ratatui/examples/barchart.rs
Florian Dehau 6cb57f5d2a feat: add stateful widgets
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.
2020-02-23 19:23:37 +01:00

128 lines
3.8 KiB
Rust

#[allow(dead_code)]
mod util;
use std::io;
use termion::event::Key;
use termion::input::MouseTerminal;
use termion::raw::IntoRawMode;
use termion::screen::AlternateScreen;
use tui::backend::TermionBackend;
use tui::layout::{Constraint, Direction, Layout};
use tui::style::{Color, Modifier, Style};
use tui::widgets::{BarChart, Block, Borders};
use tui::Terminal;
use crate::util::event::{Event, Events};
struct App<'a> {
data: Vec<(&'a str, u64)>,
}
impl<'a> App<'a> {
fn new() -> App<'a> {
App {
data: vec![
("B1", 9),
("B2", 12),
("B3", 5),
("B4", 8),
("B5", 2),
("B6", 4),
("B7", 5),
("B8", 9),
("B9", 14),
("B10", 15),
("B11", 1),
("B12", 0),
("B13", 4),
("B14", 6),
("B15", 4),
("B16", 6),
("B17", 4),
("B18", 7),
("B19", 13),
("B20", 8),
("B21", 11),
("B22", 9),
("B23", 3),
("B24", 5),
],
}
}
fn update(&mut self) {
let value = self.data.pop().unwrap();
self.data.insert(0, value);
}
}
fn main() -> Result<(), failure::Error> {
// Terminal initialization
let stdout = io::stdout().into_raw_mode()?;
let stdout = MouseTerminal::from(stdout);
let stdout = AlternateScreen::from(stdout);
let backend = TermionBackend::new(stdout);
let mut terminal = Terminal::new(backend)?;
terminal.hide_cursor()?;
// Setup event handlers
let events = Events::new();
// App
let mut app = App::new();
loop {
terminal.draw(|mut f| {
let chunks = Layout::default()
.direction(Direction::Vertical)
.margin(2)
.constraints([Constraint::Percentage(50), Constraint::Percentage(50)].as_ref())
.split(f.size());
let barchart = BarChart::default()
.block(Block::default().title("Data1").borders(Borders::ALL))
.data(&app.data)
.bar_width(9)
.style(Style::default().fg(Color::Yellow))
.value_style(Style::default().fg(Color::Black).bg(Color::Yellow));
f.render_widget(barchart, chunks[0]);
let chunks = Layout::default()
.direction(Direction::Horizontal)
.constraints([Constraint::Percentage(50), Constraint::Percentage(50)].as_ref())
.split(chunks[1]);
let barchart = BarChart::default()
.block(Block::default().title("Data2").borders(Borders::ALL))
.data(&app.data)
.bar_width(5)
.bar_gap(3)
.style(Style::default().fg(Color::Green))
.value_style(Style::default().bg(Color::Green).modifier(Modifier::BOLD));
f.render_widget(barchart, chunks[0]);
let barchart = BarChart::default()
.block(Block::default().title("Data3").borders(Borders::ALL))
.data(&app.data)
.style(Style::default().fg(Color::Red))
.bar_width(7)
.bar_gap(0)
.value_style(Style::default().bg(Color::Red))
.label_style(Style::default().fg(Color::Cyan).modifier(Modifier::ITALIC));
f.render_widget(barchart, chunks[1]);
})?;
match events.next()? {
Event::Input(input) => {
if input == Key::Char('q') {
break;
}
}
Event::Tick => {
app.update();
}
}
}
Ok(())
}