DEVELOPING.md

Developing

Contributions to the module are welcome!

• Issues should be filed at Drupal.org.
• Code changes can be submitted in the patch form and uploaded to the Drupal.org issue or as a GitHub pull request.

Contributing a new image effect

Please note that in order to keep the codebase clean, the code for new image effects in this module need to follow the Drupal coding standards. Only patches that fulfill the PHPCS checks will be committed.

In addition, there are some specific rules for the image effects and the image toolkit operations that need to be obeyed to keep your code reviewable and maintainable in the future.

New effects MUST HAVE:

1. an entry in the README.md table where effects are listed, including applicable toolkits
2. a class name (and file) that follows the [Effect]ImageEffect naming convention
3. an id in the plugin annotation that follows the image_effects_[effect] naming convention
4. an appropriate config schema entry in config/schema/image_effects.schema.yml, even if the effect has no parameters
5. an implementation of ::transformDimensions if the effect changes height/width of the image
6. if the effect has parameters:
   1. an image_effects_[effect]_summary entry in image_effects_theme() in image_effects.module
   2. a Twig template for the effect summary under templates/image-effects-[effect]-summary.html.twig
   3. the effect form using '#type' => 'image_effects_color' form elements to capture color information where needed
   4. the effect form using the image selector plugin to capture an image file URL if necessary
   5. the effect form using the font selector plugin to capture a font file URL if necessary
   6. the effect form using '#type' => 'image_effects_px_perc' form elements to capture information that can be expressed either as an absolute number or as a percentage
7. if image toolkit operation plugins are needed:
   1. a trait with ::arguments and ::validateArguments if image toolkit operations are implemented, so that the toolkit specific code resides only in the ::execute method of the operation
   2. implementations of operations for both GD and ImageMagick toolkits - if a toolkit cannot support the operation, the implementation should be a no-op returning TRUE
8. a PHPUnit functional effect test extending from ImageEffectsTestBase, testing both toolkits, testing changes of size if the effect does so (both for ::applyEffect and ::transformDimensions), and doing pixel level testing of the resulting image if possible