# File rbSnack/tkSnack.rb, line 778
    def waveform_to_canvas( canvas, x, y, options=nil, &op_block); 
      options=SnOp::makeOps(options, &op_block)  
      options['height']=canvas.height unless options.has_key? 'height'
      cmd = ["#{canvas.to_eval} create waveform #{x} #{y} -sound #{@name}"]
      Snack::exeTkCmd(cmd, options)
    end