This change simplifys UI code that uses the Frame type. E.g.:
```rust
fn draw<B: Backend>(frame: &mut Frame<B>) {
// ...
}
```
Frame was generic over Backend because it stored a reference to the
terminal in the field. Instead it now directly stores the viewport area
and current buffer. These are provided at creation time and are valid
for the duration of the frame.
BREAKING CHANGE: Frame is no longer generic over Backend. Code that
accepted `Frame<Backend>` will now need to accept `Frame`. To migrate
existing code, remove any generic parameters from code that uses an
instance of a Frame. E.g. the above code becomes:
```rust
fn draw(frame: &mut Frame) {
// ...
}
```
This helps to keep the prelude small and less likely to conflict with
other crates.
- remove widgets module from prelude as the entire module can be just as
easily imported with `use ratatui::widgets::*;`
- move prelude module into its own file
- update examples to import widgets module instead of just prelude
- added several modules to prelude to make it possible to qualify
imports that collide with other types that have similar names
- Remove deny warnings in lib.rs. This allows easier iteration when developing
new features. The warnings will make the CI fails anyway on the clippy CI
stage.
- Run clippy on all targets (including tests and examples) and all features.
- Fail CI on clippy warnings.
Most widgets can be drawn directly based on the input parameters. However, some
features may require some kind of associated state to be implemented.
For example, the `List` widget can highlight the item currently selected. This
can be translated in an offset, which is the number of elements to skip in
order to have the selected item within the viewport currently allocated to this
widget. The widget can therefore only provide the following behavior: whenever
the selected item is out of the viewport scroll to a predefined position (make
the selected item the last viewable item or the one in the middle).
Nonetheless, if the widget has access to the last computed offset then it can
implement a natural scrolling experience where the last offset is reused until
the selected item is out of the viewport.
To allow such behavior within the widgets, this commit introduces the following
changes:
- Add a `StatefulWidget` trait with an associated `State` type. Widgets that
can take advantage of having a "memory" between two draw calls needs to
implement this trait.
- Add a `render_stateful_widget` method on `Frame` where the associated
state is given as a parameter.
The chosen approach is thus to let the developers manage their widgets' states
themselves as they are already responsible for the lifecycle of the wigets
(given that the crate exposes an immediate mode api).
The following changes were also introduced:
- `Widget::render` has been deleted. Developers should use `Frame::render_widget`
instead.
- `Widget::background` has been deleted. Developers should use `Buffer::set_background`
instead.
- `SelectableList` has been deleted. Developers can directly use `List` where
`SelectableList` features have been back-ported.
It basically never makes sense to render without syncing the size.
Without resizing, if shrinking, we get artefacts. If growing, we may get
panics (before this change the Rustbox sample (the only one which didn't
handle resizing on its own) panicked because the widget would get an
updated size, while the terminal would not).
