Josh McKinney 6dcd53bc6b
feat: add ergonomic methods for layouting Rects (#1909)
This commit introduces new methods for the `Rect` struct that simplify
the process of splitting a `Rect` into sub-rects according to a given
`Layout`. By putting these methods on the `Rect` struct, we make it a
bit more natural that a layout is applied to the `Rect` itself, rather
than passing a `Rect` to the `Layout` struct to be split.

Adds:
- `Rect::layout` and `Rect::try_layout` methods that allow splitting a
  `Rect` into an array of sub-rects according to a given `Layout`.
- `Rect::layout_vec` method that returns a `Vec` of sub-rects.
- `Layout::try_areas` method that returns an array of sub-rects, with
  compile-time checks for the number of constraints. This is added
  mainly for consistency with the new `Rect` methods.

```rust
use ratatui_core::layout::{Layout, Constraint, Rect};
let area = Rect::new(0, 0, 10, 10);
let layout = Layout::vertical([Constraint::Fill(1); 2]);

// Rect::layout() infers the number of constraints at compile time:
let [top, main] = area.layout(&layout);

// Rect::try_layout() and Layout::try_areas() do the same, but return a
// Result:
let [top, main] = area.try_layout(&layout)?;
let [top, main] = layout.try_areas(area)?;

// Rect::layout_vec() returns a Vec of sub-rects:
let areas_vec = area.layout_vec(&layout);

// you can also explicitly specify the number of constraints:
let areas = area.layout::<2>(&layout);
let areas = area.try_layout::<2>(&layout)?;
let areas = layout.try_areas::<2>(area)?;
```
2025-06-28 01:23:34 -07:00

95 lines
3.2 KiB
Rust

//! # [Ratatui] `Paragraph` example
//!
//! The latest version of this example is available in the [widget examples] folder in the
//! repository.
//!
//! Please note that the examples are designed to be run against the `main` branch of the Github
//! repository. This means that you may not be able to compile with the latest release version on
//! crates.io, or the one that you have installed locally.
//!
//! See the [examples readme] for more information on finding examples that match the version of the
//! library you are using.
//!
//! [Ratatui]: https://github.com/ratatui/ratatui
//! [widget examples]: https://github.com/ratatui/ratatui/blob/main/ratatui-widgets/examples
//! [examples readme]: https://github.com/ratatui/ratatui/blob/main/examples/README.md
use color_eyre::Result;
use crossterm::event;
use ratatui::Frame;
use ratatui::layout::{Alignment, Constraint, Layout, Rect};
use ratatui::style::{Color, Stylize};
use ratatui::text::{Line, Masked, Span};
use ratatui::widgets::{Paragraph, Wrap};
fn main() -> Result<()> {
color_eyre::install()?;
ratatui::run(|terminal| {
loop {
terminal.draw(render)?;
if event::read()?.is_key_press() {
break Ok(());
}
}
})
}
/// Render the UI with various text.
fn render(frame: &mut Frame) {
let vertical = Layout::vertical([Constraint::Length(1), Constraint::Fill(1)]).spacing(1);
let horizontal = Layout::horizontal([Constraint::Percentage(50); 2]).spacing(1);
let [top, main] = frame.area().layout(&vertical);
let [first, second] = main.layout(&horizontal);
let title = Line::from_iter([
Span::from("Paragraph Widget").bold(),
Span::from(" (Press 'q' to quit)"),
]);
frame.render_widget(title.centered(), top);
render_centered_paragraph(frame, first);
render_wrapped_paragraph(frame, second);
}
/// Render a paragraph with centered text.
pub fn render_centered_paragraph(frame: &mut Frame, area: Rect) {
let text = "Centered text\nwith multiple lines.\nCheck out the recipe!";
let paragraph = Paragraph::new(text)
.style(Color::White)
.alignment(Alignment::Center);
frame.render_widget(paragraph, area);
}
/// Render a long paragraph that wraps text.
pub fn render_wrapped_paragraph(frame: &mut Frame, area: Rect) {
let paragraph = Paragraph::new(create_lines(area))
.style(Color::White)
.scroll((0, 0))
.wrap(Wrap { trim: true });
frame.render_widget(paragraph, area);
}
/// Returns the lines for the paragraph.
fn create_lines(area: Rect) -> Vec<Line<'static>> {
let short_line = "Slice, layer, and bake the vegetables. ";
let long_line = short_line.repeat((area.width as usize) / short_line.len() + 2);
vec![
"Recipe: Ratatouille".into(),
"Ingredients:".bold().into(),
Line::from_iter([
"Bell Peppers".into(),
", Eggplant".italic(),
", Tomatoes".bold(),
", Onion".into(),
]),
Line::from_iter([
"Secret Ingredient: ".underlined(),
Span::styled(Masked::new("herbs de Provence", '*'), Color::Red),
]),
"Instructions:".bold().yellow().into(),
long_line.green().italic().into(),
]
}