// temperature plotting function $tra[temperature][seconds]

function plottemp(&$image, $tra, $color, $degree, $maxdegree, $line)

{

     //hate globals, but they are expedient here

    global $lbmargin, $imgwincr, $imghincr, $degperi, $tempbase, $deglines, $ror, $show_ror;

   if ($line == $show_ror)

      $ror = array(); // try and create a rate of rise

   if (count($tra) > 1)

      line_data ("-- temp$line", $color);



   $degree = $maxdegree;

   $degperi = ($degree-$tempbase) / $deglines; // offset so that the temp graph starts at 100 degrees



   for($x = 1; $x < count($tra); $x++)

   {   

//----------------------ROR Code ------------------------

      $timedelta = $tra[$x-1][1] - $tra[$x][1];

      $tempdelta = $tra[$x-1][0] - $tra[$x][0];

      if ($line == $show_ror)

         $ror[] = array(($tempdelta/$timedelta * 60), $tra[$x][1]);

//----------------------ROR Code ------------------------

      //(0,0) should be at margin, height-margin if height=400, margin=40, then 500-0/y *x = 360

      $left = $lbmargin + $tra[$x-1][1]/60*$imgwincr;

      $bot  = ($degree - $tra[$x-1][0])/ ($degperi/$imghincr);

      $right = $lbmargin + $tra[$x][1]/60*$imgwincr;

      $top  = ($degree - $tra[$x][0])/ ($degperi/$imghincr);

      imageline($image, $left, $bot+5, $right, $top+5, $color);

   }

}

for each temperature and time interval:

   current_time, and current_temperature 

   timedelta = last_time - current_time (absolute value)

   tempdelta = last_temperature - current_temperature.



   ror_current_temp = tempdelta/timedelta * 60

   ror_current_time = current_time

   add ror info to an array