data2image/CharColorConverter.class.php

<?php
/**
 * This class contains some library-functions for converting a string to a color [depending on certain modes].
 * @author JPT
 */
class CharColorConverter {

	/**
	 * @var array
	 */
	protected $colortable;

	/**
	 * Default constructor.
	 * @return void
	 */
	public function __construct() {
		$this->buildColorTable();
	}

	/**
	 * Returns an array with RGB for the corresponding index.
	 * @param int $index Index from 0 to 1530. (Everything above will result the same)
	 * @return array
	 * TODO: Function to reverse this one.
	 * NOTICE: I will use 0 - 1275 for human readability;
	 */
	protected function index2rgb($index = 0) {
		$r = 255;
		$g = 0;
		$b = 0;

			//the elseif fixes a glitch.
		for($i = 0; $i < $index; $i++) {
				if($r <   255 && $g ===   0 && $b === 255) $r++;
			elseif($r === 255 && $g <   255 && $b ===   0) $g++;
			elseif($r ===   0 && $g === 255 && $b <   255) $b++;
			elseif($r >     0 && $g === 255 && $b ===   0) $r--;
			elseif($r ===   0 && $g >     0 && $b === 255) $g--;
			elseif($r === 255 && $g ===   0 && $b >     0) $b--;

			//DEBUG
			//$k = $i + 1;
			//echo "I:$k\t$r,$g,$b\r\n";
		}

		return array($r, $g, $b);
	}

	/**
	 * Creates the colortable.
	 * @return void
	 */
	protected function buildColorTable() {
		$this->colortable = array();
		for($i = 0; $i <= 1275; $i++) {
			$this->colortable[$i] = $this->index2rgb($i);
		}
	}

	/**
	 * Converts a single char to a string.
	 * @param string $string
	 * @return array RGB
	 */
	public function charToColor($string) {
		if(strlen($string) === 0) throw new Exception("Empty string given!");
		$index = ord($string) * 5;
		$color = $this->colortable[$index];
		return $color;
	}
}

?>