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Merged
broccolingual merged 1 commit into from
Aug 12, 2025
Merged

add: implement a file reader example #8

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4 changes: 4 additions & 0 deletions Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -35,3 +35,7 @@ path = "examples/inputs.rs"
[[example]]
name = "tetris"
path = "examples/tetris/src/main.rs"

[[example]]
name = "file_reader"
path = "examples/file_reader.rs"
10 changes: 9 additions & 1 deletion README.md
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Expand Up @@ -94,6 +94,14 @@ cargo run --example tetris

![](docs/ex_tetris.png)

#### File Reader

```bash
cargo run --example file_reader <file_path>
```

![](docs/ex_file_reader.png)

## Platform Support

Currently supports Unix-like systems:
Expand Down Expand Up @@ -130,4 +138,4 @@ This project is licensed under the MIT License - see the LICENSE file for detail

---

**Note**: This library is designed for educational purposes and as a foundation for terminal-based applications. For production use, consider established libraries like `crossterm` or `ratatui-rs` depending on your needs.
**Note**: This library is designed for educational purposes and as a foundation for terminal-based applications. For production use, consider established libraries like `crossterm` or `ratatui` depending on your needs.
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202 changes: 202 additions & 0 deletions examples/file_reader.rs
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@@ -0,0 +1,202 @@
use rustui::*;
use std::{
fs::File,
io::{self, BufRead, BufReader},
thread, time,
};

const RENDERING_RATE: time::Duration = time::Duration::from_millis(31); // ms
const INPUT_CAPTURING_RATE: time::Duration = time::Duration::from_millis(10); // ms

fn main() -> Result<(), Box<dyn std::error::Error>> {
let args: Vec<String> = std::env::args().collect();
let file_path = if args.len() > 1 {
&args[1]
} else {
eprintln!("Usage: file_reader <file_path>");
return Ok(());
};

let mut file_reader = FileReader::new(file_path);

let mut win = Window::new(false)?;
win.initialize(RENDERING_RATE)?; // Initialize the window and start the rendering thread
let input_rx = InputListener::new(INPUT_CAPTURING_RATE); // Create an input listener

loop {
// Check for key presses
if let Ok(event) = input_rx.try_recv() {
match event {
InputEvent::Key(Key::Char('q')) => break,
InputEvent::Key(Key::ArrowUp) => {
file_reader.scroll_up();
}
InputEvent::Key(Key::ArrowDown) => {
let visible_lines = win.height.saturating_sub(4);
file_reader.scroll_down(visible_lines);
}
InputEvent::Key(Key::PageUp) => {
let visible_lines = win.height.saturating_sub(4);
file_reader.page_up(visible_lines);
}
InputEvent::Key(Key::PageDown) => {
let visible_lines = win.height.saturating_sub(4);
file_reader.page_down(visible_lines);
}
InputEvent::Key(Key::Home) => {
file_reader.current_line = 0;
file_reader.scroll_offset = 0;
}
InputEvent::Key(Key::End) => {
let visible_lines = win.height.saturating_sub(4);
file_reader.current_line = file_reader.lines.len().saturating_sub(1);
file_reader.scroll_offset =
file_reader.lines.len().saturating_sub(visible_lines);
}
_ => {}
}
}

// Draw the frame
win.draw(|canvas| {
file_reader.render(canvas);
})?;

thread::sleep(time::Duration::from_millis(31)); // Sleep to prevent high CPU usage
}
Ok(())
}

struct FileReader {
file_path: String,
lines: Vec<String>,
current_line: usize,
scroll_offset: usize,
}

impl FileReader {
fn new(file_path: &str) -> Self {
let file = File::open(file_path).unwrap();
let reader = BufReader::new(file);
let lines: Result<Vec<String>, io::Error> = reader.lines().collect();
Self {
file_path: file_path.to_string(),
lines: lines.unwrap(),
current_line: 0,
scroll_offset: 0,
}
}

fn scroll_up(&mut self) {
if self.current_line > 0 {
self.current_line -= 1;
if self.current_line < self.scroll_offset {
self.scroll_offset = self.current_line;
}
}
}

fn scroll_down(&mut self, visible_lines: usize) {
if self.current_line + 1 < self.lines.len() {
self.current_line += 1;
if self.current_line >= self.scroll_offset + visible_lines {
self.scroll_offset = self.current_line - visible_lines + 1;
}
}
}

fn page_up(&mut self, visible_lines: usize) {
let page_size = visible_lines.saturating_sub(1);
self.current_line = self.current_line.saturating_sub(page_size);
self.scroll_offset = self.scroll_offset.saturating_sub(page_size);
}

fn page_down(&mut self, visible_lines: usize) {
let page_size = visible_lines.saturating_sub(1);
self.current_line = (self.current_line + page_size).min(self.lines.len().saturating_sub(1));

if self.current_line >= self.scroll_offset + visible_lines {
self.scroll_offset = self.current_line - visible_lines + 1;
}
}

fn render(&self, canvas: &mut Framebuffer) {
// ボーダーを設定（ファイル名を表示）
canvas.set_named_border(
&format!("File Reader - {}", self.file_path),
Align::Center,
Attr::NORMAL,
Color::White,
Color::default(),
);

// コンテンツ表示領域のサイズを計算（ボーダーを除く）
let content_width = canvas.width.saturating_sub(4);
let content_height = canvas.height.saturating_sub(4);
let start_x = 2;
let start_y = 2;

// ファイルの内容を表示
for (i, line_idx) in (self.scroll_offset..self.scroll_offset + content_height).enumerate() {
if line_idx >= self.lines.len() {
break;
}

let line = &self.lines[line_idx];
let is_current = line_idx == self.current_line;

// 現在行のハイライト
let (attrs, fg, bg) = if is_current {
(Attr::NORMAL, Color::Black, Color::White)
} else {
(Attr::NORMAL, Color::White, Color::default())
};

// 行番号を表示
let line_number = format!("{:4} ", line_idx + 1);
canvas.set_str(
start_x,
start_y + i,
&line_number,
attrs,
Color::Cyan,
bg,
Align::Left,
);

// ファイルの内容を表示（長い行は切り詰める）
let display_line = if line.len() > content_width - 5 {
format!("{}...", &line[..content_width - 8])
} else {
line.clone()
};

canvas.set_str(
start_x + 5,
start_y + i,
&display_line,
attrs,
fg,
bg,
Align::Left,
);
}

// ステータスバーを表示
let status = format!(
"Line {}/{} | Press ↑↓ to scroll, PgUp/PgDn for pages, 'q' to quit",
self.current_line + 1,
self.lines.len()
);

canvas.set_str(
canvas.width / 2,
canvas.height - 1,
&status,
Attr::NORMAL,
Color::Yellow,
Color::default(),
Align::Center,
);
}
}