Crate cosmic_text

Expand description

§COSMIC Text

This library provides advanced text handling in a generic way. It provides abstractions for shaping, font discovery, font fallback, layout, rasterization, and editing. Shaping utilizes rustybuzz, font discovery utilizes fontdb, and the rasterization is optional and utilizes swash. The other features are developed internal to this library.

It is recommended that you start by creating a FontSystem, after which you can create a Buffer, provide it with some text, and then inspect the layout it produces. At this point, you can use the SwashCache to rasterize glyphs into either images or pixels.

use cosmic_text::{Attrs, Color, FontSystem, SwashCache, Buffer, Metrics, Shaping};

// A FontSystem provides access to detected system fonts, create one per application
let mut font_system = FontSystem::new();

// A SwashCache stores rasterized glyphs, create one per application
let mut swash_cache = SwashCache::new();

// Text metrics indicate the font size and line height of a buffer
let metrics = Metrics::new(14.0, 20.0);

// A Buffer provides shaping and layout for a UTF-8 string, create one per text widget
let mut buffer = Buffer::new(&mut font_system, metrics);

// Borrow buffer together with the font system for more convenient method calls
let mut buffer = buffer.borrow_with(&mut font_system);

// Set a size for the text buffer, in pixels
buffer.set_size(Some(80.0), Some(25.0));

// Attributes indicate what font to choose
let attrs = Attrs::new();

// Add some text!
buffer.set_text("Hello, Rust! 🦀\n", attrs, Shaping::Advanced);

// Perform shaping as desired
buffer.shape_until_scroll(true);

// Inspect the output runs
for run in buffer.layout_runs() {
    for glyph in run.glyphs.iter() {
        println!("{:#?}", glyph);
    }
}

// Create a default text color
let text_color = Color::rgb(0xFF, 0xFF, 0xFF);

// Draw the buffer (for performance, instead use SwashCache directly)
buffer.draw(&mut swash_cache, text_color, |x, y, w, h, color| {
    // Fill in your code here for drawing rectangles
});

Re-exports§

pub use ttf_parser;
pub use fontdb;
pub use rustybuzz;

Structs§

Angle: Represents an angle in degrees or radians.
Attrs: Text attributes
AttrsList: List of text attributes to apply to a line
AttrsOwned: An owned version of Attrs
BidiParagraphs: An iterator over the paragraphs in the input text. It is equivalent to core::str::Lines but follows unicode-bidi behaviour.
BorrowedWithFontSystem: A value borrowed together with an FontSystem
Buffer: A buffer of text that is shaped and laid out
BufferLine: A line (or paragraph) of text that is shaped and laid out
CacheKey: Key for building a glyph cache
CacheKeyFlags: Flags that change rendering
CacheMetrics: Metrics, but implementing Eq and Hash using u32 representation of f32
Change: A set of change items grouped into one logical change
ChangeItem: A unique change to an editor
Color: Text color
Cursor: Current cursor location
Editor: A wrapper of [Buffer] for easy editing
Font: A font
FontMatchAttrs: Font-specific part of Attrs to be used for matching
FontMatchKey
FontSystem: Access to the system fonts.
LayoutCursor: The position of a cursor within a [Buffer].
LayoutGlyph: A laid out glyph
LayoutLine: A line of laid out glyphs
LayoutRun: A line of visible text for rendering
LayoutRunIter: An iterator of visible text lines, see LayoutRun
LineIter: Iterator over lines terminated by LineEnding
Metrics: Metrics of text
PhysicalGlyph
Placement: Describes the offset and dimensions of a rendered mask.
Scroll: Scroll position in [Buffer]
ShapeBuffer: A set of buffers containing allocations for shaped text.
ShapeGlyph: A shaped glyph
ShapeLine: A shaped line (or paragraph)
ShapeRunCache: A helper structure for caching shape runs.
ShapeRunKey: Key for caching shape runs.
ShapeSpan: A shaped span (for bidirectional processing)
ShapeWord: A shaped word (for word wrapping)
SwashCache: Cache for rasterizing with the swash scaler
SwashImage: Scaled glyph image.
SyntaxEditor: A wrapper of Editor with syntax highlighting provided by SyntaxSystem
SyntaxSystem
SyntaxTheme: A theme parsed from a .tmTheme file.
Transform: Two dimensional transformation matrix.
ViEditor
ViParser
Weight: Specifies the weight of glyphs in the font, their degree of blackness or stroke thickness.

Enums§

Action: An action to perform on an Editor
Affinity: Whether to associate cursors placed at a boundary between runs with the run before or after it.
Align: Align or justify
BufferRef
Command: Path command.
Family: A font family.
FamilyOwned: An owned version of Family
LineEnding: Line ending
Motion: A motion to perform on a Cursor
Selection: Selection mode
Shaping: The shaping strategy of some text.
Stretch: A face width.
Style: Allows italic or oblique faces to be selected.
SubpixelBin: Binning of subpixel position for cache optimization
SwashContent: Content of a scaled glyph image.
ViMode
Wrap: Wrapping mode

Traits§