Module indent_guides 

Indentation guides — the per-pane layer both renderers paint from.

See docs/dev/architecture/indent-guides.md (design) and docs/dev/operations/slice-plans/indent-guides.md (slices).

What this is

IndentGuides is the resolved answer to “which columns carry a guide on which rows, and which block is the cursor in”. It is built by cells_worker in the pass that builds the pane’s DisplayMatrix, from the same snapshot and stamped with the same MatrixVersion — so the two cannot disagree and guides need no staleness axis of their own.

Why the paint predicate is resolved here

IndentBlock::paints_on decides whether a guide may occupy a column, and getting it wrong means painting over text. Applying it in the producer rather than in each renderer means there is exactly one implementation: a bug surfaces as a failing test here rather than as corrupted text in one peer and not the other. What each renderer still owns is the mechanism — the TUI substitutes a glyph into a cell, the GPU peer paints a hairline quad — because a terminal cell cannot hold a one-pixel rule.

Why blocks are published alongside the per-row marks

The active guide is the innermost block containing the cursor, and the cursor moves at keystroke rate. Publishing extents rather than a precomputed “is active” flag lets each renderer pick the active block per frame from the cursor row it already holds — an integer scan over the blocks in the window — so cursor motion costs the worker nothing and the highlight has zero lag.

Structs

GuideMark

One guide occupying one column of one row.

IndentGuideInputs

The per-buffer inputs a guide layer is built from, resolved once per publish and carried on crate::render_state::PaneCellsInputs.

IndentGuides

The per-pane guide layer.

Functions

build_indent_guides

Build the guide layer for the source lines [lo, hi).

indent_axis_version

Hash the inputs that change the guides’ geometry.