unicode-width-utils 0.1.4

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[crate]: https://crates.io/crates/unicode-width-utils
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[docs]: https://docs.rs/unicode-width-utils/

# unicode-width-utils

A thin-wrapper for the [`unicode-width` crate] with additional functionalities,
such as dynamic configuration for CJK (East Asian Ambiguous) widths and
safe string truncation.

## Features

- **Dynamic CJK Config**: Treat East Asian Ambiguous characters (such as Greek,
  Cyrillic, and CJK characters) as either 1 or 2 columns wide.
- **Environment Variable Override**: Initialize the default CJK mode using
  `UNICODE_WIDTH=cjk`.
- **Thread-safe Global Default**: Change the global CJK default at runtime.
- **Safe Truncation**: Truncate strings to a specific column width
  without breaking UTF-8 characters,
  including optional tab support.

## Installation
```bash
cargo add unicode-width-utils
```

## Usage

### Basic Example

```rust
use unicode_width_utils::UnicodeWidth;

fn main() {
    let uw = UnicodeWidth::new();
    assert_eq!(uw.char('A'), Some(1));
    assert_eq!(uw.str("Hello"), 5);
}
```

### CJK Ambiguous Widths

You can explicitly configure whether East Asian Ambiguous characters are treated
as 1 or 2 columns wide:
```rust
use unicode_width_utils::UnicodeWidth;

fn main() {
    // Treat ambiguous characters as 1 column wide
    let non_cjk = UnicodeWidth::with_cjk(false);
    assert_eq!(non_cjk.char('█'), Some(1));

    // Treat ambiguous characters as 2 columns wide (CJK mode)
    let cjk = UnicodeWidth::with_cjk(true);
    assert_eq!(cjk.char('█'), Some(2));
}
```

### Global Default Configuration

You can change the default configuration
for future instances created via `UnicodeWidth::new()`:
```rust
use unicode_width_utils::UnicodeWidth;

fn main() {
    // Globally set the default mode to CJK
    UnicodeWidth::set_default_cjk(true);
    
    let uw = UnicodeWidth::new();
    assert_eq!(uw.char('█'), Some(2));
}
```

Alternatively, you can initialize the default CJK mode
via the environment variable:
```bash
UNICODE_WIDTH=cjk
```

### String Truncation

Truncate a string slice so that its total display width does not exceed a maximum limit:

```rust
use unicode_width_utils::UnicodeWidth;

fn main() {
    let uw = UnicodeWidth::with_cjk(false);
    assert_eq!(uw.truncate("hello", 3), "hel");

    let cjk = UnicodeWidth::with_cjk(true);
    // 'あ' is 2 columns wide
    assert_eq!(cjk.truncate("あああ", 3), "あ");
    assert_eq!(cjk.truncate("A█B", 2), "A");
}
```

## License

Licensed under the Apache License, Version 2.0.

[`unicode-width` crate]: https://crates.io/crates/unicode-width