Class AnimatedWaveDemo < Object

# File ext/tk/sample/demos-en/aniwave.rb, line 51
def initialize(frame, dir=:left)
  @direction = dir

  # create canvas widget
  @c = TkCanvas.new(frame, :width=>300, :height=>200,
                    :background=>'black')
  @c.pack(:padx=>10, :pady=>10, :expand=>true)

  # Creates a coordinates list of a wave.
  @waveCoords = []
  @backupCoords = []
  n = 0
  (-10..300).step(5){|n| @waveCoords << [n, 100]; @backupCoords << [n, 100] }
  n = 305
  @waveCoords << [n, 0]; @backupCoords << [n, 0]
  @waveCoords << [n+5, 200]; @backupCoords << [n+5, 200]
  @coordsLen = @waveCoords.length

  # Create a smoothed line and arrange for its coordinates to be the
  # contents of the variable waveCoords.
  @line = TkcLine.new(@c, @waveCoords,
                      :width=>1, :fill=>'green', :smooth=>true)

  # Main animation "loop".
  # Theoretically 100 frames-per-second (==10ms between frames)
  @timer = TkTimer.new(10){ basicMotion; reverser }

  # Arrange for the animation loop to stop when the canvas is deleted
  @c.bindtags_unshift(TkBindTag.new('Destroy'){ @timer.stop })
end

# File ext/tk/sample/demos-en/aniwave.rb, line 85
def basicMotion
  @backupCoords, @waveCoords = @waveCoords, @backupCoords
  (0...@coordsLen).each{|idx|
    if @direction == :left
      @waveCoords[idx][1] = @backupCoords[(idx+1 == @coordsLen)? 0: idx+1][1]
    else
      @waveCoords[idx][1] = @backupCoords[(idx == 0)? -1: idx-1][1]
    end
  }
  @line.coords(@waveCoords)
end

# File ext/tk/sample/demos-en/aniwave.rb, line 109
def move
  @timer.start
end

# File ext/tk/sample/demos-en/aniwave.rb, line 100
def reverser
  if @waveCoords[0][1] < 10
    @direction = :right
  elsif @waveCoords[-1][1] < 10
    @direction = :left
  end
end

# File ext/tk/sample/demos-en/aniwave.rb, line 113
def stop
  @timer.stop
end