Black backgrounds in PDF thumbnails

[rdiazg]

When an user upload some pdfs which contain alpha layers to the media library, the thumbnail preview appears with a unwanted black background. Imagemagick's functions "class-wp-image-editor-imagick.php" not support hooks or filters to fix this behaviour. For testing purposes I was trying fix this with some code like:

<?php
            if ( 'pdf' == $file_extension ) {
                $this->image->setImageAlphaChannel(Imagick::ALPHACHANNEL_REMOVE);
                $this->image->mergeImageLayers(Imagick::LAYERMETHOD_FLATTEN);
            }

in

​https://github.com/WordPress/WordPress/blob/master/wp-includes/class-wp-image-editor-imagick.php#L156

And it's works for me but I don't know how this change affect to the others wordpress features that call this method. Could someone have a look at this?

Thanks in advance.

[swissspidy]

Hi there and welcome to Trac!

It looks like we are already tracking this in #45982. Let's discuss possible solutions there.

[rdiazg]

Sure, thanks for your quick reply :)