class BBS::Petscii::Screen

The screen of one call on a line-by-line board, and the ways such a board talks: a reversed title bar, pages of text that wait for RETURN, numbered cursor lists (BBS::Selector), single-key and cursor menus, a line field (BBS::Field) and the full-screen editor (BBS::Editor).

It is made for a Commodore 64, a 40×25 screen on a session switched with session.petscii!, which makes PETSCII of what the screen writes. Given cols and rows it serves a modern terminal too: on a session that is not PETSCII, cls homes the cursor and the text is not made plain.

The colours are the ANSI constants of BBS::Petscii::Colors, included, so a subclass writes WH, LG … bare. A board subclasses it for methods of its own:

class Screen < BBS::Petscii::Screen
  def banner(text) = puts(" #{YE}#{text}#{LG}")
end

screen = Screen.new(runner.session)
screen.title('the shelves', 'q: back')
book = screen.pick('the shelves', books, &:title)

Constants

CHROME: The rows above and below a page of text: the title bar, the line before the key prompt, the prompt and the screen’s last row.
COLS: The width of the C64 screen.
EMPTY: What page and pick show for nothing.
MODERN_CLEAR: The clear screen of a modern terminal: colours reset, cursor home.
PAGE: The lines of text on a C64 page (page_size of a 40×25 screen).
PICK_HINT: The status row of pick.
ROWS: The height of the C64 screen.
WIDTH: The width of a wrapped paragraph on the C64: a column of margin on both sides.

Attributes

cols [R]

The screen’s width and height in characters.

rows [R]

The screen’s width and height in characters.

session [R]

The session written to and read from (BBS::Session or one that quacks like it).

width [R]

The width a paragraph wraps to: cols less two.

Public Class Methods

new (session, cols: COLS, rows: ROWS)

Source

# File lib/bbs/petscii/screen.rb, line 61
def initialize(session, cols: COLS, rows: ROWS)
  @session = session
  @cols    = cols
  @rows    = rows
  @width   = cols - 2
end

Creates the screen of session, cols × rows (default the C64’s 40×25).

Public Instance Methods

bell ()

Source

# File lib/bbs/petscii/screen.rb, line 88
def bell = write("\a")

Rings the bell.

cls ()

Source

# File lib/bbs/petscii/screen.rb, line 85
def cls = write(petscii? ? Petscii::CLEAR : MODERN_CLEAR)

Clears the screen: the C64’s CLR, or MODERN_CLEAR on a modern terminal.

fit (lines, width = @cols - 1)

Source

# File lib/bbs/petscii/screen.rb, line 118
def fit(lines, width = @cols - 1)
  lines.flat_map do |l|
    next [''] if l.to_s.empty?

    indent = FrameBuffer.plain(l)[/\A */]
    first, *rest = wrap(l, width)
    next [first] if rest.empty?

    [first, *wrap(rest.join(' '), width - indent.size).map { |r| "#{indent}#{r}" }]
  end
end

Every line of lines cut to width, the long ones wrapped under their own indent. An empty line stays one. Returns the lines.

key (timeout: nil)

Source

# File lib/bbs/petscii/screen.rb, line 140
def key(timeout: nil)
  k = @session.readkey(timeout: timeout)
  raise IOError, 'the caller hung up' if k.nil?

  k
end

Reads a key (see BBS::Telnet#readkey): :idle after timeout seconds, when given. Raises IOError when the caller hangs up.

page (heading, lines, right: '', wait: true, room: 1, numbers: false)

Source

# File lib/bbs/petscii/screen.rb, line 159
def page(heading, lines, right: '', wait: true, room: 1, numbers: false)
  lines  = fit(lines)
  lines  = [" #{GR}#{EMPTY}#{LG}"] if lines.empty?
  chunks = lines.each_slice(wait ? page_size : page_size - room).to_a
  chunks.each_with_index do |chunk, i|
    title(heading, numbers ? "#{right}#{i + 1}/#{chunks.size}" : right)
    chunk.each { |l| puts l }
    break unless turn_page?(i == chunks.size - 1, wait)
  end
  nil
end

Shows lines (fit to the screen) one page_size at a time, each page under the title of heading and right, waiting for RETURN after each; q, ← or RUN/STOP leave early.

right: the right end of the title bar
wait: false: the last page does not wait, and leaves room rows free for what follows (a command line)
room: the rows the last page leaves free with wait false
numbers: true: the title bar shows the page, 2/5, after right

Returns nil.

page_size ()

Source

# File lib/bbs/petscii/screen.rb, line 69
def page_size = @rows - CHROME

The lines of text on a page under the title bar: rows less CHROME.

petscii? ()

Source

# File lib/bbs/petscii/screen.rb, line 73
def petscii? = !@session.respond_to?(:petscii?) || @session.petscii?

Whether the session speaks PETSCII; true for a session that cannot tell.

plain (text)

Source

# File lib/bbs/petscii/screen.rb, line 114
def plain(text) = petscii? ? Petscii.plain(text) : text.to_s

text in characters the C64 shows one to a cell (BBS::Petscii.plain) on a PETSCII session; as it is on a modern one.

puts (text = '')

Source

# File lib/bbs/petscii/screen.rb, line 79
def puts(text = '')
  write("#{text}\r\n")
end

Writes text and a line end.

rule (color: DG)

Source

# File lib/bbs/petscii/screen.rb, line 106
def rule(color: DG) = puts("#{color}#{'─' * (@cols - 1)}#{LG}")

Writes a horizontal line in color, the screen’s width less one.

say (text, color: LG)

Source

# File lib/bbs/petscii/screen.rb, line 134
def say(text, color: LG)
  wrap(plain(text)).each { |l| puts " #{color}#{l}#{LG}" }
end

Writes text (made plain) as a paragraph in color, wrapped to width and indented by a space.

screen.say('Posted.', color: GN)

title (text, right = '')

Source

# File lib/bbs/petscii/screen.rb, line 91
def title(text, right = '')
  cls
  puts title_bar(text, right)
end

Clears the screen and writes the title_bar of text and right.

title_bar (text, right = '')

Source

# File lib/bbs/petscii/screen.rb, line 99
def title_bar(text, right = '')
  room = @cols - right.length - 1
  bar  = " #{plain(text)}".ljust(room)[0, room] + "#{right} "
  "#{CY}#{RV}#{bar}#{RO}#{LG}"
end

A reversed cyan bar the width of the screen less its last column: text (made plain) at the left, right at the right; text is cut where it would run into right.

wrap (text, width = @width)

Source

# File lib/bbs/petscii/screen.rb, line 110
def wrap(text, width = @width) = FrameBuffer.wrap_ansi(text.to_s, width)

text word-wrapped to width columns, ANSI colours kept: an Array of lines (BBS::FrameBuffer.wrap_ansi).

write (text)

Source

# File lib/bbs/petscii/screen.rb, line 76
def write(text) = @session.write(text)

Writes text to the session as it is.