SoundGraph.rb

SoundGraph.rb

include Java

import javax.swing.SwingUtilities
import javax.swing.JFrame
import javax.swing.JPanel
import javax.swing.BorderFactory
import java.awt.Color
import java.awt.Dimension
import java.awt.Graphics

class SoundGraph
  include java.lang.Runnable

  SAMPLING_RATE = 44000
  PI2 = Math::PI * 2
  AMPLITUDE = 500

  def createAndShowGUI
    # samples = makeSinWave
    samples = makeSquareWave
    f = JFrame.new("Swing Paint Demo")
    f.setDefaultCloseOperation(JFrame::EXIT_ON_CLOSE)
    f.add(SoundGraphPanel.new(samples))
    f.pack
    f.setVisible(true)
  end

  def run
    createAndShowGUI
  end

  def makeSinWave
    fr = 440
    samples = []
    ph = 0.0
    SAMPLING_RATE.times do |i|
      samples[i] = (AMPLITUDE * Math::sin(ph)).to_i
      ph += PI2 * fr / SAMPLING_RATE
    end
    return samples
  end

  def makeSquareWave
    fr = 440.0
    samples = []
    len = SAMPLING_RATE / fr
    SAMPLING_RATE.times do |i|
      if i % len < len / 2
        samples[i] = AMPLITUDE
      else
        samples[i] = -AMPLITUDE
      end
    end
    return samples
  end
end

class SoundGraphPanel < JPanel
  def initialize(samples)
    super()
    @samples = samples
    setBorder(BorderFactory.createLineBorder(Color::black))
  end

  def getPreferredSize
    return Dimension.new(1024, 1024)
  end

  def paintComponent(g)
    super(g)
    @samples.each_with_index do |value, i|
      g.drawLine(i, value + 510, i, value + 510)
    end
  end
end

SwingUtilities.invokeLater(SoundGraph.new)