class Verse::Truncation

A class responsible for text truncation operations

Constants

DEFAULT_LENGTH
DEFAULT_TRAILING

Attributes

separator[R]
text[R]
trailing[R]

Public Class Methods

new(text, options = {}) click to toggle source

Initialize a Truncation

@param [String] text

the text to be truncated

@param [Hash] options

@option options [Symbol] :separator the character for splitting words
@option options [Symbol] :trailing  the character for ending sentence

@api public

# File lib/verse/truncation.rb, line 24
def initialize(text, options = {})
  @text      = text.dup.freeze
  @separator = options.fetch(:separator) { nil }
  @trailing  = options.fetch(:trailing) { DEFAULT_TRAILING }
end
truncate(text, truncate_at, options = {}) click to toggle source

Truncate a text at a given length

@see Verse::Truncation#truncate

@api public

# File lib/verse/truncation.rb, line 35
def self.truncate(text, truncate_at, options = {})
  new(text, options).truncate(truncate_at, options)
end

Public Instance Methods

truncate(truncate_at = DEFAULT_LENGTH, options = {}) click to toggle source

Truncate a text at a given length (defualts to 30)

@example

truncation = Verse::Truncation.new
  "The sovereignest thing on earth is parmacetti for an inward bruise."

truncation.truncate
# => "The sovereignest thing on ear…"

truncate(20)
# => "The sovereignest th…"

truncate(20, separator: ' ' )
# => "The sovereignest…"

truncate(40, trailing: '... (see more)' )
# => "The sovereignest thing on... (see more)"

@api public

# File lib/verse/truncation.rb, line 58
def truncate(truncate_at = DEFAULT_LENGTH, options = {})
  if display_width(text) <= truncate_at.to_i || truncate_at.to_i.zero?
    return text.dup
  end
  trail      = options.fetch(:trailing) { trailing }
  separation = options.fetch(:separator) { separator }
  width      = display_width(text)
  sanitized_text = Sanitizer.sanitize(text)

  return text if width <= truncate_at

  length_without_trailing = truncate_at - display_width(trail)
  chars = to_chars(sanitized_text).to_a
  stop  = chars[0, length_without_trailing].rindex(separation)
  slice_length = stop || length_without_trailing
  sliced_chars = chars[0, slice_length]
  original_chars = to_chars(text).to_a[0, 3 * slice_length]
  shorten(original_chars, sliced_chars, length_without_trailing).join + trail
end

Protected Instance Methods

display_width(string) click to toggle source

@api private

# File lib/verse/truncation.rb, line 113
def display_width(string)
  Unicode::DisplayWidth.of(Sanitizer.sanitize(string))
end
shorten(original_chars, chars, length_without_trailing) click to toggle source

Perform actual shortening of the text

@return [String]

@api private

# File lib/verse/truncation.rb, line 87
def shorten(original_chars, chars, length_without_trailing)
  truncated = []
  char_width = display_width(chars[0])
  while length_without_trailing - char_width > 0
    orig_char = original_chars.shift
    char = chars.shift
    break unless char
    while orig_char != char # consume ansi
      ansi = true
      truncated << orig_char
      orig_char = original_chars.shift
    end
    truncated << char
    char_width = display_width(char)
    length_without_trailing -= char_width
  end
  truncated << ["\e[0m"] if ansi
  truncated
end
to_chars(text) click to toggle source

@api private

# File lib/verse/truncation.rb, line 108
def to_chars(text)
  UnicodeUtils.each_grapheme(text)
end