Crate text_typeset 

text-typeset

Turns rich text documents into GPU-ready glyph quads.

Typesetting crate for the text-document ecosystem. Takes a rich text document model (styled paragraphs, tables, lists, frames) and produces positioned glyph quads, decoration rectangles, and a glyph atlas texture that any GPU framework can render in a few draw calls.

text-document (model) --> text-typeset (shaping + layout) --> framework adapter (rendering)

Architecture: shared service, owned flows

text-typeset is split along the axis of “what is shareable”:

• TextFontService owns the font registry, the glyph atlas, the glyph cache, the swash scale context, and the HiDPI scale factor. It is the expensive-to-build, expensive-to-share part. Construct one per process (or one per window) and share it by reference across every widget that emits text.

• DocumentFlow owns the per-widget view state: viewport, zoom, scroll offset, content-width mode, flow layout, cursor, and default colors. Every widget that shows a document holds its own DocumentFlow. Layout and render methods take the service by reference, so many flows can render into one shared atlas — which means one GPU upload per frame, one shaped glyph rasterized at most once, and no cross-widget contamination of viewport / zoom / scroll state.

Quick start

use text_typeset::{DocumentFlow, TextFontService};

let mut service = TextFontService::new();
let face = service.register_font(include_bytes!("../test-fonts/NotoSans-Variable.ttf"));
service.set_default_font(face, 16.0);

let mut flow = DocumentFlow::new();
flow.set_viewport(800.0, 600.0);

let doc = text_document::TextDocument::new();
doc.set_plain_text("Hello, world!").unwrap();
flow.layout_full(&service, &doc.snapshot_flow());

let frame = flow.render(&mut service);
// frame.glyphs       -> glyph quads (textured rects from the shared atlas)
// frame.atlas_pixels -> RGBA texture to upload (or skip via service.atlas_pixels())
// frame.decorations  -> cursor, selection, underlines, borders

Sharing between widgets

Put the service behind whatever smart pointer the host framework uses — an Rc<RefCell<TextFontService>> for single-threaded UIs, a plain &mut in render loops that already have exclusive access. Every widget owns its own DocumentFlow and calls flow.render(&mut *service.borrow_mut()) when it paints.

Because the service does not store any per-widget state, “widget A rendered last” cannot break widget B. A changes to set_viewport, set_zoom, set_scroll_offset, or set_cursor live on A’s flow and never touch B’s.

Features

• text-document (default): enables bridge module and DocumentFlow::layout_full for direct integration with text-document’s FlowSnapshot.

Re-exports

pub use layout::inline_markup::InlineAttrs;

pub use layout::inline_markup::InlineMarkup;

pub use layout::inline_markup::InlineSpan;

Modules

atlas

bridge

Bridge between text-document snapshot types and text-typeset layout params.

font

layout

shaping

Structs

AtlasSnapshot

Outcome of a call to TextFontService::atlas_snapshot.

BlockVisualInfo

Visual position and size of a laid-out block.

CharacterGeometry

Per-character advance geometry for a laid-out text run.

CursorDisplay

Cursor display state for rendering.

DecorationRect

A colored rectangle for decorations (underlines, selections, borders, etc.).

DocumentFlow

Per-widget document flow state.

FontFaceId

Opaque handle to a registered font face.

GlyphQuad

A positioned glyph to draw as a textured quad from the atlas.

HitTestResult

Result of [crate::Typesetter::hit_test] - maps a screen-space point to a document position.

ImageQuad

An inline image placeholder.

LaidOutSpan

A single laid-out span produced by the markup-aware layout path.

ParagraphResult

Result of [crate::Typesetter::layout_paragraph].

RenderFrame

Everything needed to draw one frame.

SingleLineResult

Result of [crate::Typesetter::layout_single_line].

TextFontService

Shared font resources for a text-typeset session.

TextFormat

Text formatting parameters for the single-line layout API.

Enums

ContentWidthMode

How the content (layout) width is determined.

DecorationKind

The type of a DecorationRect.

HitRegion

What region of the layout a hit test landed in.

LaidOutSpanKind

Kind discriminator for LaidOutSpan.

RelayoutError

Reasons DocumentFlow::relayout_block may refuse an incremental update.

UnderlineStyle

Underline style for text decorations.

VerticalAlignment

Vertical alignment for characters (superscript, subscript, etc.).