• I read the Generative AI policy and my contribution is either not created with the help of AI or is compatible with the policy and GNU/GPL 2 or later.

Summary of Changes

This issue was discovered in the Media Manager when the Create Thumbnails option is enabled in the Filesystem - Local plugin, and the folder contains an image with an extreme aspect ratio, e.g. 1000×2, 1920×4 or 2×1000.

LocalAdapter::createThumbnail() calls Image::createThumbnails() with SCALE_INSIDE, which goes through Image::resize() and Image::prepareDimensions().

When the shorter side is divided by the scale ratio in Image::prepareDimensions() and the result is below 0.5, it rounds to 0. That 0 is passed to imagecreatetruecolor(), which throws a ValueError and stops the Media Manager listing when thumbnails are enabled.

The same applies to any Image::resize() call using SCALE_INSIDE, SCALE_OUTSIDE or SCALE_FIT.

This change ensures that the width and height calculated by prepareDimensions() are at least 1px.

Testing Instructions

Enable Create Thumbnails in Filesystem - Local, upload a 1000×2 image (or 2×1000), and open that folder in the Media Manager.

Actual result BEFORE applying this Pull Request

The ValueError is thrown and the folder doesn't list, e.g.

imagecreatetruecolor(): Argument #2 ($height) must be greater than 0

Expected result AFTER applying this Pull Request

The folder lists and a thumbnail of 200×1 is generated for the image.

Link to documentations

Please select:

• Documentation link for guide.joomla.org:

• No documentation changes for guide.joomla.org needed

• Pull Request link for manual.joomla.org:

• No documentation changes for manual.joomla.org needed