variant

Returns an ActiveStorage::Variant instance with the set of transformations provided. This is only relevant for image files, and it allows any image to be transformed for size, colors, and the like. Example:

avatar.variant(resize_to_limit: [100, 100]).processed.url

This will create and process a variant of the avatar blob that’s constrained to a height and width of 100px. Then it’ll upload said variant to the service according to a derivative key of the blob and the transformations.

Frequently, though, you don’t actually want to transform the variant right away. But rather simply refer to a specific variant that can be created by a controller on-demand. Like so:

<%= image_tag Current.user.avatar.variant(resize_to_limit: [100, 100]) %>

This will create a URL for that specific blob with that specific variant, which the ActiveStorage::RepresentationsController can then produce on-demand.

Raises ActiveStorage::InvariableError if ImageMagick cannot transform the blob. To determine whether a blob is variable, call ActiveStorage::Blob#variable?.