texts. And thanks for the link. `ve noticed, that the current algorithm has problems with 2 color bitmaps.
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bluedxca93 Commander Joined: 27 February 2016 Online Status: Offline Posts: 104	Posted: 17 January 2014 at 6:14am
	Method 1 : http://pastebin.com/72ECfysR Method 2 : http://pastebin.com/UBJuh38x Both Methods do remove chess pattern. However the result will differ. I can't say which method is better, it depends on the image size the art of the image and other things. WARNING: It won't work on Black/White images very well. Those images would require an entire different algorithm logic. Processing p.ex 640x480 16 color images may still take some time but i think that black and white images would take much more time. ( The filter logic would be really complex for 2 color images.).
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DawnBringer Commander Joined: 11 August 2024 Online Status: Offline Posts: 568	Posted: 22 January 2014 at 2:47am
	Btw. Dividing and multiplying with 255 is redundant in the gamma-correction.
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bluedxca93 Commander Joined: 27 February 2016 Online Status: Offline Posts: 104	Posted: 22 January 2014 at 4:06am
	That is true, but i didn't really looked at this part of the lua script code. The code works a bit slow, but not too slow =). I Have also tried to implement something like this script whith imagemagick but it seems to be impossible.
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neota Commander Joined: 27 November 2018 Online Status: Offline Posts: 158	Posted: 22 January 2014 at 5:59am
	You might be able to implement it using GMIC instead: http://gmic.sourceforge.net/
	absolutely.
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yrizoud Commander Joined: 03 May 2021 Location: France Online Status: Offline Posts: 343	Posted: 22 January 2014 at 8:02am
	Btw. Dividing and multiplying with 255 is redundant in the gamma-correction. That is true, but i didn't really looked at this part of the lua script code. This critic was directed at me :) I'm really bad at detecting when f(xN) == f(x)N To my defense, this part is called only 136 times, no matter the image size. Bluedxca93 : Do you have a lot of images to convert ? So far you seem to have spent a lot of time on this.
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bluedxca93 Commander Joined: 27 February 2016 Online Status: Offline Posts: 104	Posted: 23 January 2014 at 6:58am
	136 times is not much. Gmic is to complicated for me. Have tried now gluas. I think i will get an working version soon. Perhaps this will also improve the grafx2 script. Not really, i want to upscale some 32x32 or 48x48 pixmaps with chess patterns. And it takes some time to edit every bitmap before upscaling.
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yrizoud Commander Joined: 03 May 2021 Location: France Online Status: Offline Posts: 343	Posted: 23 January 2014 at 7:06am
	For mass conversion, I'd use : imagemagick for mass conversion into 16 colors (single command line) In grafx2: Assign a keyboard shortcut to the script, like Alt-R for example. For each file: F3 (select file) enter Alt-R Shift F2 Repeat
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