[Resolved] Imagecreate help :)

[jonno946]

i'm making a spam protection feature for my website, however i have a strange problem.

here is my script:

<?php

function random_number($min, $max) {

// make random number

$number = mt_rand($min, $max);

// return random number

return $number;

}

function make_image() {

// make the image

$base_image = imagecreate(150,40);

// Allocate two colors (Black & White)

// This uses the RGB names of the colors

$color_black = imagecolorallocate($base_image, random_number(1, 125), random_number(1, 125), random_number(1, 125));

$color_white = imagecolorallocate($base_image, random_number(175, 255), random_number(175, 255), random_number(175, 255));

// Flood Fill our image with black

imagefill($base_image, 0, 0, $color_black);

// generate random number

$random_number = random_number(100000, 999999);

// insert random number onto image

imagechar($base_image, random_number(1, 5), random_number(1, 20), random_number(1, 25), $random_number[0], $color_white);
imagechar($base_image, random_number(1, 5), random_number(20, 40), random_number(1, 25), $random_number[1], $color_white);
imagechar($base_image, random_number(1, 5), random_number(40, 60), random_number(1, 25), $random_number[2], $color_white);
imagechar($base_image, random_number(1, 5), random_number(60, 100), random_number(1, 25), $random_number[3], $color_white);
imagechar($base_image, random_number(1, 5), random_number(100, 120), random_number(1, 25), $random_number[4], $color_white);
imagechar($base_image, random_number(1, 5), random_number(120, 140), random_number(1, 25), $random_number[5], $color_white);

// echo image

header("Content-type: image/jpeg");

imagejpeg($base_image);

}

echo make_image();

?>

All works fine if i change:

$random_number = random_number(100000, 999999);

to

$random_number = 999999;

why is it not letting me do the same with a random number?!?

Thanks

Jonathan

[Weedpacket]

It seems imagechar won't except anything other than a string as its fifth argument - it won't cast integers to strings (its signature in the manual specifies "string", not "mixed"). $random_number=999999; doesn't work for me, but $random_number='999999' and $random_number = ''.mt_rand(100000,999999); do.

[jonno946]

ahh well spotted, works a treat 🙂

Thanks!

[Installer]

Well spotted is exactly right. Good job, Weedpacket

[Weedpacket]

Thanks. 'Course, what I wanna know is why normal casting rules aren't applied?

So I did a bit of poking and prodding.

Ah-ha! The casting rules were being applied, but too late!

$number = '99999';
$number[0] (or, strictly speaking, $number{0}) is the character '9'.

$number = 99999;
$number[0] is empty, because $number is not a string.

From that point on, all imagechar() sees are empty strings.

So I guess indexing characters in numbers is a no-no. Learn something new every day, me.

I guess if it was allowed there'd be trouble:

$n = .1;
echo $n{0};

Should that output '.' or '0'?

What about $n{14}? If you configure PHP to show sufficient decimal places in its floating point numbers (22 or so), you'd see that .1 gets stored as 0.10000000000000001 because of floating-point roundoff. So does that mean $n{14} should be '0' as well?

[Installer]

Once again, good stuff. Thanks.