Making pie chart

NZ_Kiwis

I have 3 results,

total = 10
green = 6
red = 2

I want to make a pie chart with 60% being green 40% being red... can this be done.. the % will always change....

brandtj

This ought to do it. 😃

<?php

$radius = 100;

$p_green = 60;
$p_red = 40;

$image = @imagecreate (2 * $radius + 1, 2 * $radius + 1);

$white = @imagecolorallocate ($image, 255, 255, 255);
$black = @imagecolorallocate ($image, 0, 0, 0);

$green = @imagecolorallocate ($image, 0, 255, 0);
$red = @imagecolorallocate ($image, 255, 0, 0);

@imagefilledrectangle ($image, 0, 0, 2 * $radius + 1, 2 * $radius + 1, $white);

@imagefilledarc ($image, $radius, $radius, 2 * $radius, 2 * $radius, 0, 3.6 * $p_green, $green, IMG_ARC_PIE);
@imagefilledarc ($image, $radius, $radius, 2 * $radius, 2 * $radius, 3.6 * $p_green, 360, $red, IMG_ARC_PIE);

@imageellipse ($image, $radius, $radius, 2 * $radius, 2 * $radius, $black);

header ('Content-type: image/png');
@imagepng ($image);

@imagedestroy ($image);

?>

(Note that the $p_red variable is never actually used... theoretically you only need to supply $p_green.)

If you find any bugs please let me know... I think I'll add this one to my library of scripts I'm proud of. This will be the first. 😛

barand

To make it more reuseable, change the percent value definitions to get values from querystring.

Save as "mypie.php"

<?php

$radius = 100;

$p_green = $_GET['g'];
$p_red =  $_GET['r'];

$image = @imagecreate (2 * $radius + 1, 2 * $radius + 1);

$white = @imagecolorallocate ($image, 255, 255, 255);
$black = @imagecolorallocate ($image, 0, 0, 0);

$green = @imagecolorallocate ($image, 0, 255, 0);
$red = @imagecolorallocate ($image, 255, 0, 0);

@imagefilledrectangle ($image, 0, 0, 2 * $radius + 1, 2 * $radius + 1, $white);

@imagefilledarc ($image, $radius, $radius, 2 * $radius, 2 * $radius, 0, 3.6 * $p_green, $green, IMG_ARC_PIE);
@imagefilledarc ($image, $radius, $radius, 2 * $radius, 2 * $radius, 3.6 * $p_green, 360, $red, IMG_ARC_PIE);

@imageellipse ($image, $radius, $radius, 2 * $radius, 2 * $radius, $black);

header ('Content-type: image/png');
@imagepng ($image);

@imagedestroy ($image);
?>

and place on your page with

<?php
echo '<IMG src="mypie.php?g=60&r=40">';
?>

brandtj

Good plan! In fact, if you do it that way--quite clever--then I would recommend taking out the $p_red variable, since it's useless. Take it out from the script, and then change the GET variable to something more pratical like bal for "balance", showing where the balance of the pie chart is. So the new code would be:

$p_green = $_GET['bal'];

<img src="./mypie.php?bal=60">

Just spitballin' here, haha.

barand

In the original post the figures were

total = 10
green = 6
red = 2

So you may want the red value(20% according to those figures) and also show unused segment (also 20%) but a change in code would be required to use red value too. This is left as an exercise for the reader :-)

NZ_Kiwis

Can I label each one at all??

brandtj

I would think that labeling them would take an extreme amount of math... because you would have to calculate the bbox size, shrink it accordingly, place them in opportune places, and generally a ton more stuff.

I'm bored, I'll play around with it... but is it fairly important that they are labeled?

dougal85

labels are vital to all pies! 😛

NZ_Kiwis

brandtj wrote:
I would think that labeling them would take an extreme amount of math... because you would have to calculate the bbox size, shrink it accordingly, place them in opportune places, and generally a ton more stuff.

I'm bored, I'll play around with it... but is it fairly important that they are labeled?

Cool thanks so much

brandtj

Sure it's not a problem... This is something very quick that I whipped up:

<?php

$radius = 100;

$p_green = 30;

$image = @imagecreate (2 * $radius + 1, 2 * $radius + 1);

$white = @imagecolorallocate ($image, 255, 255, 255);
$black = @imagecolorallocate ($image, 0, 0, 0);

$green = @imagecolorallocate ($image, 0, 255, 0);
$red = @imagecolorallocate ($image, 255, 0, 0);

@imagefilledrectangle ($image, 0, 0, 2 * $radius + 1, 2 * $radius + 1, $white);

@imagefilledarc ($image, $radius, $radius, 2 * $radius, 2 * $radius, 0, 3.6 * $p_green, $green, IMG_ARC_PIE);
@imagefilledarc ($image, $radius, $radius, 2 * $radius, 2 * $radius, 3.6 * $p_green, 360, $red, IMG_ARC_PIE);

$text_g = @imagettfbbox (10, 0, './arial.ttf', $p_green . '%');
@imagettftext ($image, 10, 0, 170, 180 - $text_g[7], $black, './arial.ttf', $p_green . '%');

$text_r = @imagettfbbox (10, 0, './arial.ttf', (100 - $p_green) . '%');
@imagettftext ($image, 10, 0, 30 - $text_r[2], 20, $black, './arial.ttf', (100 - $p_green) . '%');

@imageellipse ($image, $radius, $radius, 2 * $radius, 2 * $radius, $black);

header ('Content-type: image/png');
@imagepng ($image);

@imagedestroy ($image);

?>

Now the downside to this code is that it always puts the numbers in the same place (and of course, you could put a name in that place rather than the percentage)... so if the green portion is only 5%, both labels will "look like" they're labeling the red section.

dougal85

i dont know how to label them - but would an easier solution not be... make the image a bit wider and do like a legend at the side.

rather than trying to get the label on the pie.

Might look better aswell tbh.

Just a thought.

barand

You might want to have a look at the baaChart link in my sig.

Pie charts with labels and/or legends

jonki

I have this working great (thanks a lot for the postings) but if I want to send variables from the 1st page it doesnt work:

This works;

echo '<IMG src="mypie.php?a=10&b=10&c=20">';

This doesnt;

$a=10;
$b=20;
$c= 25;
$otros=100-($a+$b+$c);

echo '<IMG src="mypie.php?a=$a&b=$b&c=$c">';

Can anyone tell me why not and give me a clue of how tto get around it?

Many thanks

barand

try

$a = $_GET['a];

etc

jonki

Many thanks for your help. I have already tried that .. and tried it again at your suggestion but it doesn't work.

barand

As you only pass a, b, and c, you need to calculate

$otros=100-($a+$b+$c);

inside mypie.php

dougal85

echo '<IMG src="mypie.php?a='.$a.'&b='.$b.'&c='.$c.'">';

try that, remember you cant use variable names directly between single quotes.

jonki

THAT'S IT!! FANTASTIC. Solved all the problems.
Many many thanks!