OC-KittenOS/code/libs/braille.lua

-- Copyright (C) 2018-2021 by KittenOS NEO contributors
--
-- Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted.
--
-- THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
-- THIS SOFTWARE.

-- Braille Converter & NeoUX component
-- While the Neoux part isn't OS-independent,
--  the converter itself is. Enjoy.

-- Braille Neoux Component Callbacks :
--  selectable (boolean)
--  key(window, update, a, c, d, keyFlags)
--  touch(window, update, x, y, button)
--  drag(window, update, x, y, button)
--  drop(window, update, x, y, button)
--  scroll(window, update, x, y, button)
--  clipboard(window, update, contents)
--  get(window, x, y, bg, fg, selected) -> r,g,b (REQUIRED)
-- REMINDER:
-- 03
-- 14
-- 25
-- 67
local function dotDist(ra, ga, ba, rb, gb, bb)
 local dR, dG, dB = math.abs(ra - rb)^2, math.abs(ga - gb)^2, math.abs(ba - bb)^2
 return (dR * 0.2126) + (dG * 0.7152) + (dB * 0.0722)
end
local function ditherResult(pos, pos2, luma)
 local res = false
 if luma >= 217 then
  res = true
 elseif luma >= 158 then
  res = not pos2
 elseif luma >= 96 then
  res = pos
 elseif luma >= 32 then
  res = pos2
 end
 return res
end
local function dotGet(p, ra, ga, ba, rb, gb, bb, rc, gc, bc, pos, pos2, col)
 if not col then
  -- Use our own magic
  local luma = (ra * 0.299) + (ga * 0.587) + (ba * 0.114)
  return (ditherResult(pos, pos2, luma) and p) or 0
 end
 local distA = dotDist(ra, ga, ba, rb, gb, bb)
 local distB = dotDist(ra, ga, ba, rc, gc, bc)
 local distAB = dotDist(rb, gb, bb, rc, gc, bc)
 local distC = dotDist(ra, ga, ba, (rb + rc) / 2, (gb + gc) / 2, (bb + bc) / 2)
 if (distC / 2) < math.min(distA, distB) then
  return (ditherResult(pos, pos2, (distA / math.max(distA, distB, 0.1)) * 255) and p) or 0
 end
 return ((distB < distA) and p) or 0
end
local function cTransform(core)
 return function (window, update, x, y, xI, yI, blah)
  x = (x * 2) + math.ceil(xI - 0.5)
  y = (y * 4) + math.ceil((yI - 0.25) * 4)
  core(window, update, x, y, blah)
 end
end
local function colourize(mark, ...)
 local t = {...}
 local bCR = 0
 local bCG = 0
 local bCB = 0
 if not mark then
  local nLuma = -1
  for i = 1, #t do
   local luma = (t[i][1] * 0.299) + (t[i][2] * 0.587) + (t[i][3] * 0.114)
   if luma > nLuma then
    bCR, bCG, bCB = table.unpack(t[i])
    nLuma = luma
   end
  end
  return bCR, bCG, bCB
 else
  local bCTS = math.huge
  for i = 1, #t do
   local ts = -dotDist(mark[1], mark[2], mark[3], table.unpack(t[i]))
   if ts < bCTS then
    bCR = t[i][1]
    bCG = t[i][2]
    bCB = t[i][3]
    bCTS = ts
   end
  end
 end
 return bCR, bCG, bCB
end
local function packRGB(r, g, b)
 return (r * 65536) + (g * 256) + b
end
-- span is a NeoUX-like span function (x, y, str, bg, fg)
-- x, y are character-cell start coordinates for this.
-- w is character-cell count.
-- colour is nil to disable colour,
-- otherwise the colour-change threshold (best 0)
-- get is a function r,g,b = get(xo, yo)
-- NOTE: xo/yo are 0-based!
local function calcLine(x, y, w, span, get, colour)
 local str = ""
 -- *g* : actual colour com.
 -- *g  : RGB mirror of colour
 local bgR, bgG, bgB = 0, 0, 0
 local fgR, fgG, fgB = 255, 255, 255
