PHP pie chart statistics code usage

define("ANGLE_STEP", 5); //Define the angle step when drawing an elliptical arc

function draw_getdarkcolor($img,$clr) //Find the dark color corresponding to $clr
{
 $rgb = imagecolorsforindex($img,$clr);
 return array($rgb["red"]/2,$rgb["green"]/2,$rgb["blue"]/2);
}

function draw_getexy($a, $b, $d) //Find the point coordinates on the ellipse corresponding to angle $d
{
 $d = deg2rad($d);
 return array(round($a*Cos( $d)), round($b*Sin($d)));
}

function draw_arc($img,$ox,$oy,$a,$b,$sd,$ed,$clr) / /Elliptic arc function
{
 $n = ceil(($ed-$sd)/ANGLE_STEP);
 $d = $sd;
 list($x0,$y0) = draw_getexy($a,$b,$d );
 for($i=0; $i<$n; $i++)
 {
 $d = ($d+ANGLE_STEP)>$ed?$ed:($d+ANGLE_STEP);
 list($ x, $y) = draw_getexy($a, $b, $d);
 imageline($img, $x0+$ox, $y0+$oy, $x+$ox, $y+$oy, $clr);
 $ x0 = $x;
 $y0 = $y;
 }
}

function draw_sector($img, $ox, $oy, $a, $b, $sd, $ed, $clr) //Draw a sector
 {
 $n = ceil(($ed-$sd)/ANGLE_STEP);
 $d = $sd;
 list($x0,$y0) = draw_getexy($a, $b, $d);
 imageline( $img, $x0+$ox, $y0+$oy, $ox, $oy, $clr);
 for($i=0; $i<$n; $i++)
 {
 $d = ($d+ ANGLE_STEP)>$ed?$ed:($d+ANGLE_STEP);
 list($x, $y) = draw_getexy($a, $b, $d);
 imageline($img, $x0+$ox, $y0+$oy, $x+$ox, $y+$oy, $clr);
 $x0 = $x;
 $y0 = $y;
 }
 imageline($img, $x0+$ox, $y0+$oy , $ox, $oy, $clr);
 list($x, $y) = draw_getexy($a/2, $b/2, ($d+$sd)/2);
 imagefill($img, $ x+$ox, $y+$oy, $clr);
}

function draw_sector3d($img, $ox, $oy, $a, $b, $v, $sd, $ed, $clr) //3d Sector
{
 draw_sector($img, $ox, $oy, $a, $b, $sd, $ed, $clr);
 if($sd<180)
 {
 list($R, $G, $B) = draw_getdarkcolor($img, $clr);
 $clr=imagecolorallocate($img, $R, $G, $B);
 if($ed>180) $ed = 180;
 list($sx , $sy) = draw_getexy($a,$b,$sd);
 $sx += $ox;
 $sy += $oy;
 list($ex, $ey) = draw_getexy($a, $b , $ed);
 $ex += $ox;
 $ey += $oy;
 imageline($img, $sx, $sy, $sx, $sy+$v, $clr);
 imageline($img , $ex, $ey, $ex, $ey+$v, $clr);
 draw_arc($img, $ox, $oy+$v, $a, $b, $sd, $ed, $clr);
 list($sx, $sy) = draw_getexy($a, $b, ($sd+$ed)/2);
 $sy += $oy+$v/2;
 $sx += $ox;
 imagefill( $img, $sx, $sy, $clr);
 }
}

function draw_getindexcolor($img, $clr) //RBG to index color
{
 $R = ($clr>>16) & 0xff ;
 $G = ($clr>>8)& 0xff;
 $B = ($clr) & 0xff;
 return imagecolorallocate($img, $R, $G, $B);
}

// Draw the main function and output the picture
// $datLst is the data array, $datLst is the label array, $datLst is the color array
// The dimensions of the above three arrays should be equal
function draw_img($datLst, $labLst,$clrLst,$a=250,$b=120,$v=20,$font=10)
{
 $ox = 5+$a;
 $oy = 5+$b;
 $fw = imagefontwidth($font);
 $fh = imagefontheight($font);

 $n = count($datLst);//Number of data items

 $w = 10+$a*2;
 $h = 10 +$b*2+$v+($fh+2)*$n;

 $img = imagecreate($w, $h);

 //Convert RGB to index color
 for($i=0; $ i<$n; $i++)
 $clrLst[$i] = draw_getindexcolor($img,$clrLst[$i]);

 $clrbk = imagecolorallocate($img, 0xff, 0xff, 0xff);
 $clrt = imagecolorallocate($img, 0x00, 0x00, 0x00);

 //Fill the background color
 imagefill($img, 0, 0, $clrbk);

 //Sum
 $tot = 0;
 for($i =0; $i<$n; $i++)
 $tot += $datLst[$i];

 $sd = 0;
 $ed = 0;
 $ly = 10+$b*2+$v ;
 for($i=0; $i<$n; $i++)
 {
 $sd = $ed;
 $ed += $datLst[$i]/$tot*360;

 //Draw a circle Pie
 draw_sector3d($img, $ox, $oy, $a, $b, $v, $sd, $ed, $clrLst[$i]); //$sd,$ed,$clrLst[$i] );

 //Draw labels
 imagefilledrectangle($img, 5, $ly, 5+$fw, $ly+$fh, $clrLst[$i]);
 imagerectangle($img, 5, $ly, 5+ $fw, $ly+$fh, $clrt);
 //imagestring($img, $font, 5+2*$fw, $ly, $labLst[$i].":".$datLst[$i] ."(".(round(10000*($datLst[$i]/$tot))/100)."%)", $clrt);

 $str = iconv("GB2312", "UTF-8 ", $labLst[$i]);
 ImageTTFText($img, $font, 0, 5+2*$fw, $ly+13, $clrt, "./simsun.ttf", $str.":" .$datLst[$i]."(".(round(10000*($datLst[$i]/$tot))/100)."%)");
 $ly += $fh+2;
 }

 //Output graphics
 header("Content-type: image/png");

 //Output the generated image
 $imgFileName = "temp/".time().".png";
 imagepng( $img,$imgFileName);
 echo '';
}
?>

2. Calling method:

require_once ("piefunction.php");

$datLst = array(10,110,300); //Data
$labLst = array("Good review", "Medium review", "Bad review" "); //Tag
$clrLst = array(0x99ff00, 0xff6666, 0x0099ff);

draw_img($datLst,$labLst,$clrLst);
?>

Instructions: As long as the number of data is consistent with the number of subsequent labels and colors, the correct pie chart effect can be output.