The Widget trait consumes self, which makes it impossible to use in a
boxed context. Previously we implemented the Widget trait for &T, but
this was not enough to render a boxed widget. We now have a new trait
called `WidgetRef` that allows rendering a widget by reference. This
trait is useful when you want to store a reference to one or more
widgets and render them later. Additionaly this makes it possible to
render boxed widgets where the type is not known at compile time (e.g.
in a composite layout with multiple panes of different types).
This change also adds a new trait called `StatefulWidgetRef` which is
the stateful equivalent of `WidgetRef`.
Both new traits are gated behind the `unstable-widget-ref` feature flag
as we may change the exact name / approach a little on this based on
further discussion.
Blanket implementation of `Widget` for `&W` where `W` implements
`WidgetRef` and `StatefulWidget` for `&W` where `W` implements
`StatefulWidgetRef` is provided. This allows you to render a widget by
reference and a stateful widget by reference.
A blanket implementation of `WidgetRef` for `Option<W>` where `W`
implements `WidgetRef` is provided. This makes it easier to render
child widgets that are optional without the boilerplate of unwrapping
the option. Previously several widgets implemented this manually. This
commits expands the pattern to apply to all widgets.
```rust
struct Parent {
child: Option<Child>,
}
impl WidgetRef for Parent {
fn render_ref(&self, area: Rect, buf: &mut Buffer) {
self.child.render_ref(area, buf);
}
}
```
```rust
let widgets: Vec<Box<dyn WidgetRef>> = vec![Box::new(Greeting), Box::new(Farewell)];
for widget in widgets {
widget.render_ref(buf.area, &mut buf);
}
assert_eq!(buf, Buffer::with_lines(["Hello Goodbye"]));
```
Here's a constraint explorer demo put together with @joshka
https://github.com/ratatui-org/ratatui/assets/1813121/08d7d8f6-d013-44b4-8331-f4eee3589cce
It allows users to interactive explore how the constraints behave with
respect to each other and compare that across flex modes. It allows
users to swap constraints out for other constraints, increment or
decrement the values, add and remove constraints, and add spacing
It is also a good example for how to structure a simple TUI with several
Ratatui code patterns that are useful for refactoring.
Fixes: https://github.com/ratatui-org/ratatui/issues/792
---------
Co-authored-by: Josh McKinney <joshka@users.noreply.github.com>
Updates the requirements on [termwiz](https://github.com/wez/wezterm) to
permit the latest version.
<details>
<summary>Commits</summary>
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href="https://github.com/wez/wezterm/commits">compare view</a></li>
</ul>
</details>
<br />
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This PR makes a number of simplifications to the layout and constraint
features that were added after v0.25.0.
For users upgrading from v0.25.0, the net effect of this PR (along with
the other PRs) is the following:
- New `Flex` modes have been added.
- `Flex::Start` (new default)
- `Flex::Center`
- `Flex::End`
- `Flex::SpaceAround`
- `Flex::SpaceBetween`
- `Flex::Legacy` (old default)
- `Min(v)` grows to allocate excess space in all `Flex` modes instead of
shrinking (except in `Flex::Legacy` where it retains old behavior).
- `Fill(1)` grows to allocate excess space, growing equally with
`Min(v)`.
---
The following contains a summary of the changes in this PR and the
motivation behind them.
**`Flex`**
- Removes `Flex::Stretch`
- Renames `Flex::StretchLast` to `Flex::Legacy`
**`Constraint`**
- Removes `Fixed`
- Makes `Min(v)` grow as much as possible everywhere (except
`Flex::Legacy` where it retains the old behavior)
- Makes `Min(v)` grow equally as `Fill(1)` while respecting `Min` lower
bounds. When `Fill` and `Min` are used together, they both fill excess
space equally.
Allowing `Min(v)` to grow still allows users to build the same layouts
as before with `Flex::Start` with no breaking changes to the behavior.
This PR also removes the unstable feature `SegmentSize`.
This is a breaking change to the behavior of constraints. If users want
old behavior, they can use `Flex::Legacy`.
