Updating the repo with the updated version from a long time ago.

README.md

@@ -9,7 +9,34 @@ This is a re-working of [php-barcode](http://www.ashberg.de/php-barcode/ "php-ba
 
 Folke did a lot of good work, but it is nigh unreadable, I think, and I wanted to fix that. Because of this, too, it is really hard to add newer barcode types.
 
+I also needed an on-the-fly barcode solution for a freelance job. This code has been in production for several years.
+
+### Requirements
+
+* PHP >= 5.4
+* [PHP GD](https://secure.php.net/manual/en/book.image.php)
 
 ### How do I use this?
 
-Simply clone the repository and travel to ``/barcode.php``. You will get a random barcode. If you want a specific one, go to ``/barcode.php?code=`` and input a 12 digit number.
+The signatures are fairly simple. Simply call `barcode` with the number of the
+barcode and the scale of the barcode as an integer. The number needs to be
+either 12 or 13 digits. The barcode will always be 13 digits even if only 12
+are supplied as the 13th digit is the checksum of the first 12. The barcode's
+scale will not go lower than 2 for scaling reasons and no higher than 12 for
+memory reasons. A scale of 4 has worked well for my purposes in the past.
+
+    $barcode = new Barcode(1349875921348, 4);
+    $barcode = new Barcode(439457143245, 10);
+
+The key thing to keep up with is the `FreeSansBold.ttf` file. By default the
+Barcode class will look into PHP's calling directory for the font file. You can
+specify a path as a third parameter.
+
+    $barcode = new Barcode(123456789120, 4, "/path/to/FreeSansBold.ttf");
+
+There are only two public methods: `image()` and `display()`. The first
+function `image()` returns the PHP created image as a reference. This may be
+used to save an image to file, e.g. `imagepng($barcode->image(),
+"/path/to/storage/barcode.png")`. The second function `display()` simply calls
+the correct headers and displays the barcode in the browser. Useful for
+debugging.

barcode.php

@@ -1,38 +1,244 @@
 <?php
-//autoload
-include("ean.php");
+
+/*
+ * Create an EAN13 Barcode image.
+ */
 
 class Barcode
 {
+   public $font;
    public $number;
-   public $encoding;
    public $scale;
 
-   protected $_encoder;
+   private $_key;
+   private $_bars;
+
+   private $_image;
+   private $_width;
+   private $_height;
+
+   public static $PARITY_KEY = array(
+      0 => "000000", 1 => "001011", 2 => "001101", 3 => "001110",
+      4 => "010011", 5 => "011001", 6 => "011100", 7 => "010101",
+      8 => "010110", 9 => "011010"
+   );
+
+   public static $LEFT_PARITY = array(
+      // Odd Encoding
+      0 => array(
+          0 => "0001101", 1 => "0011001", 2 => "0010011", 3 => "0111101",
+          4 => "0100011", 5 => "0110001", 6 => "0101111", 7 => "0111011",
+          8 => "0110111", 9 => "0001011"
+      ),
+      // Even Encoding
+      1 => array ( 
+          0 => "0100111", 1 => "0110011", 2 => "0011011", 3 => "0100001", 
+          4 => "0011101", 5 => "0111001", 6 => "0000101", 7 => "0010001", 
+          8 => "0001001", 9 => "0010111"
+       )
+   );
+
+   public static $RIGHT_PARITY = array(
+      0 => "1110010", 1 => "1100110", 2 => "1101100", 3 => "1000010", 
+      4 => "1011100", 5 => "1001110", 6 => "1010000", 7 => "1000100", 
+      8 => "1001000", 9 => "1110100"
+   );
 
-   function __construct($encoding, $number=null, $scale=null)
+   public static $GUARD = array(
+      'start' => "101", 'middle' => "01010", 'end' => "101"
+   );
+
+   public static function checksum (string $ean) {
+      $even=true; $esum=0; $osum=0;
+      for ($i = strlen($ean)-1; $i >= 0; $i--) {
+         if ($even) $esum+=$ean[$i]; else $osum+=$ean[$i];
+            $even=!$even;
+      }
+      return (10-((3*$esum+$osum)%10))%10;
+   }
+
+   /**
+    * Create the barcode. $number is the 12/13 digit barcode to be displayed.
+    * The $scale is the scale of the image in integers. The scale will not go
+    * lower than 2 or greater than 12.
+    */
+
+   public function __construct (string $number, $scale, $fontpath=null)
    {
-      $this->number = ($number==null) ? $this->_random() : $number;
-      $this->scale = ($scale==null || $scale<4) ? 4 : $scale;
+      /* Get the parity key, which is based on the first digit. */
+      $this->_key = self::$PARITY_KEY[substr($number,0,1)];
+
+      if (!$fontpath)
+          $this->font = dirname(__FILE__) . "/" . "FreeSansBold.ttf";
+      else
+          $this->font = $fontpath;
 
-      // Reflection Class : Method
+      /* Clamp scale between 2 and 12 */
+      if ($scale < 2)
+          $this->scale = 2;
+      else if ($scale > 12)
+          $this->scale = 12;
+      else
+          $this->scale = $scale;
 
