php如何生成code128条形码

self::STARTA,'B'=>self::STARTB,'C'=>self::STARTC);
  private $code ='';
  private $bin_code ='';
  private $text ='';
  public function __construct($code='',$text='',$type='B')
  {
    if (in_array($type,array('A','B','C')))
      $this->setType($type);
    else
      $this->setType('B');
    if ($code !=='')
      $this->setCode($code);
    if ($text !=='')
      $this->setText($text);
  }
  public function setUnitWidth($unit_width)
  {
    $this->unit_width = $unit_width;
    $this->quiet_zone = $this->unit_width*6;
    $this->font_height = $this->unit_width*15;
    if (!$this->is_set_height)
    {
      $this->heith = $this->unit_width*35;
    }
  }
  public function setFontType($font_type)
  {
    $this->font_type = $font_type;
  }
  public function setBgcolor($bgcoloe)
  {
    $this->bgcolor = $bgcoloe;
  }
  public function setColor($color)
  {
    $this->color = $color;
  }
  public function setCode($code)
  {
    if ($code !='')
    {
      $this->code= $code;
      if ($this->text ==='')
        $this->text = $code;
    }
  }
  public function setText($text)
  {
    $this->text = $text;
  }
  public function setType($type)
  {
    $this->type = $type;
  }
  public function setHeight($height)
  {
    $this->height = $height;
    $this->is_set_height = true;
  }
  private function getValueFromChar($ch)
  {
    $val = ord($ch);
    try
    {
      if ($this->type =='A')
      {
        if ($val > 95)
          throw new Exception(' illegal barcode character '.$ch.' for code128A in '.__FILE__.' on line '.__LINE__);
        if ($val type =='B')
      {
        if ($val  127)
          throw new Exception(' illegal barcode character '.$ch.' for code128B in '.__FILE__.' on line '.__LINE__);
        else
          $val -=32;
      }
      else
      {
        if (!is_numeric($ch) || (int)$ch  99)
          throw new Exception(' illegal barcode character '.$ch.' for code128C in '.__FILE__.' on line '.__LINE__);
        else
        {
          if (strlen($ch) ==1)
            $ch .='0';
          $val = (int)($ch);
        }
      }
    }
    catch(Exception $ex)
    {
      errorlog('die',$ex->getMessage());
    }
    return $val;
  }
  private function parseCode()
  {
    $this->type=='C'?$step=2:$step=1;
    $val_sum = $this->start_codes[$this->type];
    $this->width = 35;
    $this->bin_code = $this->codes[$val_sum];
    for($i =0;$icode);$i+=$step)
    {
      $this->width +=11;
      $ch = substr($this->code,$i,$step);
      $val = $this->getValueFromChar($ch);
      $val_sum += $val;
      $this->bin_code .= $this->codes[$val];
    }
    $this->width *=$this->unit_width;
    $val_sum = $val_sum%103;
    $this->valid_code = $val_sum;
    $this->bin_code .= $this->codes[$this->valid_code];
    $this->bin_code .= $this->codes[self::STOP];
  }
  public function getValidCode()
  {
    if ($this->valid_code == -1)
      $this->parseCode();
    return $this->valid_code;
  }
  public function getWidth()
  {
    if ($this->width ==-1)
      $this->parseCode();
    return $this->width;
  }
  public function getHeight()
  {
    if ($this->width ==-1)
      $this->parseCode();
    return $this->height;
  }
  public function createBarCode($image_type ='png',$file_name=null)
  {
    $this->parseCode();
    $this->image = ImageCreate($this->width+2*$this->quiet_zone,$this->heith + $this->font_height);
    $this->bgcolor = imagecolorallocate($this->image,$this->bgcolor >> 16,($this->bgcolor >> 8)&0x00FF,$this->bgcolor & 0xFF);
    $this->color = imagecolorallocate($this->image,$this->color >> 16,($this->color >> 8)&0x00FF,$this->color & 0xFF);
    ImageFilledRectangle($this->image, 0, 0, $this->width + 2*$this->quiet_zone,$this->heith + $this->font_height, $this->bgcolor);
    $sx = $this->quiet_zone;
    $sy = $this->font_height -1;
    $fw = 10; //編號為2或3的字體的寬度為10，為4或5的字體寬度為11
    if ($this->font_type >3)
    {
      $sy++;
      $fw=11;
    }
    $ex = 0;
    $ey = $this->heith + $this->font_height - 2;
    for($i=0;$ibin_code);$i++)
    {
      $ex = $sx + $this->unit_width*(int) $this->bin_code{$i} -1;
      if ($i%2==0)
        ImageFilledRectangle($this->image, $sx, $sy, $ex,$ey, $this->color);
      $sx =$ex + 1;
    }
    $t_num = strlen($this->text);
    $t_x = $this->width/$t_num;
    $t_sx = ($t_x -$fw)/2;    //目的为了使文字居中平均分布
    for($i=0;$iimage,$this->font_type,6*$this->unit_width +$t_sx +$i*$t_x,0,$this->text{$i},$this->color);
    }
    if (!$file_name)
    {
      header("Content-Type: image/".$image_type);
    }
    switch ($image_type)
    {
      case 'jpg':
      case 'jpeg':
        Imagejpeg($this->image,$file_name);
        break;
      case 'png':
        Imagepng($this->image,$file_name);
        break;
      case 'gif':
        break;
        Imagegif($this->image,$file_name);
      default:
        Imagepng($this->image,$file_name);
        break;
    }
  }
}
$barcode = new BarCode128('88888888');
$barcode->createBarCode();
?>