(PECL imagick 2, PECL imagick 3)
Imagick::setImageUnits — Sets the image units of resolution
units
Returns true on success.
You should use the PHP Imagick constants to correctly set the Image Units, as described here:
http://www.php.net/manual/en/imagick.constants.php
RESOLUTION constants
imagick::RESOLUTION_UNDEFINED (integer)
imagick::RESOLUTION_PIXELSPERINCH (integer)
imagick::RESOLUTION_PIXELSPERCENTIMETER (integer)$source = 'miphoto.jpg';
$imagick = new Imagick($source);
$imagick -> setImageUnits(2);
//0=undefined, 1=pixelsperInch, 2=PixelsPerCentimeter
$info = $imagick -> identifyImage();
print_r($info);
//ouput
/*
Array
(
[units] => PixelsPerCentimeter
)