-      $this->_encoder = new EAN13($this->number, $this->scale);
+      $len = strlen($number);
+      if ($len != 13 && $len != 12)
+          trigger_error('Barcode expects 12 or 13 digit number', E_USER_ERROR);
+
+      /* The checksum (13th digit) can be calculated or supplied */
+      $this->number = $number;
+      if ($len === 12)
+          $this->number .= self::checksum($number);
+
+      $this->_bars = $this->_encode();
+      $this->_createImage();
+      $this->_drawBars();
+      $this->_drawText();
    }
 
-   function __destruct()
+   public function __destruct()
    {
-      $this->_encoder->display();
+      imagedestroy($this->_image);
    }
 
-   private function _random()
+   /**
+    * The following incantations use the parity key (based off the 
+    * first digit of the unencoded number) to encode the first six
+    * digits of the barcode. The last 6 use the same parity.
+    *
+    * So, if the key is 010101, the first digit (of the first six
+    * digits) uses odd parity encoding. The second uses even. The
+    * third uses odd, and so on.
+    */
+
+   protected function _encode()
    {
-     return substr(number_format(time() * rand(),0,'',''),0,12);
+      $barcode[] = self::$GUARD['start'];
+      for($i=1;$i<=strlen($this->number)-1;$i++)
+      {
+         if($i < 7)
+            $barcode[] = self::$LEFT_PARITY[$this->_key[$i-1]][substr($this->number, $i, 1)];
+         else
+            $barcode[] = self::$RIGHT_PARITY[substr($this->number, $i, 1)];
+         if($i == 6)
+            $barcode[] = self::$GUARD['middle'];
+      }
+      $barcode[] = self::$GUARD['end'];
+      return $barcode;
    }
-}
 
-$encoding = (isset($_GET['encoding'])) ? $_GET['encoding'] : 'EAN-13';
-$number   = (isset($_GET['code']))     ? $_GET['code']     : null;
-$scale    = (isset($_GET['scale']))    ? $_GET['scale']    : null;
+   /**
+    * Create the image.
+    *
+    * The Height is 60 times the scale and the width is simply 
+    * 180% of the height.
+    */
+
+   protected function _createImage()
+   {
+      $this->_height = $this->scale * 60;
+      $this->_width  = 1.8 * $this->_height;
+      $this->_image = imagecreate($this->_width, $this->_height);
+      ImageColorAllocate($this->_image, 0xFF, 0xFF, 0xFF);
+   }
+
+   /**
+    * Draw the actual bars themselves.
+    *
+    * We have defined some constants. MAX is the y-value for the maximum
+    * height a bar should go. FLOOR is the y-value for the minimum height.
+    *
+    * The differences in margin for MAX and FLOOR are because most of the 
+    * barcode doesn't extend to the bottom, only the guards do.
+    *
+    * WIDTH is the actual width of the bars.
+    *
+    * X is the starting position of the bars, which is a fifth of the way
+    * into the image.
+    *
+    * To draw the bars, we translate a binary string into bars:
+    *
+    * 10111001 - bar, empty, bar, bar, bar, empty, empty, bar
+    */
+
+   protected function _drawBars()
+   {
+      $bar_color=ImageColorAllocate($this->_image, 0x00, 0x00, 0x00);
+
+      $MAX   = $this->_height*0.025;
+      $FLOOR = $this->_height*0.825;
+      $WIDTH = $this->scale;
+
+      $x = ($this->_height * 0.2) - $WIDTH;
+
+      foreach($this->_bars as $bar)
+      {
+         $tall = 0;
+
+         if(strlen($bar)==3 || strlen($bar)==5)
+            $tall = ($this->_height * 0.15);
+
+         for($i = 1; $i <= strlen($bar); $i++)
+         {
+            if(substr($bar, $i-1, 1)==='1')
+                imagefilledrectangle($this->_image, $x, $MAX, $x + $WIDTH, 
+                    $FLOOR + $tall, $bar_color);
+            $x += $WIDTH;
+         }
+      }
+   }
+
+   /**
+    * Draw the text:
+    *
+    * The first digit is left of the first guard. The kerning
+    * is how much space is in between the individual characters.
+    *
+    * We add kerning after the first character to skip over the
+    * first guard. Then we do it again after the 6th character
+    * to skip over the second guard.
+    *
+    * We don't need to skip over the last guard.
+    *
+    * The fontsize is 7 times the scale.
+    * X is the start point, which is .05 a way into the image
+    */
+
+   protected function _drawText()
+   {
+      $x = $this->_width*0.05;
+      $y = $this->_height*0.96;
+
+      $text_color=ImageColorAllocate($this->_image, 0x00, 0x00, 0x00);
+
+      $fontsize = $this->scale*7;
+      $kerning = $fontsize*1;
 
-new Barcode($encoding, $number, $scale);
+      for($i=0;$i<strlen($this->number);$i++)
+      {
+         imagettftext($this->_image, $fontsize, 0, $x, $y, $text_color, $this->font, $this->number[$i]);
+         if($i==0 || $i==6)
+            $x += $kerning*0.5;
+         $x += $kerning;
+      }
+   }
+
+   /**
+    * Return the barcode's image by reference.
+    */
+
+   public function &image()
+   {
+      return $this->_image;
+   }
+
+   /**
+    * Send the headers and display the barcode.
+    */
+
+   public function display()
+   {
+      header("Content-Type: image/png; name=\"barcode.png\"");
+      imagepng($this->_image);
+   }
+}