上传图像(JPEG)时是否有办法检查DPI - Is there a way when uploading images (JPEG) to check the DPI?

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

本文关键字：检查 DPI 是否图像 JPEG | 更新日期: 2023-09-26

上传图像(JPEG)时是否有办法检查DPI?

我想把它集成到一个表单中，所以作为一个验证器。

您必须使用Imagick(或Gmagick)打开图像，然后调用getImageResolution。

$image = new Imagick($path_to_image);
var_dump($image->getImageResolution());

结果:

Array
(
    [x]=>75
    [y]=>75
)

编辑:

对于symfony的集成，您可以为此使用自定义验证器。您可以扩展默认值来验证文件并添加DPI限制。

创建这个到/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;
  }
}

然后，在表单中，对文件使用以下验证器:

$this->validatorSchema['file'] = new myCustomValidatorFile(array(
  'resolution_dpi' => 300,
  'mime_types'     => 'web_images',
  'path'           => sfConfig::get('sf_upload_dir'),
  'required'       => true
));