January 15, 2024

Image Blur Plugin

Generates base64 encoded, downscaled and blurred versions of media library's images, which can be used f.e. as a placeholder.

Generates base64 encoded, downscaled and blurred versions of media library’s images, which can be used f.e. as a placeholder.

Inspiration

After Wolt showcased their Blurhash technique, I wanted to make something similar to WordPress. Instead of encoding images to base83 like the food delivery company does, I went with base64 so development experience was easier.

How to start using the plugin

Install and activate this plugin in your environment
- The plugin should generate blurs for each image on the activation.
Check an image’s details in your media library. It should have listing of all generated blurs.
To get a blur to a template, use get_post_meta(). Check example theme in plugin’s repository

Customization

The plugin provides few filters, so developers can modify generated blur images to their needs. By default, generated images are 8 pixels wide and passed once through gaussian blur function, which will result in roughly 250-1000 characters long string. To change these, use following hooks:

function modify_image_blur_width( int $width ): int { return 15; } add_filter("image-blur-modify-width", "modify_image_blur_width"); function modify_gaussian_blur_strength( int $strength ): int { return 10; } add_filter("image-blur-modify-gaussian-blur-strength", "modify_gaussian_blur_strength");

FAQ

How to generate blurs for new image sizes?

To regenerate blurs you can:
– use f.e. Regenerate Thumbnails plugin
– use WP CLI if your environment has it installed.
– reactive this plugin (not recommended on high traffic sites)

How do I clear DB from blur data?

This plugin cleans up generated blurs when it is deactivated.

For manual deletion, you can remove all rows from wp_postmeta table that have image_blur_ prefix in meta_key column.

Which image formats are supported?

During development phase, this plugin was tested with .jpg, .jpeg, .gif, .png and .webp, which are the default accepted image types to media library.

Changelog

1.0.0 (2021-11-30):

Initial release

1.0.1 (2021-11-30):

Remove development related files from plugin directory

1.1.0 (2021-12-02):

Add CDN support

1.2.0 (2022-01-10):

Add example script to support WPGraphQL plugin

1.2.1 (2022-01-28):

Update tested up to version to 5.9

1.2.2 (2022-02-28):

Fix the issue when the plugin is accidentally included to environment through mu-plugins and plugins.

2.0.0 (2023-01-26):

Test and confirm that plugin works with PHP 8.0 and WP 6.1.1. Update requires to meet these versions.

2.0.1 (2023-07-26):

Test and confirm that plugin works with PHP 8.1 and WP 6.3.

3.0.0 (2024-01-15):

Rewrite core to be more simpler.
Test and confirm that plugin works with PHP 8.2 and WP 6.4.2.
Test and confirm that plugin work with WP GraphQL plugin 1.19.0.

3.0.1 (2024-01-15):

Remove redundant some files and folders from production package.