Pie chart problem does not show if data is missing - php

Question

I have a PHP pie chart which uses data from Mysql to show the chart. However if one data is missing the whole chart turns to one color. For example for grading if the input is A, B, D and F(pay attention C grade input is missing) then the whole pie chart is in one color like Orange or red.
Can you please help me with this? Thanks
<?php
$show_label = true; // true = show label, false = don't show label.
$show_percent = true; // true = show percentage, false = don't show percentage.
$show_text = true; // true = show text, false = don't show text.
$show_parts = false; // true = show parts, false = don't show parts.
$label_form = 'square'; // 'square' or 'round' label.
$width = 199;
$background_color = 'FFFFFF'; // background-color of the chart...
$text_color = '000000'; // text-color.
$colors = array('0000ff', '006600', 'ffff00','DD7C1D', 'FF3300', 'CC6600','990000','520000','BFBFC1','808080'); // colors of the slices.
$shadow_height = 16; // Height on shadown.
$shadow_dark = true; // true = darker shadow, false = lighter shadow...
// DON'T CHANGE ANYTHING BELOW THIS LINE...
$data = $_GET["data"];
$label = $_GET["label"];
$height = $width/2;
$data = array_filter(explode('*',$data));
if ($label != '') $label = explode('*',$label);
for ($i = 0; $i < count($label); $i++)
{
if ($data[$i]/array_sum($data) < 0.1) $number[$i] = ' '.number_format(($data[$i]/array_sum($data))*100,1,',','.').'%';
else $number[$i] = number_format(($data[$i]/array_sum($data))*100,1,',','.').'%';
if (strlen($label[$i]) > $text_length) $text_length = strlen($label[$i]);
}
if (is_array($label))
{
$antal_label = count($label);
$xtra = (5+15*$antal_label)-($height+ceil($shadow_height));
if ($xtra > 0) $xtra_height = (5+15*$antal_label)-($height+ceil($shadow_height));
$xtra_width = 5;
if ($show_label) $xtra_width += 20;
if ($show_percent) $xtra_width += 45;
if ($show_text) $xtra_width += $text_length*8;
if ($show_parts) $xtra_width += 35;
}
$img = ImageCreateTrueColor($width+$xtra_width, $height+ceil($shadow_height)+$xtra_height);
ImageFill($img, 0, 0, colorHex($img, $background_color));
foreach ($colors as $colorkode)
{
$fill_color[] = colorHex($img, $colorkode);
$shadow_color[] = colorHexshadow($img, $colorkode, $shadow_dark);
}
$label_place = 5;
if (is_array($label))
{
for ($i = 0; $i < count($label); $i++)
{
if ($label_form == 'round' && $show_label)
{
imagefilledellipse($img,$width+11,$label_place+5,10,10,colorHex($img, $colors[$i % count($colors)]));
imageellipse($img,$width+11,$label_place+5,10,10,colorHex($img, $text_color));
}
else if ($label_form == 'square' && $show_label)
{
imagefilledrectangle($img,$width+6,$label_place,$width+16,$label_place+10,colorHex($img, $colors[$i % count($colors)]));
imagerectangle($img,$width+6,$label_place,$width+16,$label_place+10,colorHex($img, $text_color));
}
if ($show_percent) $label_output = $number[$i].' ';
if ($show_text) $label_output = $label_output.$label[$i].' ';
if ($show_parts) $label_output = $label_output.$data[$i];
imagestring($img,'2',$width+20,$label_place,$label_output,colorHex($img, $text_color));
$label_output = '';
$label_place = $label_place + 15;
}
}
$centerX = round($width/2);
$centerY = round($height/2);
$diameterX = $width-4;
$diameterY = $height-4;
$data_sum = array_sum($data);
$start = 270;
for ($i = 0; $i < count($data); $i++)
{
$value += $data[$i];
$end = ceil(($value/$data_sum)*360) + 270;
$slice[] = array($start, $end, $shadow_color[$value_counter % count($shadow_color)], $fill_color[$value_counter % count($fill_color)]);
$start = $end;
$value_counter++;
}
for ($i=$centerY+$shadow_height; $i>$centerY; $i--)
{
for ($j = 0; $j < count($slice); $j++)
{
ImageFilledArc($img, $centerX, $i, $diameterX, $diameterY, $slice[$j][0], $slice[$j][1], $slice[$j][2], IMG_ARC_PIE);
}
}
for ($j = 0; $j < count($slice); $j++)
{
ImageFilledArc($img, $centerX, $centerY, $diameterX, $diameterY, $slice[$j][0], $slice[$j][1], $slice[$j][3], IMG_ARC_PIE);
}
OutputImage($img);
ImageDestroy($img);
function colorHex($img, $HexColorString)
{
$R = hexdec(substr($HexColorString, 0, 2));
$G = hexdec(substr($HexColorString, 2, 2));
$B = hexdec(substr($HexColorString, 4, 2));
return ImageColorAllocate($img, $R, $G, $B);
}
function colorHexshadow($img, $HexColorString, $mork)
{
$R = hexdec(substr($HexColorString, 0, 2));
$G = hexdec(substr($HexColorString, 2, 2));
$B = hexdec(substr($HexColorString, 4, 2));
if ($mork)
{
($R > 99) ? $R -= 100 : $R = 0;
($G > 99) ? $G -= 100 : $G = 0;
($B > 99) ? $B -= 100 : $B = 0;
}
else
{
($R < 220) ? $R += 35 : $R = 255;
($G < 220) ? $G += 35 : $G = 255;
($B < 220) ? $B += 35 : $B = 255;
}
return ImageColorAllocate($img, $R, $G, $B);
}
function OutputImage($img)
{
header('Content-type: image/jpg');
ImageJPEG($img,NULL,100);
}
?>