module BBS::BlockFont

A block font five pixels high for a board’s logo: the letters A-Z, the digits and some signs, most three pixels wide, a pixel of space between them. A modern terminal shows it in half blocks, two pixel rows to a line (::half_blocks); a Commodore 64 in reversed spaces, a pixel row to a line (::petscii). A word of nine letters is 35 columns wide, so it fits the C64’s 40.

A glyph is five Strings, # for a set pixel and . for a clear one. Every method takes glyphs, a Hash of glyphs over FONT, for another shape of a letter (NARROW_I, WIDE_W) or one of the board’s own.

BBS::BlockFont.half_blocks('WARP')
BBS::BlockFont.petscii('SCRIPTORIUM', colors: [WH, WH, YE, YE, CY],
                       glyphs: BBS::BlockFont::NARROW_I)

Constants

CLEAR: A clear pixel in a glyph row.
FONT: The glyphs: a character => its five rows.
HALF: A pair of pixels, the upper and the lower, => its half block.
HEIGHT: The pixel rows of a glyph.
NARROW_I: An I one pixel wide, a plain stroke.
SET: A set pixel in a glyph row.
WIDE_W: A W five pixels wide, with the middle stroke.

Public Class Methods

glyph (char, glyphs: {})

Source

# File lib/bbs/block_font.rb, line 56
def self.glyph(char, glyphs: {})
  glyphs[char] || FONT[char] || glyphs[char.upcase] || FONT.fetch(char.upcase)
end

The five rows of char (looked up as it is, then in capitals) in glyphs over FONT. Raises KeyError for a character the font lacks.

half_blocks (word, glyphs: {}, colors: nil, reset: Ansi::RESET)

Source

# File lib/bbs/block_font.rb, line 83
def self.half_blocks(word, glyphs: {}, colors: nil, reset: Ansi::RESET)
  lines = pixel_pairs(rows(word, glyphs: glyphs)).map { |pairs| pairs.map { |pair| HALF[pair] }.join }
  return lines if colors.nil?

  lines.each_with_index.map { |line, i| "#{color_of(colors, i)}#{line}#{reset}" }
end

word in three rows of half blocks (█ ▀ ▄ and space), the five pixel rows two by two, the last with a clear row under it. Each row is as wide as the word.

colors: an Array of SGR sequences, one a row, or one sequence for all: each row starts with its colour and ends with reset; nil for bare rows
reset: what ends a coloured row

Returns the rows, an Array of three Strings.

petscii (word, colors:, glyphs: {}, indent: 0, reset: Ansi::GREY, reverse: Ansi::REVERSE, normal: Ansi::REVERSE_OFF)

Source

# File lib/bbs/block_font.rb, line 119
def self.petscii(word, colors:, glyphs: {}, indent: 0, reset: Ansi::GREY, reverse: Ansi::REVERSE, normal: Ansi::REVERSE_OFF)
  rows(word, glyphs: glyphs).each_with_index.map do |row, i|
    "#{' ' * indent}#{color_of(colors, i)}#{reversed(row, reverse: reverse, normal: normal)}#{reset}"
  end
end

word in five rows of reversed spaces (::reversed) for a C64, each row indent spaces in, then its colour, then the pixels, then reset.

colors: an Array of SGR sequences (BBS::Petscii::Colors), one a row, or one sequence for all
indent: the spaces before each row
reset: what ends each row

Returns the rows, an Array of five Strings.

BBS::BlockFont.petscii('WARP', colors: [LB, LB, CY, CY, WH], indent: 10)

reversed (row, reverse: Ansi::REVERSE, normal: Ansi::REVERSE_OFF)

Source

# File lib/bbs/block_font.rb, line 104
def self.reversed(row, reverse: Ansi::REVERSE, normal: Ansi::REVERSE_OFF)
  row.gsub(/#{SET}+/o) { |run| "#{reverse}#{' ' * run.size}#{normal}" }.tr(CLEAR, ' ')
end

One pixel row, a String of # and . (or spaces), as reversed spaces: every run of set pixels between reverse and normal, the clear ones plain spaces.

BBS::BlockFont.reversed('#.##')   # => "\e[7m \e[27m \e[7m  \e[27m"

rows (word, glyphs: {})

Source

# File lib/bbs/block_font.rb, line 65
def self.rows(word, glyphs: {})
  chars = word.to_s.chars
  Array.new(HEIGHT) { |row| chars.map { |c| glyph(c, glyphs: glyphs)[row] }.join(CLEAR) }
end

The five pixel rows of word, its glyphs side by side with a clear column between them: an Array of Strings of # and .. Raises KeyError for a character the font lacks.

BBS::BlockFont.rows('HI').first   # => "#.#.###"

width (word, glyphs: {})

Source

# File lib/bbs/block_font.rb, line 71
def self.width(word, glyphs: {}) = rows(word, glyphs: glyphs).first.length

The columns word takes.