note 99623 added to function.imagecreatetruecolor

HOW THE CHECK THE MEMORY BEFORE CREATING AN IMAGE? I worked on a script where I delt with large images. Very often the error "out of memory" occured. So I had to figure out, how to check the memory BEFORE creating an image. I didn't find a solution on the web, so I ran my own test script. It built lots of images to compute the needed memory. I found out, that the formula mem = x * y * channel was not enough. There was an additional multiplier that varied. As a result 1.7 worked best. So the formula is: mem = x * y * channel * 1.7. I post this script here hoping it is useful to someone who will run into the same problems. <?php //-------------------------------------------------- DEFINE MAXMEM define ("MAXMEM", 32*1024*1024); //--- memory limit (32M) --- //-------------------------------------------------- ENOUGH MEMORY ? function enoughmem ($x, $y, $rgb=3) { return ( $x * $y * $rgb * 1.7 < MAXMEM - memory_get_usage() ); } //-------------------------------------------------- SIMPLE EXAMPLE list ($x, $y) = @getimagesize ('your_img.jpg'); //--- get size of img --- if (enoughmem($x,$y)) { $img = @imagecreatefromjpeg ('your_img.jpg'); //--- open img file --- $thumb = 200; //--- max. size of thumb --- if ($x > $y) { $tx = $thumb; //--- landscape --- $ty = round($thumb / $x * $y); } else { $tx = round($thumb / $y * $x); //--- portrait --- $ty = $thumb; } if (enoughmem($tx,$ty)) { $thb = imagecreatetruecolor ($tx, $ty); //--- create thumbnail --- imagecopyresampled ($thb,$img, 0,0, 0,0, $tx,$ty, $x,$y); imagejpeg ($thb, 'your_thumbnail.jpg', 80); imagedestroy ($thb); } imagedestroy ($img); } //-------------------------------------------------- //--- to check the memory working with --- //--- b/w-image or gif use: --- //-------------------------------------------------- $check = enoughmem ($x, $y, 1); ?> Taking the opportunity, I thank everyone here at php.net for the great manual and the useful user scripts. ---- Server IP: 217.160.235.204 Probable Submitter: 79.208.164.244 ---- Manual Page -- http://www.php.net/manual/en/function.imagecreatetruecolor.php Edit -- https://master.php.net/note/edit/99623 Del: integrated -- https://master.php.net/note/delete/99623/integrated Del: useless -- https://master.php.net/note/delete/99623/useless Del: bad code -- https://master.php.net/note/delete/99623/bad+code Del: spam -- https://master.php.net/note/delete/99623/spam Del: non-english -- https://master.php.net/note/delete/99623/non-english Del: in docs -- https://master.php.net/note/delete/99623/in+docs Del: other reasons-- https://master.php.net/note/delete/99623 Reject -- https://master.php.net/note/reject/99623 Search -- https://master.php.net/manage/user-notes.php