php-GD image calculate memory usage

Hi all,

I'm using GD library version 2.0.28 for resizing images on my server. As
I've checked out, the maximum allowed memory (16MB) is reached when my
original picture is 2158*1618 pixels. For now I just check the width and
height of the pictures and if there is one bigger than 1900 pixels I don't
try to resize and do it with an other program.

Now the memory limit has been raised by the hosting company (This setting
can't be changed in any way since the hosting company did disallow all ways
to do so).
I can now deal with 50MB memory limit. I'd like to know how to check the
needed memory for resizing and the maximum allowed memory the script can
deal with...like

if(neededmemory > availablememory)
resizepicture
else
tagpicturetoberesized

How to check the neededmemory and availablememory ?
neededmemory is the memory I need to load the original file and resize it
(imagecreatefromjpeg for the original and imagecreatetruecolor for the
copy).

Thanks for helping.

Bob

Re: php-GD image calculate memory usage

..oO(Bob Bedford)

>I'm using GD library version 2.0.28 for resizing images on my server. As
>I've checked out, the maximum allowed memory (16MB) is reached when my
>original picture is 2158*1618 pixels. For now I just check the width and
>height of the pictures and if there is one bigger than 1900 pixels I don't
>try to resize and do it with an other program.
>
>Now the memory limit has been raised by the hosting company (This setting
>can't be changed in any way since the hosting company did disallow all ways
>to do so).
>I can now deal with 50MB memory limit. I'd like to know how to check the
>needed memory for resizing and the maximum allowed memory the script can
>deal with...like
>
>if(neededmemory > availablememory)
> resizepicture
>else
> tagpicturetoberesized
>
>How to check the neededmemory and availablememory ?

With ini_get() you can get the value of the memory_limit directive.

A quite good estimation of the needed memory for an image in bytes is to
calculate the number of pixels and multiply that value with 4 (3 bytes
for the RGB colors, 1 byte for the alpha channel).

Micha