how can i change the dpi of an image with the imagick extension

Question

I need to change all uploaded files to 72 dpi. I\'m using the php imagick extension.

heres what i\'ve tried (the image i\'m using is 300dpi):

$image          


        

Answer 1

MatTheCat's answer is spot on. You might also try setImageUnits() to ensure it's working with inches and not centimeters.

$image->setImageUnits(imagick::RESOLUTION_PIXELSPERINCH);
$image->setImageResolution(72,72);

Resampling isn't necessary just to change dpi.

Note that changing the dpi alone will not affect file size and only applies to resampling and printing.

Answer 2

It seems you have to use setImageResolution rather than setResolution : http://www.php.net/manual/fr/function.imagick-setresolution.php#95533