Image DPI with GD

Jak-S

Hi,

I am currently using imagesx and imagesy to get the dimensions of an image. How do i also get the DPI (Horizontal and Vertical resolutions) of the image?

I have a horrible feeling that this cant be done (because i cant find anywhere that tells you how to do it). However i really need it.

Thanks in advance,

bpat1434

Perhaps with [man]imagecolorstotal/man you might be able to throw something together to where if the total colors are between 1 and 256 it's 8-bit, 257 and 512 it's 16-bit, 513 and above it's 32-bit....

But I know imageMagick has the ability to do it, so if you can get that, I'd try. Plus imageMagick is superior to GD anyway...

~Brett

Jak-S

Sorry, its not the bit depth were looking for, its the dpi, like 72dpi, 96dpi, 300dpi e.t.c. The horizontal and vertical resolutions that are used for printing the image.

Jasp182

Install ImageMagick on your server, and you can use the identify command. If you're working alot with images in php, chances are you'll run into situations that GD alone can't handle. Here's an example of how I would probably do it with a shell call to ImageMagick:

$shell_command = 'identify -format "%x,%y" /path/to/image';
$resolution = array();
$resolution = explode(',' , shell_exec($shell_command));
$res_x = $resolution[0];
$res_y = $resolution[1];

{edit}

whoops...forgot the links:

ImageMagick identify command

-format argument