Adding a graph

randombar · 28-09-2007 1:18pm #1

Lads,
Looking for a bit of direction here where I want to add a persons score to a bell curve, i.e. show graphically his score against a bell curve?
Thanks
Gary

forbairt · 28-09-2007 1:30pm

do you need to generate the original bell curve ?

Is this just to add a point to a graph ?

There are librarys that can do nice things for you ... usually commercial though ...

otherwise doing it yourself ...
http://www.php.net/manual/en/function.imagecreate.php

forbairt · 28-09-2007 1:32pm

from someones example on the page I linked to ...

// A simple XY graph

<html>
<head>
       
 <title>XY Graph</title>

<h2>Practice XY Graph</h2>
</head>
<body>

<?php
$left = 0;
$top = 0;
$x_size = 400;
$y_size = 400;

$char_width = 8;
$char_height = 11;

$x_start = $x_left + 100;
$y_start = $top + $char_height * 1.5;
$x_end = $x_start + $x_size;
$y_end = $y_start + $y_size;
$right = $x_start + $x_size + 40;
$bottom = $y_start + $y_size + $char_height * 1.5;

$graph_n = 100;
for($i = 0; $i < $graph_n; $i++ )
    {
    $graph_x[$i] = $i;
    $graph_y[$i] = $i * $i;
    }

    $min_x = 9e99;
    $min_y = 9e99;
    $max_x = -9e99;
    $max_y = -9e99;

    $avg_y = 0.0;
   
    for($i = 0; $i < $graph_n; $i++ )
        {
        if( $graph_x[$i] < $min_x )
            $min_x = $graph_x[$i];

        if( $graph_x[$i] > $max_x )
            $max_x = $graph_x[$i];

        if( $graph_y[$i] < $min_y )
            $min_y = $graph_y[$i];

        if( $graph_y[$i] > $max_y )
            $max_y = $graph_y[$i];

        $avg_y += $graph_y[$i];
        }
   
    $avg_y = $avg_y / $graph_n;

    $min_x = 0;
    $min_y = 0;
    $max_x += $max_x * 0.05;
    $max_y += $max_y * 0.05;

$image = ImageCreate($right - $left, $bottom - $top);
$background_color = imagecolorallocate($image, 255, 255, 255);
$text_color = imagecolorallocate($image, 233, 14, 91);

$grey = ImageColorAllocate($image, 204, 204, 204);
$white = imagecolorallocate($image, 255, 255, 255);
$black = imagecolorallocate($image, 0, 0, 0);
$red = imagecolorallocate($image, 255, 0, 0);

imagerectangle($image, $left, $top, $right - 1, $bottom - 1, $black );
imagerectangle($image, $x_start, $y_start, $x_end, $y_end, $grey );

for($i = 0; $i < $graph_n; $i++ )
   {
   $pt_x = $x_start + ($x_end-$x_start)*($graph_x[$i]-$min_x)/($max_x-$min_x);
   $pt_y = $y_end - ($y_end - $y_start)*($graph_y[$i]-$min_y)/($max_y-$min_y);

 //  imagesetpixel( $image, $pt_x, $pt_y, $black );
   imagechar($image, 2, $pt_x - 3, $pt_y - 10, '.', $black);
   }

$string = sprintf("%2.5f", $max_y);
imagestring($image, 4, $x_start - strlen($string) * $char_width, $y_start - $char_width, $string, $black);

$string = sprintf("%2.5f", $min_y);
imagestring($image, 4, $x_start - strlen($string) * $char_width, $y_end - $char_height, $string, $black);

$string = sprintf("%2.5f", $min_x);
imagestring($image, 4, $x_start - (strlen($string) * $char_width)/2, $y_end, $string, $black);
   
$string = sprintf("%2.5f", $max_x);
imagestring($image, 4, $x_end - (strlen($string) * $char_width) / 2, $y_end, $string, $black);

$x_title = 'x axis';
$y_title = 'y axis';

imagestring($image, 4, $x_start + ($x_end - $x_start) / 2 - strlen($x_title) * $char_width / 2, $y_end, $x_title, $black);

imagestring($image, 4, $char_width, ($y_end - $y_start) / 2, $y_title, $black);

header('Content-type: image/png');
$filename = sprintf("%d.png", time());
ImagePNG($image,$filename);
ImageDestroy($image);

printf("<img src='%s'> ", $filename);
?>

</body>
</html>

randombar · 28-09-2007 1:41pm

I guess I'd like to have the point on/over a generic bell curve to start off?

A Problem with the script above is you're writing to a folder (security issues?)

daymobrew · 28-09-2007 1:42pm

forbairt wrote:

There are libraries that can do nice things for you ... usually commercial though ...

One of those in PHP/SWF Charts (it is free to download and use). Very slick and easy.

forbairt · 28-09-2007 1:53pm

daymobrew wrote:

One of those in PHP/SWF Charts (it is free to download and use). Very slick and easy.

Its a commercial license though unless its only for personal stuff ... its also a flash file so you can't save it to disk

forbairt · 28-09-2007 1:53pm

GaryCocs wrote:

A Problem with the script above is you're writing to a folder (security issues?)

No security issues ... assuming you've got good security

di11on · 28-09-2007 10:30pm

Wouldn't an easy enough way of doing this to be... find/generate an image for your generic bell curve.

Then use this image as the backgorund image for a table.

Then you just need to create 4 cells in your table and place your "point" image in the bottom right hand corner of the top left cell. Then it's just a matter of working out the height and width of the top left cell.

Would this work?

Adding a graph

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