Question

I am trying to cut an image for small pieces from database. My code here:

$image = imagecreatefromjpeg($filename);
$width = $row['width'];
$height = $row['height'];
$new_width = 480;
$new_height = 360;          
$offset_x =  (int)(round($height*360/$width));//100
$offset_y = 0;
$new_image = imagecreatetruecolor($new_width, $new_height);
imagecopy($new_image, $image, 0, 0, $offset_x, $offset_y, $width, $height);
imagejpeg($new_image,$newimg);

But in the line $offset_x, the (int)(round($height*360/$width)) is not working. If I put an intval, like 100, all the images will cut well, but the offset position is not willing. So how to true string to int?

BTW: In this case, I will call and cut image from database in a foreach, should I unset something after this code in the foreach?

Answer 1

You rarely need to convert strings to numbers in PHP, it does that implicitely pretty well. For example, your code works just fine without any added conversions:

<?php
    $height = '100';
    $width = '200';
    $offset = round($height * 360 / $width);
    echo $offset;
?>

http://codepad.viper-7.com/LJEXIF

The problem you might be having, if it’s not giving you the right result, is the priority of operations. Your code,

round($height * 360 / $width)

Is the equivalent of

round($height * (360 / $width))

It will first divide 360 by $width, then multiply the result by $height. If that’s what you wanted, then your problem lies elsewhere. You should try and reproduce your problem with test variables on http://codepad.viper-7.com and post it back here.