```rust
Layout::vertical([Length(25), Length(25)]).flex(Flex::Legacy)
```
Users that have constraint that exceed the available space will probably
not see any difference or see an improvement in their layouts. Any
layout with `Min` will be identical in `Flex::Start` and `Flex::Legacy`
so any layout with `Min` will not be breaking.
Previously, `Table` used `EvenDistribution` internally by default, but
with that gone the default is now `Flex::Start`. This changes the
behavior of `Table` (for the better in most cases). The only way for
users to get exactly the same as the old behavior is to change their
constraints. I imagine most users will be happier out of the box with
the new Table default.
Resolves https://github.com/ratatui-org/ratatui/issues/843
Thanks to @joshka for the direction
This commit adds `scroll` to the flex example. It also adds more examples to showcase how constraints interact. It improves the UI to make it easier to understand and short terminal friendly.
<img width="380" alt="image" src="https://github.com/ratatui-org/ratatui/assets/1813121/30541efc-ecbe-4e28-b4ef-4d5f1dc63fec"/>
---------
Co-authored-by: Dheepak Krishnamurthy <me@kdheepak.com>
```shell
cargo run --example demo2 --features="crossterm widget-calendar"
```
Press `d` to activate destroy mode and Enjoy!
Vendors a copy of tui-big-text to allow us to use it in the demo.
This PR adds a new way to space elements in a `Layout`.
Loosely based on
[flexbox](https://css-tricks.com/snippets/css/a-guide-to-flexbox/), this
PR adds a `Flex` enum with the following variants:
- Start
- Center
- End
- SpaceAround
- SpaceBetween
<img width="380" alt="image" src="https://github.com/ratatui-org/ratatui/assets/1813121/b744518c-eae7-4e35-bbc4-fe3c95193cde">
It also adds two more variants, to make this backward compatible and to
make it replace `SegmentSize`:
- StretchLast (default in the `Flex` enum, also behavior matches old
default `SegmentSize::LastTakesRemainder`)
- Stretch (behavior matches `SegmentSize::EvenDistribution`)
The `Start` variant from above matches `SegmentSize::None`.
This allows `Flex` to be a complete replacement for `SegmentSize`, hence
this PR also deprecates the `segment_size` constructor on `Layout`.
`SegmentSize` is still used in `Table` but under the hood `segment_size`
maps to `Flex` with all tests passing unchanged.
I also put together a simple example for `Flex` layouts so that I could
test it visually, shared below:
https://github.com/ratatui-org/ratatui/assets/1813121/c8716c59-493f-4631-add5-feecf4bd4e06
TableState, ListState, and ScrollbarState can now be serialized and deserialized
using serde.
```rust
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
struct AppState {
list_state: ListState,
table_state: TableState,
scrollbar_state: ScrollbarState,
}
let app_state = AppState::default();
let serialized = serde_json::to_string(app_state);
let app_state = serde_json::from_str(serialized);
```
* feat(layout): add a Rect::clamp() method
This ensures a rectangle does not end up outside an area. This is useful
when you want to be able to dynamically move a rectangle around, but
keep it constrained to a certain area.
For example, this can be used to implement a draggable window that can
be moved around, but not outside the terminal window.
```rust
let window_area = Rect::new(state.x, state.y, 20, 20).clamp(area);
state.x = rect.x;
state.y = rect.y;
```
* refactor: use rstest to simplify clamp test
* fix: use rstest description instead of string
test layout::rect::tests:🗜️:case_01_inside ... ok
test layout::rect::tests:🗜️:case_02_up_left ... ok
test layout::rect::tests:🗜️:case_04_up_right ... ok
test layout::rect::tests:🗜️:case_05_left ... ok
test layout::rect::tests:🗜️:case_03_up ... ok
test layout::rect::tests:🗜️:case_06_right ... ok
test layout::rect::tests:🗜️:case_07_down_left ... ok
test layout::rect::tests:🗜️:case_08_down ... ok
test layout::rect::tests:🗜️:case_09_down_right ... ok
test layout::rect::tests:🗜️:case_10_too_wide ... ok
test layout::rect::tests:🗜️:case_11_too_tall ... ok
test layout::rect::tests:🗜️:case_12_too_large ... ok
* fix: less ambiguous docs for this / other rect
* fix: move rstest to dev deps
