PDF Cover

Automatically generates a cover image (WebP or JPEG) from the first page of a PDF file attached to a Total CMS object. The cover is served at a stable public URL so you can use it as a visual pointer to the magazine or publication.

How it works

When an object is saved and it has a file (or depot) property containing a PDF, the extension automatically:

1. Reads the raw PDF from the data store.
2. Renders page 1 as a scaled image using the bundled pdftoppm (from Poppler).
3. Converts it to WebP using PHP's GD library (JPEG fallback if webp is unavailable).
4. Stores the result in extension-private storage.
5. Serves it from {{ site.url }}/ext/tcms3/pdf-cover/cover/{collection}/{objectId}.webp

If the PDF filename on a saved object does not change from the previous save, the cover is not regenerated — nothing wasted on each save. Changing the PDF triggers a fresh cover on the next save.

Using it in a Twig template

{% set object = fetch_object('vox', 'issue-42') %}
<img src="{{ object|pdf_cover('vox') }}" alt="Cover of issue 42">

Or use the direct public route:

<img src="{{ site.url }}/ext/tcms3/pdf-cover/cover/vox/issue-42.webp" alt="Cover">

The route falls back to JPEG if no webp version is available for that object.

Where the generated image lives

The covers are stored in TCMS extension-private storage under:

tcms-data/.system/extension-data/tcms3/pdf-cover/covers/

They are derived artefacts — not editable through the admin. They regenerate automatically when the source PDF changes.

Poppler / pdftoppm

The extension bundles a minimal Poppler distribution at vendor/poppler/, which provides the pdftoppm command it needs to rasterise the PDF. The generator searches the bundled binary first, then falls back to any system-installed pdftoppm (/opt/homebrew/bin/, /usr/local/bin/, /usr/bin/).

To manually verify:

[site url]/tcms-data/extensions/tcms3/pdf-cover/vendor/poppler/pdftoppm -v

Requirements

• PHP 8.2 with GD.
• PHP must be able to call exec() (no disable_functions restriction).