Ben Konyi 610c06fae6

[ Widget Preview ] Allow for custom Preview annotations, add support for runtime transformations (#175535) ...

This change updates `Preview` to be a `base` class instead of `final`,
allowing for developers to extend `Preview` and create their own custom
preview annotations.

To reduce friction associated with working with `const` constructors,
two new methods have been added: `MultiPreview.transform()` and
`Preview.transform()`. These methods are invoked at runtime by the
preview environment, allowing for developers to create or modify
`Preview` instances with non-constant values. This also relaxes
restrictions around `Preview`'s callback parameters (e.g., `wrapper`),
which do not need to be static or public when provided to a `Preview` in
the context of a `*.transform()` method. This makes it possible to
create custom preview classes that completely encapsulate their
callbacks, removing the need for separate public, static function
declarations.

To make transforming `Preview`s simpler, a `PreviewBuilder` utility
class has also been added.

Fixes https://github.com/flutter/flutter/issues/175534

2025-09-22 20:10:48 +00:00

..

widget_previews.dart

[ Widget Preview ] Allow for custom Preview annotations, add support for runtime transformations (#175535)

2025-09-22 20:10:48 +00:00