Module render 

Plain-frame render assembly — M1-5 implementation per ADR-2.

Module structure

• cli_boxes — vendored cli-boxes@4.0.1 char table (border drawing chars).
• grid — char grid: write/clip/wide-char cleanup/get (output.ts port).
• border — border char drawing (render-border.ts port, plain slice).
• walk — arena tree walk → grid (render-node-to-output.ts port).
• mod (this) — render_to_string entry point tying layout + grid together.

Engine-per-call design (ADR-3, M3-A)

Both render_to_string and the build_layout_engine seam create a fresh TaffyEngine on each call. ADR-3 (docs/adr3-engine-lifetime.md) chose per-frame rebuild over a live incremental engine: persistence lives in the Arena (which InkRoot will own across commit() calls, M3-D), while the engine is a pure function of the arena at render time. A fresh engine re-runs set_measure for every text node every frame, so the measure-invalidation discipline (layout/engine.rs:78-82) is satisfied for free — the rejected incremental option would have had to replicate it by hand, at the risk of silent text-measure corruption. The node-creation walk is NEVER re-run against an already-populated engine: insert_child appends, so reuse would duplicate child lists. See ADR-3 for the full rationale.

Height for unconstrained render (render-to-string.ts:62-68 citation)

ink’s renderToString calls:

rootNode.yogaNode!.calculateLayout(undefined, undefined, Yoga.DIRECTION_LTR);

ink passes undefined for both axes in yoga, but the root node has an explicit setWidth(columns) call immediately before (render-to-string.ts:62), so in practice width is definite and only height is unconstrained. render_to_string mirrors this: width is AvailableSpace::Definite(columns), height is AvailableSpace::MaxContent (passed as None to calculate). The grid is sized to the computed root height so trailing empty rows are never included in the output.

Re-exports

pub use colorize::ColorLevel;

pub use colorize::Kind as ColorKind;

pub use colorize::colorize;

pub use colorize::dim;

Modules

background

Box background-fill rendering — port of ink’s render-background.ts.

border

Border rendering — styled-frame slice.

cli_boxes

Vendored cli-boxes character table.

colorize

Chalk SGR emission — port of ink/src/colorize.ts.

grid

Char grid — plain-frame output assembly.

walk

Tree walk — plain-frame render pass.

Functions

build_layout_engine

Build a fresh layout engine for the arena tree rooted at root_id, compute layout at the given width, and return the built engine plus the root rect.

render_static

Render the static subtree (ink’s <Static>) to its standalone output string — the text ink prints once, above the live region.

render_styled

Render the arena tree rooted at root_id to a styled frame, returning both the frame string and its height in rows (mirrors ink's {output, height}, output.ts:315-316). This is the entry M3-E render_frame` calls.

render_to_string

Render the arena tree rooted at root_id to a plain-frame string.