Module: Thaum::Rendering::BoxDrawing

Defined in:

lib/thaum/rendering/box_drawing.rb

Constant Summary

SEGMENTS =

char => [up, down, left, right] weights (0=none, 1=light, 2=heavy, 3=double)

{
  # ----- Pure light --------------------------------------------------
  "─" => [0, 0, 1, 1],
  "│" => [1, 1, 0, 0],
  "┌" => [0, 1, 0, 1],
  "┐" => [0, 1, 1, 0],
  "└" => [1, 0, 0, 1],
  "┘" => [1, 0, 1, 0],
  "├" => [1, 1, 0, 1],
  "┤" => [1, 1, 1, 0],
  "┬" => [0, 1, 1, 1],
  "┴" => [1, 0, 1, 1],
  "┼" => [1, 1, 1, 1],
  "╴" => [0, 0, 1, 0],
  "╵" => [1, 0, 0, 0],
  "╶" => [0, 0, 0, 1],
  "╷" => [0, 1, 0, 0],
  # Rounded corners share signatures with the non-rounded corners.
  "╭" => [0, 1, 0, 1],
  "╮" => [0, 1, 1, 0],
  "╰" => [1, 0, 0, 1],
  "╯" => [1, 0, 1, 0],

  # ----- Pure heavy --------------------------------------------------
  "━" => [0, 0, 2, 2],
  "┃" => [2, 2, 0, 0],
  "┏" => [0, 2, 0, 2],
  "┓" => [0, 2, 2, 0],
  "┗" => [2, 0, 0, 2],
  "┛" => [2, 0, 2, 0],
  "┣" => [2, 2, 0, 2],
  "┫" => [2, 2, 2, 0],
  "┳" => [0, 2, 2, 2],
  "┻" => [2, 0, 2, 2],
  "╋" => [2, 2, 2, 2],
  "╸" => [0, 0, 2, 0],
  "╹" => [2, 0, 0, 0],
  "╺" => [0, 0, 0, 2],
  "╻" => [0, 2, 0, 0],

  # ----- Mixed light/heavy corners (U+250D-U+251B minus pures) -------
  "┍" => [0, 1, 0, 2], # d light, r heavy
  "┎" => [0, 2, 0, 1], # d heavy, r light
  "┑" => [0, 1, 2, 0], # d light, l heavy
  "┒" => [0, 2, 1, 0], # d heavy, l light
  "┕" => [1, 0, 0, 2], # u light, r heavy
  "┖" => [2, 0, 0, 1], # u heavy, r light
  "┙" => [1, 0, 2, 0], # u light, l heavy
  "┚" => [2, 0, 1, 0], # u heavy, l light

  # ----- Mixed light/heavy left-tees (U+251D-U+2522) -----------------
  "┝" => [1, 1, 0, 2],
  "┞" => [2, 1, 0, 1],
  "┟" => [1, 2, 0, 1],
  "┠" => [2, 2, 0, 1],
  "┡" => [2, 1, 0, 2],
  "┢" => [1, 2, 0, 2],

  # ----- Mixed light/heavy right-tees (U+2525-U+252A) ----------------
  "┥" => [1, 1, 2, 0],
  "┦" => [2, 1, 1, 0],
  "┧" => [1, 2, 1, 0],
  "┨" => [2, 2, 1, 0],
  "┩" => [2, 1, 2, 0],
  "┪" => [1, 2, 2, 0],

  # ----- Mixed light/heavy top-tees (U+252D-U+2532) ------------------
  "┭" => [0, 1, 2, 1],
  "┮" => [0, 1, 1, 2],
  "┯" => [0, 1, 2, 2],
  "┰" => [0, 2, 1, 1],
  "┱" => [0, 2, 2, 1],
  "┲" => [0, 2, 1, 2],

  # ----- Mixed light/heavy bottom-tees (U+2535-U+253A) ---------------
  "┵" => [1, 0, 2, 1],
  "┶" => [1, 0, 1, 2],
  "┷" => [1, 0, 2, 2],
  "┸" => [2, 0, 1, 1],
  "┹" => [2, 0, 2, 1],
  "┺" => [2, 0, 1, 2],

  # ----- Mixed light/heavy crosses (U+253D-U+254A) -------------------
  "┽" => [1, 1, 2, 1],
  "┾" => [1, 1, 1, 2],
  "┿" => [1, 1, 2, 2],
  "╀" => [2, 1, 1, 1],
  "╁" => [1, 2, 1, 1],
  "╂" => [2, 2, 1, 1],
  "╃" => [2, 1, 2, 1],
  "╄" => [2, 1, 1, 2],
  "╅" => [1, 2, 2, 1],
  "╆" => [1, 2, 1, 2],
  "╇" => [2, 1, 2, 2],
  "╈" => [1, 2, 2, 2],
  "╉" => [2, 2, 2, 1],
  "╊" => [2, 2, 1, 2],

  # ----- Pure double -------------------------------------------------
  "═" => [0, 0, 3, 3],
  "║" => [3, 3, 0, 0],
  "╔" => [0, 3, 0, 3],
  "╗" => [0, 3, 3, 0],
  "╚" => [3, 0, 0, 3],
  "╝" => [3, 0, 3, 0],
  "╠" => [3, 3, 0, 3],
  "╣" => [3, 3, 3, 0],
  "╦" => [0, 3, 3, 3],
  "╩" => [3, 0, 3, 3],
  "╬" => [3, 3, 3, 3],

  # ----- Mixed light/double corners (U+2552-U+2559, U+255B-U+255C) ---
  "╒" => [0, 1, 0, 3], # d light, r double
  "╓" => [0, 3, 0, 1], # d double, r light
  "╕" => [0, 1, 3, 0],
  "╖" => [0, 3, 1, 0],
  "╘" => [1, 0, 0, 3],
  "╙" => [3, 0, 0, 1],
  "╛" => [1, 0, 3, 0],
  "╜" => [3, 0, 1, 0],

  # ----- Mixed light/double tees -------------------------------------
  "╞" => [1, 1, 0, 3],
  "╟" => [3, 3, 0, 1],
  "╡" => [1, 1, 3, 0],
  "╢" => [3, 3, 1, 0],
  "╤" => [0, 1, 3, 3],
  "╥" => [0, 3, 1, 1],
  "╧" => [1, 0, 3, 3],
  "╨" => [3, 0, 1, 1],
  "╪" => [1, 1, 3, 3],
  "╫" => [3, 3, 1, 1]
}.freeze

GLYPH_FROM_SEGMENTS =

up, down, left, right

> canonical glyph (non-rounded; light-form

preferred where a signature is ambiguous, e.g. the rounded corners).

SEGMENTS.each_with_object({}) do |(glyph, sig), out|
  # Skip rounded corners — their signatures collide with the non-
  # rounded light corners, which should win as the canonical form.
  next if %w[╭ ╮ ╰ ╯].include?(glyph)

  out[sig] ||= glyph
end.freeze

Class Method Summary

• .merge(existing:, incoming:) ⇒ Object

  Merge two glyphs.

Class Method Details

.merge(existing:, incoming:) ⇒ Object

Merge two glyphs. Returns the union glyph if both are known box-drawing chars and the resulting signature has a Unicode glyph; otherwise the incoming char (new-write-wins).

# File 'lib/thaum/rendering/box_drawing.rb', line 176

def self.merge(existing:, incoming:)
  seg_a = SEGMENTS[existing]
  seg_b = SEGMENTS[incoming]
  return incoming unless seg_a && seg_b

  merged = [seg_a, seg_b].transpose.map(&:max)
  GLYPH_FROM_SEGMENTS[merged] || incoming
end