lorenzo milesi Posts

Today I had to convert a PDF into a web embeddable image. In the past we used to run Ghostscript via exec()/system() calls, but that’s annoying because you have to deal with temporary files, if you don’t intend to keep them for archive. So I wanted to try a more decent way: convert the PDF using PHP’s Imagick libraries and display the image inline, using data-uri. This is the code I came up with:

try {
    // [0] means pick just the first page of the PDF http://php.net/manual/en/imagick.construct.php#113801
    $img = new \Imagick(Yii::getAlias("@app/documenti/pdf/{$this->telaio}-{$this->id}.pdf[0]"));
} catch (\ImagickException $e) {
    Yii::trace($e->getMessage(), __METHOD__);
    // If there's an error, most likely missing file, display a transparent PNG
    // If you want smaller image you can use GIF, but I had to display it in a mPDF document and it didn't like it 
    return 'data:image/gif;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABAQMAAAAl21bKAAAAA1BMVEUAAACnej3aAAAAAXRSTlMAQObYZgAAAAFiS0dEAIgFHUgAAAAJcEhZcwAACxMAAAsTAQCanBgAAAAHdElNRQfhCw0MIjeCY5EAAAAACklEQVQI12NgAAAAAgAB4iG8MwAAAABJRU5ErkJggg==';
}
$img->setImageFormat("png");
return 'data:image/png;base64,'.base64_encode($img->getimageblob());

Unfortunately the exception I got was not about a missing file (which of course could have been properly checked), but:

ImagickException FailedToExecuteCommand ‘gs’

Ok, given that you have GhostScript installed (maybe via Homebrew), and gs command is in your path, let’s see why it’s not working.