Aegisub/aegisub/automation/include/aegisub/util.lua

local sformat = string.format
local copy
copy = function(tbl)
  return (function()
    local _tbl_0 = { }
    for k, v in pairs(tbl) do
      _tbl_0[k] = v
    end
    return _tbl_0
  end)()
end
local deep_copy
deep_copy = function(tbl)
  local seen = { }
  copy = function(val)
    if type(tbl) ~= 'table' then
      return val
    end
    if seen[tbl] then
      return seen[val]
    end
    seen[val] = tbl
    return (function()
      local _tbl_0 = { }
      for k, v in pairs(val) do
        _tbl_0[k] = copy(v)
      end
      return _tbl_0
    end)()
  end
  return copy(tbl)
end
local ass_color
ass_color = function(r, g, b)
  return sformat("&H%02X%02X%02X&", b, g, r)
end
local ass_alpha
ass_alpha = function(a)
  return sformat("&H%02X&", a)
end
local ass_style_color
ass_style_color = function(r, g, b, a)
  return sformat("&H%02X%02X%02X%02X", a, b, g, r)
end
local extract_color
extract_color = function(s)
  local a, b, g, r
  a, b, g, r = s:match('&H(%x%x)(%x%x)(%x%x)(%x%x)')
  if a then
    return tonumber(r, 16), tonumber(g, 16), tonumber(b, 16), tonumber(a, 16)
  end
  b, g, r = s:match('&H(%x%x)(%x%x)(%x%x)&')
  if b then
    return tonumber(r, 16), tonumber(g, 16), tonumber(b, 16), 0
  end
  a = s:match('&H(%x%x)&')
  if a then
    return 0, 0, 0, tonumber(a, 16)
  end
  r, g, b, a = s:match('#(%x%x)(%x?%x?)(%x?%x?)(%x?%x?)')
  if r then
    return tonumber(r, 16), tonumber(g, 16) or 0, tonumber(b, 16) or 0, tonumber(a, 16) or 0
  end
end
local alpha_from_style
alpha_from_style = function(scolor)
  return ass_alpha(select(4, extract_color(scolor)))
end
local color_from_style
color_from_style = function(scolor)
  local r, g, b = extract_color(scolor)
  return ass_color(r or 0, g or 0, b or 0)
end
local HSV_to_RGB
HSV_to_RGB = function(H, S, V)
  local r, g, b = 0, 0, 0
  if S == 0 then
    r = self:clamp(V * 255, 0, 255)
    g = r
    b = r
  else
    H = math.abs(H) % 360
    local Hi = math.floor(H / 60)
    local f = H / 60.0 - Hi
    local p = V * (1 - S)
    local q = V * (1 - f * S)
    local t = V * (1 - (1 - f) * S)
    if Hi == 0 then
      r = V * 255.0
      g = t * 255.0
      b = p * 255.0
    elseif Hi == 1 then
      r = q * 255.0
      g = V * 255.0
      b = p * 255.0
    elseif Hi == 2 then
      r = p * 255.0
      g = V * 255.0
      b = t * 255.0
    elseif Hi == 3 then
      r = p * 255.0
      g = q * 255.0
      b = V * 255.0
    elseif Hi == 4 then
      r = t * 255.0
      g = p * 255.0
      b = V * 255.0
    elseif Hi == 5 then
      r = V * 255.0
      g = p * 255.0
      b = q * 255.0
    else
      error("math.floor(H % 360 / 60) should be [0, 6), is " .. tostring(Hi) .. "?")
    end
  end
  return r, g, b
end
local HSL_to_RGB
HSL_to_RGB = function(H, S, L)
  local r, g, b
  H = math.abs(H) % 360
  S = clamp(S, 0, 1)
  L = clamp(L, 0, 1)
  if S == 0 then
    r = L
    g = L
    b = L
  else
    local Q
    if L < 0.5 then
      Q = L * (1.0 + S)
    else
      Q = L + S - (L * S)
    end
    local P = 2.0 * L - Q
    local Hk = H / 360
    local Tr, Tg, Tb
    if Hk < 1 / 3 then
      Tr = Hk + 1 / 3
      Tg = Hk
      Tb = Hk + 2 / 3
    elseif Hk > 2 / 3 then
      Tr = Hk - 2 / 3
      Tg = Hk
      Tb = Hk - 1 / 3
    else
      Tr = Hk + 1 / 3
      Tg = Hk
      Tb = Hk - 1 / 3
    end
    local get_component
    get_component = function(T)
      if T < 1 / 6 then
        return P + ((Q - P) * 6.0 * T)
      elseif 1 / 6 <= T and T < 1 / 2 then
        return Q
      elseif 1 / 2 <= T and T < 2 / 3 then
        return P + ((Q - P) * (2 / 3 - T) * 6.0)
      else
        return P
      end
    end
    r = get_component(Tr)
    g = get_component(Tg)
    b = get_component(Tb)
  end
  return math.floor(r * 255 + 0.5), math.floor(g * 255 + 0.5), math.floor(b * 255 + 0.5)
end
local trim
trim = function(s)
  return s:gsub('^%s*(.-)%s*$', '%1')
end
local headtail
headtail = function(s)
  local a, b, head, tail = s:find('(.-)%s+(.*)')
  if a then
    return head, tail
  else
    return s, ''
  end
end
local words
words = function(s)
  return function()
    if s == '' then
      return 
    end
    local head, tail = headtail(s)
    s = tail
    return head
  end
end
local clamp
clamp = function(val, min, max)
  if val < min then
    return min
  elseif val > max then
    return max
  else
    return val
  end
end
local interpolate
interpolate = function(pct, min, max)
  if pct <= 0 then
    return min
  elseif pct >= 1 then
    return max
  else
    return pct * (max - min) + min
  end
end
local interpolate_color
interpolate_color = function(pct, first, last)
  local r1, g1, b1 = extract_color(first)
  local r2, g2, b2 = extract_color(last)
  local r, g, b = interpolate(pct, r1, r2), interpolate(pct, g1, g2), interpolate(pct, b1, b2)
  return ass_color(r, g, b)
end
local interpolate_alpha
interpolate_alpha = function(pct, first, last)
  return ass_alpha(interpolate(pct, select(4, extract_color(first)), select(4, extract_color(last))))
end
return {
  copy = copy,
  deep_copy = deep_copy,
  ass_color = ass_color,
  ass_alpha = ass_alpha,
  ass_style_color = ass_style_color,
  extract_color = extract_color,
  alpha_from_style = alpha_from_style,
  color_from_style = color_from_style,
  HSV_to_RGB = HSV_to_RGB,
  HSL_to_RGB = HSL_to_RGB,
  trim = trim,
  headtail = headtail,
  words = words,
  clamp = clamp,
  interpolate = interpolate,
  interpolate_color = interpolate_color,
  interpolate_alpha = interpolate_alpha
}