71 lines
2.7 KiB
Markdown
71 lines
2.7 KiB
Markdown
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# `unicode-width`
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[](https://github.com/unicode-rs/unicode-width/actions/workflows/rust.yml)
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[](https://crates.io/crates/unicode-width)
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[](https://docs.rs/unicode-width/)
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Determine displayed width of `char` and `str` types according to [Unicode Standard Annex #11][UAX11]
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and other portions of the Unicode standard.
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This crate is `#![no_std]`.
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[UAX11]: http://www.unicode.org/reports/tr11/
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```rust
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use unicode_width::UnicodeWidthStr;
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fn main() {
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let teststr = "Ｈｅｌｌｏ, ｗｏｒｌｄ!";
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let width = teststr.width();
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println!("{}", teststr);
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println!("The above string is {} columns wide.", width);
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let width = teststr.width_cjk();
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println!("The above string is {} columns wide (CJK).", width);
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}
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```
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**NOTE:** The computed width values may not match the actual rendered column
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width. For example, many Brahmic scripts like Devanagari have complex rendering rules
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which this crate does not currently handle (and will never fully handle, because
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the exact rendering depends on the font):
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```rust
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extern crate unicode_width;
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use unicode_width::UnicodeWidthStr;
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fn main() {
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assert_eq!("क".width(), 1); // Devanagari letter Ka
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assert_eq!("ष".width(), 1); // Devanagari letter Ssa
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assert_eq!("क्ष".width(), 2); // Ka + Virama + Ssa
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}
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```
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Additionally, [defective combining character sequences](https://unicode.org/glossary/#defective_combining_character_sequence)
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and nonstandard [Korean jamo](https://unicode.org/glossary/#jamo) sequences may
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be rendered with a different width than what this crate says. (This is not an
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exhaustive list.) For a list of what this crate *does* handle, see
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[docs.rs](https://docs.rs/unicode-width/latest/unicode_width/#rules-for-determining-width).
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## crates.io
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You can use this package in your project by adding the following
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to your `Cargo.toml`:
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```toml
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[dependencies]
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unicode-width = "0.2"
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```
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## Changelog
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### 0.2.0
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- Treat `\n` as width 1 (#60)
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- Treat ambiguous `Modifier_Letter`s as narrow (#63)
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- Support `Grapheme_Cluster_Break=Prepend` (#62)
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- Support lots of ligatures (#53)
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Note: If you are using `unicode-width` for linebreaking, the change treating `\n` as width 1 _may cause behavior changes_. It is recommended that in such cases you feed already-line segmented text to `unicode-width`. In other words, please apply higher level control character based line breaking protocols before feeding text to `unicode-width`. Relying on any character producing a stable width in this crate is likely the sign of a bug.
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