<?php 

if (!defined('COLOR_HELPER_DEFINITION')){

  define('COLOR_HELPER_DEFINITION', 1);

  class ColorHelper extends Helper {

    /*
    ** the last color rgb values -- intially set to these numbers;
    */
    var $r = 191;
    var $g = 159;
    var $b = 107;

    /*
    ** the next color offset (movements -> offsets set once, and
    **                        cycled through legal values)
    */
    var $_ri = 0;
    var $_gi = 0;
    var $_bi = 0;

    /*
    ** this collects the colors we've generated from random(), in 
    ** order to prevent simple collisions.
    */
    var $used_colors = array('#ffffff');

    function ColorHelper() {

      if (!$this->_ri) {

        $this->ri = rand(15,  52);
        $this->gi = rand(17,  63);
        $this->bi = rand(19,  74);
      }
      $this->used_colors[0] = false;
    }

    /*
    ** The while loop array_search test will always fails the initial
    ** test, as we will never store the value false in the
    ** $this->used_colors array.  Thus garaunteeing a new color the
    ** first time.
    **
    ** The colors are generated by adding a randomly determined amount
    ** to each of the initial r,g,b values.  The generated values are
    ** blocked from overflow, by subtracting fixed amounts once the
    ** values pass a key threshold, these manuvers keep the colors in 
    ** a range that seems quite palatable.  Dark or black text always
    ** shows up well against these colors.
    **
    ** The return value is a css compliant hex color string, ie. 
    ** "#AB93F2".
    */
    function randomString() {

      $color = false;

      while (false !== array_search($color, $this->used_colors)) {

        $this->r += $this->ri;
        $this->g += $this->gi;
        $this->b += $this->bi;

        if (255 < $this->r) {

          $this->r -= 90;
        }
        if (223 < $this->g) {

          $this->g -= 83;
        }
        if (191 < $this->b) {

          $this->b -= 76;
        }
        $color = sprintf("#%02x%02x%02x",
                         $this->r, $this->g, $this->b);
      }
      return $color;
    }

    /*
    ** a primary use, generate random non-repeated color on invocation
    */
    function random() {

      return $this->output($this->randomString());
    }
  } // endof class ColorHelper

} // endof defined check if for Color

?>