Is there a way when uploading images (JPEG) to check the DPI? - php

Question

Is there a way when uploading images (JPEG) to check the DPI?
I would like to integrate it into a form, so as a validator.

Answer 1

You have to open the image with Imagick (or Gmagick) and then call getImageResolution.
$image = new Imagick($path_to_image);
var_dump($image->getImageResolution());
result:
Array
(
[x]=>75
[y]=>75
)
Edit:
For an integration into symfony, you can use a custom validator for that. You extends the default one to validate a file and add the DPI restriction.
Create this one into /lib/validator/myCustomValidatorFile .class.php:
<?php
class myCustomValidatorFile extends sfValidatorFile
{
protected function configure($options = array(), $messages = array())
{
parent::configure($options, $messages);
$this->addOption('resolution_dpi');
$this->addMessage('resolution_dpi', 'DPI resolution is wrong, you should use image with %resolution_dpi% DPI.');
}
protected function doClean($value)
{
$validated_file = parent::doClean($value);
$image = new Imagick($validated_file->getTempName());
$resolution = $image->getImageResolution();
if (empty($resolution))
{
throw new sfValidatorError($this, 'invalid');
}
if ((isset($resolution['x']) && $resolution['x'] < $this->getOption('resolution_dpi')) || (isset($resolution['y']) && $resolution['y'] < $this->getOption('resolution_dpi')))
{
throw new sfValidatorError($this, 'resolution_dpi', array('resolution_dpi' => $this->getOption('resolution_dpi')));
}
return $validated_file;
}
}
Then, inside your form, use this validator for your file:
$this->validatorSchema['file'] = new myCustomValidatorFile(array(
'resolution_dpi' => 300,
'mime_types' => 'web_images',
'path' => sfConfig::get('sf_upload_dir'),
'required' => true
));