Errata

The code on graphics in 'introduction to PHP' section where it says "a text entry field that lets the user specify the text for a button. It takes an empty button image file, and centers the text passed as the GET parameter 'message' on it. The result is then sent back to the browser as a PNG image." this gives numerous warning and fatal errors as the code has huge amount of bugs, this is just one of the warnings given...Warning: imagettfbbox(): Invalid font filename in C:\wamp64\www\button.php on line 7, please let me know how to fix this as this a bug from the book.

The code on graphics in 'introduction to PHP Example 1-5' section where it says "a text entry field that lets the user specify the text for a button. It takes an empty button image file, and centers the text passed as the GET parameter 'message' on it. The result is then sent back to the browser as a PNG image." this gives numerous warning and fatal errors as the code has huge amount of bugs, this is just one of the warnings given...Warning: imagettfbbox(): Invalid font filename in C:\wamp64\www\button.php on line 7, please let me know how to fix this as this a bug from the book.

Kindle edition. The file button.png is missing. This program can't run without it. Also, as noted by another comment, $im should be $image.

On p.131, it says:

"It is generally only meaningful to use array_slice() on indexed arrays (i.e., those with consecutive integer indices starting at 0):
// this use of array_slice() makes no sense
$person = array('name' => "Fred", 'age' => 35, 'wife' => "Betty");
$subset = array_slice($person, 1, 2); // $subset is array(0 => 35, 1 => "Betty")"

However, when running this code, the output is not array(0 => 35, 1 => "Betty") but array([age] => 35, [wife] => Betty). In this case, it is meaningful to use array_slice() because the key→value pair is kept intact.

"Once the session is started, the $bg and $fg variables are created and all the script has to do is use them"But that's not what the code listing (8-14) shows. The code listing illustrates explicitly reading values from the $_SESSION array.


This one is the clearest example, but the whole section on sessions seems to have this split-brain about variable registration. The text talks about sessions as if you can register variables to be automatically loaded and saved to the session. But the example code never shows variable registration, it only shows $_SESSION array interactions.

I did a little more research on this. It looks like session registration for variables was deprecated in PHP 5.4 and removed since then. Chapter 8 looks like it was lightly rewritten to remove any explicit reference to functions like session_register(), but the text still reads as if the variable registration API exists. It's rather disconcerting in contrast to the code examples.