Class: Track

Inherits:
Object
  • Object
show all
Defined in:
lib/tabscroll/track.rb

Overview

A full guitar tab, as shown on the screen. Note that it depends on an already-existing window to exist.

Constant Summary collapse

COMMENT_CHAR =

Any line on the file that starts with this char is completely ignored when processed. Useful for making use of tabs we currently can’t parse.

'#'

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(screen) ⇒ Track

Creates a Track that will be shown on screen. See Screen.



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# File 'lib/tabscroll/track.rb', line 20

def initialize(screen)
  @offset = 0
  @timer  = Timer.new
  @timer.start
  @speed  = 0
  @screen = screen
  @percent_completed = 0

  @raw_track = []
  @raw_track[0] = ""
  @raw_track[1] = ""
  @raw_track[2] = ""
  @raw_track[3] = ""
  @raw_track[4] = ""
  @raw_track[5] = ""
  @raw_track[6] = ""
end

Instance Attribute Details

#percent_completed ⇒ Object (readonly)

Returns the value of attribute percent_completed.



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# File 'lib/tabscroll/track.rb', line 15

def percent_completed
  @percent_completed
end

#screen ⇒ Object (readonly)

Returns the value of attribute screen.



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# File 'lib/tabscroll/track.rb', line 15

def screen
  @screen
end

#speed ⇒ Object

Returns the value of attribute speed.



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# File 'lib/tabscroll/track.rb', line 16

def speed
  @speed
end

Instance Method Details

#auto_scroll(option) ⇒ Object

Turns on/off Track’s auto scroll functionality.

Note that it won’t work anyways if you don’t keep calling update method.



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# File 'lib/tabscroll/track.rb', line 180

def auto_scroll option
  if option == true
    @timer.start if not @timer.running?
  else
    @timer.stop
  end
end

#begin ⇒ Object

Goes to the beginning of the Track.



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# File 'lib/tabscroll/track.rb', line 165

def begin
  @offset = 0
  @speed  = 0
end

#end ⇒ Object

Goes to the end of the Track.



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# File 'lib/tabscroll/track.rb', line 171

def end
  @offset = (@raw_track[0].length - @screen.width + 1).abs
  @speed  = 0
end

#load(filename) ⇒ Object

Loads and parses filename‘s contents into Track.



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# File 'lib/tabscroll/track.rb', line 39

def load filename
  if not File.exist? filename
    raise "Error: File '#{filename}' doesn't exist!"
  end
  if not File.file? filename
    raise "Error: '#{filename}' is not a file!"
  end

  file = File.new filename

  # The thing here is there's no way I can know in
  # advance how many lines the tab track will have.
  #
  # People put lots of strange things on them like
  # timing, comments, etecetera.
  #
  # So I will read all non-blank lines, creating a
  # counter. Then I will use it to display the track
  # onscreen.
  #
  # I will also make every line have the same width
  # as of the biggest one.

  # Any tab line MUST have EITHER:
  # ---1---9--|
  # or
  # |---3----0
  tab_line = /[-[:alnum:]*]\||\|[-[:alnum:]*]/

  # Duration of each note only has those chars.
  # So we look for anything BUT these chars.
  not_duration_line = /[^WHQESTX \.]/

  count = 0
  max_width = 0

  file.readlines.each do |line|
    next if line[0] == COMMENT_CHAR

    line.chomp!
    if line.empty?

      # Making sure everything will have the same width
      @raw_track.each_with_index do |t, i|
        if t.length < max_width
          @raw_track[i] += (' ' * (max_width - t.length))
        end
      end

      count = 0
      max_width = 0

    # Lines must be EITHER a tab_line OR a duration_line.
    # not not duration line means that
    # (I should find a better way of expressing myself on regexes)
    elsif (line =~ tab_line) or (not line =~ not_duration_line)
      @raw_track[count] += line

      if @raw_track[count].length > max_width
        max_width = @raw_track[count].length
      end

      count += 1

    end # Ignoring any other kind of line

    if count > 7
      raise "Error: Invalid format on '#{filename}'"
    end

  end
end

#scroll(n) ⇒ Object

Scrolls the guitar tab by n.

  • If n is positive, scroll forward.

  • If n is negative, scroll backward.



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# File 'lib/tabscroll/track.rb', line 154

def scroll n
  @offset += n

  left_limit  = 0
  right_limit = (@raw_track[0].length - @screen.width + 1).abs

  if @offset < left_limit  then @offset = left_limit  end
  if @offset > right_limit then @offset = right_limit end
end

#show ⇒ Object

Prints the track on the screen, along with string indicators on the left.

It is shown at the vertical center of the provided Screen, spanning it’s whole width.



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# File 'lib/tabscroll/track.rb', line 117

def show
  x = 1
  y = (@screen.height/2) - (@raw_track.size/2)

  # This both prints EADGBE and clears the whole screen,
  # printing spaces where the track was.
  #
  # Also, if we have only 5 tracks, we leave the sixth
  # indicator out of the screen.
  if @raw_track.last =~ /^ *$/
    @screen.mvaddstr(0, y,     "E" + (' ' * (@screen.width - 1)))
    @screen.mvaddstr(0, y + 1, "B" + (' ' * (@screen.width - 1)))
    @screen.mvaddstr(0, y + 2, "G" + (' ' * (@screen.width - 1)))
    @screen.mvaddstr(0, y + 3, "D" + (' ' * (@screen.width - 1)))
    @screen.mvaddstr(0, y + 4, "A" + (' ' * (@screen.width - 1)))
    @screen.mvaddstr(0, y + 5, "E" + (' ' * (@screen.width - 1)))
  else
    @screen.mvaddstr(0, y,     ' ' * @screen.width)
    @screen.mvaddstr(0, y + 1, "E" + (' ' * (@screen.width - 1)))
    @screen.mvaddstr(0, y + 2, "B" + (' ' * (@screen.width - 1)))
    @screen.mvaddstr(0, y + 3, "G" + (' ' * (@screen.width - 1)))
    @screen.mvaddstr(0, y + 4, "D" + (' ' * (@screen.width - 1)))
    @screen.mvaddstr(0, y + 5, "A" + (' ' * (@screen.width - 1)))
    @screen.mvaddstr(0, y + 6, "E" + (' ' * (@screen.width - 1)))
  end

  (0...@raw_track.size).each do |i|
    str = @raw_track[i]
    str = str[@offset..(@offset + @screen.width - 2)]
    @screen.mvaddstr(x, y + i, str)
  end
end

#update ⇒ Object

Updates Track’s auto scroll functionality.



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# File 'lib/tabscroll/track.rb', line 189

def update
  return if not @timer.running?

  current_completed = @offset + @screen.width - 1
  @percent_completed = ((100.0 * current_completed)/@raw_track[0].length).ceil

  if @timer.running? and @speed != 0
    if @timer.delta > (1/(@speed*0.5)).abs
      if @speed > 0
        self.scroll 1
        self.show
      else
        self.scroll -1
        self.show
      end

      @timer.restart
    end
  end
end