suggestion for increasing performance

[GoogleCodeExporter]

As the source code isn't editable by me, I'll use the "submit issue" for 
some suggestions. Especially my first suggestion will dramatically improve 
rendering speed (for large csv files by a full second on slow server). 

1. Line 3018. The count function will be executed for every loop cycle. 
This means, for a csv file with 300 lines, each line a label and 3 date 
points, the count function will be executed 135450 times. Simply putting 
the count outside the for-loop will do the trick. 

for($i = 0; $i <= count($Plots) - 4; $i += 2) {
// do some stuff
}

will be

$Count = count($Plots);
for($i = 0; $i <= $count - 4; $i += 2) {
// do some stuff
}

2. Seriously consider changing all the usings of floor into typecasting 
with (int)$variable . 

For example, line 4399. Also a rewrite of the if else a few lines beneath. 
So line 4398-4422 could be changed to: 

$Plot = array();
$Xi   = (int)$X; 
     $Yi   = (int)$Y; 

      if ( $Xi == $X && $Yi == $Y) 
       { 
// .. 
       } 
      else 
       { 
          $xdiff = ($X - $Xi); 
          $ydiff = ($Y - $Yi); 
       $Alpha1 = (((1 - $xdiff) * (1 - $ydiff) * 100) / 100) * $Alpha; 
        if ( $Alpha1 > $this->AntialiasQuality ) { $this->drawAlphaPixel
($Xi,$Yi,$Alpha1,$R,$G,$B); } 

       $Alpha2 = (($xdiff * (1 - $ydiff) * 100) / 100) * $Alpha; 
        if ( $Alpha2 > $this->AntialiasQuality ) { $this->drawAlphaPixel
($Xi+1,$Yi,$Alpha2,$R,$G,$B); } 

       $Alpha3 = (((1 - $xdiff) * $ydiff * 100) / 100) * $Alpha; 
        if ( $Alpha3 > $this->AntialiasQuality ) { $this->drawAlphaPixel
($Xi,$Yi+1,$Alpha3,$R,$G,$B); } 

       $Alpha4 = (($xdiff * $ydiff * 100) / 100) * $Alpha; 
        if ( $Alpha4 > $this->AntialiasQuality ) { $this->drawAlphaPixel
($Xi+1,$Yi+1,$Alpha4,$R,$G,$B); } 
       } 
     }

Love MTChart, keep up the good work! 

-afraca

Original issue reported on code.google.com by harkemas...@gmail.com on 22 Oct 2009 at 3:24