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

88 lines
2.9 KiB
Rust

//! # [Ratatui] `Canvas` 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::{Constraint, Layout, Rect};
use ratatui::style::{Color, Stylize};
use ratatui::symbols::Marker;
use ratatui::text::{Line as TextLine, Span};
use ratatui::widgets::canvas::{Canvas, Line, Map, MapResolution, Rectangle};
use ratatui_widgets::canvas::Points;
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 a canvas widget.
fn render(frame: &mut Frame) {
let vertical = Layout::vertical([Constraint::Length(1), Constraint::Fill(1)]).spacing(1);
let horizontal = Layout::horizontal([Constraint::Percentage(100)]).spacing(1);
let [top, main] = frame.area().layout(&vertical);
let [area] = main.layout(&horizontal);
let title = TextLine::from_iter([
Span::from("Canvas Widget").bold(),
Span::from(" (Press 'q' to quit)"),
]);
frame.render_widget(title.centered(), top);
render_canvas(frame, area);
}
/// Renders the canvas widget with various shapes and a map.
pub fn render_canvas(frame: &mut Frame, area: Rect) {
let canvas = Canvas::default()
.x_bounds([-180.0, 180.0])
.y_bounds([-90.0, 90.0])
.marker(Marker::Braille)
.paint(|ctx| {
ctx.draw(&Map {
resolution: MapResolution::High,
color: Color::White,
});
ctx.layer();
ctx.draw(&Line::new(0.0, 10.0, 10.0, 10.0, Color::Blue));
ctx.draw(&Rectangle {
x: 10.0,
y: 20.0,
width: 10.0,
height: 10.0,
color: Color::Green,
});
ctx.draw(&Points {
coords: &[
(2.3522, 48.8566), // Paris
(-122.3321, 47.6062), // Seattle
(-79.3837, 43.6511), // Toronto
(32.8597, 39.9334), // Ankara
],
color: Color::Red,
});
});
frame.render_widget(canvas, area);
}