83 lines
2.0 KiB
Lua
83 lines
2.0 KiB
Lua
-- ostro_to8.lua : convert a color image to a BM16
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-- (160x200x16) thomson image using the Ostromoukhov's
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-- error diffusion algorithm.
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--
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-- Version: 02-jan-2017
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--
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-- Copyright 2016-2017 by Samuel Devulder
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--
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-- This program is free software; you can redistribute
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-- it and/or modify it under the terms of the GNU
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-- General Public License as published by the Free
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-- Software Foundation; version 2 of the License.
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-- See <http://www.gnu.org/licenses/>
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run('lib/thomson.lua')
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run('lib/ostromoukhov.lua')
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run('lib/color_reduction.lua')
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-- run('lib/zzz.lua')
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-- get screen size
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local screen_w, screen_h = getpicturesize()
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-- Converts thomson coordinates (0-159,0-199) into screen coordinates
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local function thom2screen(x,y)
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local i,j;
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if screen_w/screen_h < 1.6 then
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i = x*screen_h/200
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j = y*screen_h/200
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else
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i = x*screen_w/320
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j = y*screen_w/320
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end
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return math.floor(i*2), math.floor(j)
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end
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-- return the Color @(x,y) in normalized linear space (0-1)
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-- corresonding to the thomson screen (x in 0-319, y in 0-199)
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local function getLinearPixel(x,y)
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local x1,y1 = thom2screen(x,y)
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local x2,y2 = thom2screen(x+1,y+1)
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if x2==x1 then x2=x1+1 end
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if y2==y1 then y2=y1+1 end
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local p = Color:new(0,0,0);
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for j=y1,y2-1 do
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for i=x1,x2-1 do
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p:add(getLinearPictureColor(i,j))
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end
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end
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p:div((y2-y1)*(x2-x1)) --:floor()
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return p
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end
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local red = ColorReducer:new():analyzeWithDither(160,200,
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getLinearPixel,
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function(y)
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thomson.info("Collecting stats...",math.floor(y/2),"%")
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end)
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-- BM16 mode
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thomson.setBM16()
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-- define palette
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local palette = red:boostBorderColors():buildPalette(16)
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thomson.palette(0, palette)
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-- convert picture
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OstroDither:new(palette, 0)
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:dither(thomson.h,thomson.w,
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function(y,x) return getLinearPixel(x,y) end,
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function(y,x,c) thomson.pset(x,y,c) end,
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true,
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function(x) thomson.info("Converting...",math.floor(x*100/160),"%") end)
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-- refresh screen
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setpicturesize(320,200)
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thomson.updatescreen()
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finalizepicture()
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-- save picture
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thomson.savep()
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