render-ansi

render-ansi converts highlighted byte spans and resolved styles into ANSI/VT escaped terminal text.

What It Provides

End-to-end helpers:
- highlight_to_ansi(...) -> String
- highlight_to_ansi_with_mode(..., ColorMode::{TrueColor|Ansi256|Ansi16}) -> String
- highlight_lines_to_ansi_lines(...) -> Vec<String>
- highlight_lines_to_ansi_lines_with_mode(..., ColorMode::{TrueColor|Ansi256|Ansi16}) -> Vec<String>
- High-level highlight helpers treat normal as a base layer and fill uncovered ranges with that style.
- ANSI output intentionally ignores bg style fields so terminal background is not overridden.
Incremental patching:
- IncrementalRenderer::new(width, height)
- IncrementalRenderer::set_origin(row, col)
- IncrementalRenderer::set_color_mode(ColorMode::{TrueColor|Ansi256|Ansi16})
- IncrementalRenderer::render_patch(source, spans) -> String
- IncrementalRenderer::highlight_to_patch(...) -> String
Stream-safe single-line diff (no width/XY assumptions):
- StreamLineRenderer::new()
- StreamLineRenderer::render_line_patch(source, spans) -> String
- StreamLineRenderer::highlight_line_to_patch(...) -> String
Low-level render helpers:
- resolve_styled_spans(...)
- render_ansi(...)
- render_ansi_lines(...)

Quick Example

use highlight_spans::Grammar;
use render_ansi::{highlight_to_ansi_with_mode, ColorMode};
use theme_engine::load_theme;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let theme = load_theme("tokyonight-dark")?;
    let out = highlight_to_ansi_with_mode(
        b"SELECT 42",
        Grammar::Sql,
        &theme,
        ColorMode::Ansi256,
    )?;
    println!("{out}");
    Ok(())
}

When To Use This Crate

Use this crate when you want terminal-ready ANSI output.
Incremental patching computes cursor columns by display width (grapheme-aware), not raw bytes.
StreamLineRenderer uses relative single-line patching (CUB + overwrite + optional EL) and is useful when terminal width is unknown.
Tab cells are interpreted with an 8-column tab stop in the incremental path.
Default ANSI color mode is truecolor (38;2;r;g;b). Use Ansi256 or Ansi16 for constrained terminals.
If you have your own paint engine (for example native C), use highlight-spans + theme-engine directly and skip ANSI rendering.

Examples

show_highlight: full-frame ANSI render for a file.
zedit_bridge: machine-readable paint ops (start end fg_r fg_g fg_b bg_r bg_g bg_b flags).
vt_patch_bridge: incremental VT patch output using IncrementalRenderer.
stream_line_bridge: width-independent single-line patch output using StreamLineRenderer.

Incremental Origin Offset

If your editable text starts after a prompt (or inside a viewport sub-region), set an origin:

let mut renderer = render_ansi::IncrementalRenderer::new(120, 40);
renderer.set_origin(4, 7); // row 4, col 7 (1-based)

For the CLI bridge: