CODEWITHSUNDEEP
php
Tim C
Tim C

Reputation: 5714

Creating Chart In Pure PHP Example

I have really been struggling with how to approach this problem, so I thought it would warrant it to open a new question to get some help from someone more experienced.

I am working on the following example to create a very simple chart in pure PHP http://code.web-max.ca/image_graph.php

Problem

I am adding my code, I have commented the problems I am having in the code mostly in capitals.

The problem occurs below when the $maxv variable is set to 0 which leads to an error division by zero...however when I copy and paste only the example to my editor and run it, it is working so there must be a logical problem in my code somewhere, I am attaching a screenshot aswell as my code.....any help much appreciated

IMG OF My Output enter image description here

    //create array retrieved from DB in code ABOVE and add "" and , to each value
        foreach($t1Picks as $key => $nr){
            $values[] = '"'.$nr.'"'.','; 

        }

         echo '$values are fine'. implode($values);
        echo '<br />';
    //values are fine.....go ahead

    // Get the total number of columns we are going to plot
        $columns  = count($values);
         echo 'COLUMN COUNT IS FINE'.$columns;
        echo '<br />';
    //columns count is fine continue
    // Get the height and width of the final image

        $width = 300;
        $height = 200;

    // Set the amount of space between each column

        $padding = 5;

    // Get the width of 1 column

       $column_width = $width / $columns;
       $column_width = round($column_width, 0);

       echo 'COLUMN WIDTH IS FINE'.$column_width;
       echo '<br />';
        // Generate the image variables

        $im        = imagecreate($width,$height);
        $gray      = imagecolorallocate ($im,0xcc,0xcc,0xcc);
        $gray_lite = imagecolorallocate ($im,0xee,0xee,0xee);
        $gray_dark = imagecolorallocate ($im,0x7f,0x7f,0x7f);
        $white     = imagecolorallocate ($im,0xff,0xff,0xff);

        // Fill in the background of the image

         imagefilledrectangle($im,0,0,$width,$height,$white);

       $maxv = 0; //I DONT UNDERSTAND THIS 
       //WHY MAX VAL 0? 

    // Calculate the maximum value we are going to plot

        for($i=0;$i<$columns;$i++)$maxv = max($values[$i],$maxv); //WHY NO BRACE { ON FOR 
        echo 'MAXV TEST IS'.$maxv; //THE FIRST LOOP IS 9 AND THEN ZEROS
        echo'<br />';
  // Now plot each column

Thank you very much for reading!

Upvotes: 1

Views: 293

Answers (1)

ThrowBackDewd
ThrowBackDewd

Reputation: 1767

A couple things I've noticed. It looks like you're adding a comma to each element in your $values array.

$values[] = '"'.$nr.'"'.',';

I would change that to this instead.

$values[] = $nr;

Then change your implode line to this...

echo '$values are fine'. implode(", ", $values);

Next, I don't see anyplace in your example code that you're doing division except here...

$column_width = $width / $columns;

So the only time you should get a division by zero error would be if you had no values in your $values array.

Upvotes: 1

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