[−][src]Crate harfbuzz_rs

harfbuzz_rs is a high-level interface to HarfBuzz, exposing its most important functionality in a safe manner using Rust.

What is HarfBuzz?

HarfBuzz is a library for performing complex text layout. It does not perform any drawing. This is quite a low-level operation. If you want to simply draw some text on the screen choose another library. However if you want to build a library for drawing text on some canvas or need a lot of control on advanced text layout then this is the right library to use.

Getting Started

To shape a simple string of text you just create a Font from a font file, fill a Buffer with some text and call the shape function.

use harfbuzz_rs::*;


let path = "path/to/some/font_file.otf";
let index = 0; //< face index in the font file
let face = Face::from_file(path, index)?;
let mut font = Font::new(face);

let buffer = UnicodeBuffer::new().add_str("Hello World!");
let output = shape(&font, buffer, &[]);

// The results of the shaping operation are stored in the `output` buffer.

let positions = output.get_glyph_positions();
let infos = output.get_glyph_infos();

assert_eq!(positions.len(), infos.len());

// iterate over the shaped glyphs
for (position, info) in positions.iter().zip(infos) {
    let gid = info.codepoint;
    let cluster = info.cluster;
    let x_advance = position.x_advance;
    let x_offset = position.x_offset;
    let y_offset = position.y_offset;

    // Here you would usually draw the glyphs.
    println!("gid{:?}={:?}@{:?},{:?}+{:?}", gid, cluster, x_advance, x_offset, y_offset);
}

This should print out something similar to the following:

gid41=0@741,0+0
gid70=1@421,0+0
gid77=2@258,0+0
gid77=3@253,0+0
gid80=4@510,0+0
gid1=5@227,0+0
gid56=6@874,0+0
gid80=7@498,0+0
gid83=8@367,0+0
gid77=9@253,0+0
gid69=10@528,0+0
gid2=11@276,0+0

Re-exports

pub use harfbuzz_sys as hb;

pub use crate::font_funcs::FontFuncs;

Modules

font_funcs

Contains the FontFuncs trait.

Structs

Blob	A `Blob` manages raw data like e.g. file contents. It refers to a slice of bytes that can be either owned by the `Blob` or not.
BufferSerializer	A type that can be used to serialize a `GlyphBuffer`.
Codepoints	An iterator over the codepoints stored in a `UnicodeBuffer`.
Face	A wrapper around `hb_face_t`.
Feature	A feature tag with an accompanying range specifying on which subslice of `shape`s input it should be applied.
Font	A type representing a single font (i.e. a specific combination of typeface and typesize).
FontExtents
GlyphBuffer	A `GlyphBuffer` contains the resulting output information of the shaping process.
GlyphFlags	A set of flags that may be set during shaping on each glyph.
GlyphInfo
GlyphPosition	`GlyphPosition` is the structure that holds the positions of the glyph in both horizontal and vertical directions. All positions in `GlyphPosition` are relative to the current point.
InvalidLanguage
Language
Owned	A smart pointer that wraps a singly owned harfbuzz object.
Script
SegmentProperties
SerializeFlags	Flags used for serialization with a `BufferSerializer`.
Shared	A smart pointer that wraps an atomically reference counted HarfBuzz object.
Tag	A type to represent 4-byte SFNT tags.
UnicodeBuffer	A `UnicodeBuffer` can be filled with unicode text and corresponding cluster indices.

Enums

Direction	Defines the direction in which text is to be read.
SerializeFormat	The serialization format used in `BufferSerializer`.
TagFromStrErr	An Error generated when a `Tag` fails to parse from a `&str` with the `from_str` function.
TypedBuffer	This type provides an interface to create one of the buffer types from a raw harfbuzz pointer.

Glyph
GlyphExtents
Position