# makeover-tui

The terminal renderer for
[`makeover-layout`](https://makenot.work/git/max/makeover-layout), on ratatui.

Named for the target and not for the library, the same way `makeover-immediate`
is named for the mode and not for egui.

## What a terminal actually costs you

Not colour, on any terminal built this decade. Measured across the 31 shipped
themes
(`makeover`'s `well_fidelity` example):

| | ANSI-16 | ANSI-256 | truecolor |
|---|---|---|---|
| a well collapses onto its face | 18/31 | 4/31 | 2/31 |
| at least one bevel edge vanishes into its face | 31/31 | 4/31 | 0 |

The threshold is 256, not 24-bit. The two failures surviving at truecolor are
not terminal failures: they are the themes whose raised surface is already
white, so the lightening clamps and the well lands on its face. Those render
identically in a browser, and makeover already asserts them.

**What a terminal costs is geometry.** An edge occupies a whole cell per side,
and a cell is roughly 8x17 pixels, so a one-pixel bevel becomes an order of
magnitude heavier. `frame` returns a shrunk `Rect` rather than pretending the
region survived. There is nowhere to put a corner radius, so `radius_control`
and `radius_container` mean the same thing here. A fill begins and ends on a
cell boundary.

That is the constraint worth designing against. It does not improve, it is not
detectable, and it applies equally to the best terminal ever written.

## Where fidelity matters

At `Fidelity::Ansi16` the depth vocabulary collapses: a well cannot be filled
distinctly on most themes *and* a bevel loses an edge on all of them, so a
raised card and a well both read as one single-tone box. Colour cannot carry
the distinction, so `frame` carries it with the glyphs, doubling the frame for
a raised surface and leaving a well light. Above sixteen colours that fallback
never fires, which is tested, because a doubled frame on every modern terminal
would be shouting.

`Fidelity::detect()` reads `COLORTERM` then `TERM` and is deliberately
credulous. A terminal that understates itself costs a slightly heavier frame; a
terminal that overstates itself was going to render wrongly whatever this crate
assumed.

`Palette::shows` is not a low-colour workaround. It is a correctness check that
a fill will be visible against what is behind it, and at truecolor it fires on
exactly the two clamping themes, which is when it should.

## Substitution is renderer policy

Substituting one intent for another belongs to a renderer, never to the
description. Falling back from `Fill::Well` to `Page` is an answer for a
renderer that can always paint an exact colour; here it is wrong, because the
page is usually the surface a well is cut *into*, so the substitution produces
the invisibility it was meant to prevent. `makeover-immediate` wants that
fallback and this renderer does not.

## Status

On crates.io. Intended first consumers are alloy_tui and shop, both of which
already take makeover and makeover-geometry from the registry.

Design lives in the wiki note `makeover-tui`; the backlog is in GoingsOn under
the project of the same name.

## Licence

MIT.