 local bg = 0
 local fg = 0xFFFFFF
 local ca = 0
 for p = 1, w do
  local i = 0x2800
  local xb = (p - 1) * 2
  local dot0R, dot0G, dot0B = get(xb + 0, 0)
  local dot1R, dot1G, dot1B = get(xb + 0, 1)
  local dot2R, dot2G, dot2B = get(xb + 0, 2)
  local dot3R, dot3G, dot3B = get(xb + 1, 0)
  local dot4R, dot4G, dot4B = get(xb + 1, 1)
  local dot5R, dot5G, dot5B = get(xb + 1, 2)
  local dot6R, dot6G, dot6B = get(xb + 0, 3)
  local dot7R, dot7G, dot7B = get(xb + 1, 3)
  if colour then
   local obgR, obgG, obgB = colourize(nil,
    {dot0R, dot0G, dot0B},
    {dot1R, dot1G, dot1B},
    {dot2R, dot2G, dot2B},
    {dot3R, dot3G, dot3B},
    {dot4R, dot4G, dot4B},
    {dot5R, dot5G, dot5B},
    {dot6R, dot6G, dot6B},
    {dot7R, dot7G, dot7B}
   )
   local ofgR, ofgG, ofgB = colourize({obgR, obgG, obgB},
    {dot0R, dot0G, dot0B},
    {dot1R, dot1G, dot1B},
    {dot2R, dot2G, dot2B},
    {dot3R, dot3G, dot3B},
    {dot4R, dot4G, dot4B},
    {dot5R, dot5G, dot5B},
    {dot6R, dot6G, dot6B},
    {dot7R, dot7G, dot7B}
   )
   if ((dotDist(obgR, obgG, obgB, bgR, bgG, bgB) > colour) and
      (dotDist(obgR, obgG, obgB, fgR, fgG, fgB) > colour)) or
      ((dotDist(ofgR, ofgG, ofgB, bgR, bgG, bgB) > colour) and
      (dotDist(ofgR, ofgG, ofgB, fgR, fgG, fgB) > colour)) then
    if ca ~= 0 then
     span(x, y, str, bg, fg)
     str = ""
    end
    x = x + ca
    ca = 0
    bg = packRGB(obgR, obgG, obgB)
    fg = packRGB(ofgR, ofgG, ofgB)
    bgR, bgG, bgB = obgR, obgG, obgB
    fgR, fgG, fgB = ofgR, ofgG, ofgB
   end
  end
  i = i + dotGet(1, dot0R, dot0G, dot0B, bgR, bgG, bgB, fgR, fgG, fgB, true, false, colour)
  i = i + dotGet(2, dot1R, dot1G, dot1B, bgR, bgG, bgB, fgR, fgG, fgB, false, false, colour)
  i = i + dotGet(4, dot2R, dot2G, dot2B, bgR, bgG, bgB, fgR, fgG, fgB, true, false, colour)
  i = i + dotGet(8, dot3R, dot3G, dot3B, bgR, bgG, bgB, fgR, fgG, fgB, false, false, colour)
  i = i + dotGet(16, dot4R, dot4G, dot4B, bgR, bgG, bgB, fgR, fgG, fgB, true, true, colour)
  i = i + dotGet(32, dot5R, dot5G, dot5B, bgR, bgG, bgB, fgR, fgG, fgB, false, false, colour)
  i = i + dotGet(64, dot6R, dot6G, dot6B, bgR, bgG, bgB, fgR, fgG, fgB, false, false, colour)
  i = i + dotGet(128, dot7R, dot7G, dot7B, bgR, bgG, bgB, fgR, fgG, fgB, true, true, colour)
  str = str .. unicode.char(i)
  ca = ca + 1
 end
 if str ~= "" then
  span(x, y, str, bg, fg)
 end
end

heldRef = {
 calcLine = calcLine,
 new = function (x, y, w, h, cbs, colour)
  local control
  control = {
   x = x,
   y = y,
   w = w,
   h = h,
   selectable = cbs.selectable,
   key = cbs.key,
   clipboard = cbs.clipboard,
   touch = cbs.touch and cTransform(cbs.touch),
   drag = cbs.drag and cTransform(cbs.drag),
   drop = cbs.drop and cTransform(cbs.drop),
   scroll = cbs.scroll and cTransform(cbs.scroll),
   line = function (window, x, y, iy, bg, fg, selected)
    local colour = colour
    local depth = window.getDepth()
    if depth <= 1 then
     colour = nil
    end
    calcLine(x, y, control.w, window.span, function (xb, yb)
     return cbs.get(window, xb + 1, yb + (iy * 4) - 3, bg, fg, selected, colour)
    end, colour)
   end,
  }
  return control
 end,
}
return heldRef