Need a bit of help with string manipulation

Kriegster

Alright guys, I've tried a lot of things and ended up ****ing up my whole program some how. Here's what I'm trying to do: I'm trying to make a barcode reader in PHP. Now, here is my WORKING code thus far:

<?php
function getpixels($pic){
//Create a new image inside of the program to examine
$image = imagecreatefrompng($pic);
//get dimensions of said image
list($width, $height) = getimagesize($pic);
//Divides the height by 2 so that we're taking a 1 pixel slice from the MIDDLE
$height = $height/2;
$width = $width-2;
//Creats an array called vars to store the digits representing the colors across
$vars = array();
//Loops the program until it gets all the way to the end of the image
for ($i=10; $i<=$width; $i++){
  //Get's the color of the current position
  $color = imagecolorat($image, $i, $height);
  //uses array push to force the color of the current position to the end of the array
  array_push($vars, $color);
}
//Makes the function return the array
return $vars;
}
$pixls = getpixels("barcode.png");

foreach($pixls as $pixl){
echo $pixl;
}
?>

It get's the pixels across, removing a 10 pixel border, and records a white space as 0 and a black as 1. Now, what I need to do is this (and have failed miserably): I need to first remove the 2 left guard bars (represented by 2 ones seperated by a 0, may be multiple ones and multiple zeros representing thicker guard bars) then compare the first set of 7 digits to this chart:

Digit 	Pattern 	Digit 	Pattern
0 	0001101 	5 	0110001
1 	0011001 	6 	0101111
2 	0010011 	7 	0111011
3 	0111101 	8 	0110111
4 	0100011 	9 	0001011

Then the 2nd set of 7 etc., being sure to exclude the center guard bar, and convert each pod of 7 digits to a number above until I hit the right guard bar. How would I go about doing this?

Weedpacket

The elements of $pixl are going to be either 0 or 1, right? I'd actually consider putting them into a string instead of an array (I suspect the most efficient way to do this would be to return join('', $vars) instead of just $vars).

Then you can use all the string functions on what you get. preg_replace could find and remove the guard bars easily enough (sounds like /0*1{2,}0+1{2,}0+/)

Then str_split can be used to break the rest into groups of seven. After that mapping patterns to digits can just be an array lookup.

An alternative to the previous paragraph would be to use something other than 0 and 1 for the bits, and give the entire string and the mapping to strtr(); if at the end there are any bits left over then it means some pattens weren't recognised.