Josh McKinney 815757fcbb
feat(widgets): implement Widget for Widget refs (#833)
Many widgets can be rendered without changing their state.

This commit implements The `Widget` trait for references to
widgets and changes their implementations to be immutable.

This allows us to render widgets without consuming them by passing a ref
to the widget when calling `Frame::render_widget()`.

```rust
// this might be stored in a struct
let paragraph = Paragraph::new("Hello world!");

let [left, right] = area.split(&Layout::horizontal([20, 20]));
frame.render_widget(&paragraph, left);
frame.render_widget(&paragraph, right); // we can reuse the widget
```

Implemented for all widgets except BarChart (which has an implementation
that modifies the internal state and requires a rewrite to fix.

Other widgets will be implemented in follow up commits.

Fixes: https://github.com/ratatui-org/ratatui/discussions/164
Replaces PRs: https://github.com/ratatui-org/ratatui/pull/122 and
https://github.com/ratatui-org/ratatui/pull/16
Enables: https://github.com/ratatui-org/ratatui/issues/132
Validated as a viable working solution by:
https://github.com/ratatui-org/ratatui/pull/836
2024-01-24 10:34:10 -08:00
..
2024-01-08 03:51:53 -05:00