[PR #751] feat(core): expose no_zwj as opt-in WidthMethod #756

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opened 2026-03-02 23:47:59 +03:00 by kerem · 0 comments

kerem commented

2026-03-02 23:47:59 +03:00

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📋 Pull Request Information

Original PR: https://github.com/anomalyco/opentui/pull/751
Author: @Flare576
Created: 2/27/2026
Status: 🔄 Open

Base: main ← Head: feat/no-zwj-width-method

📝 Commits (1)

47cc0c2 feat(core): expose no_zwj as opt-in WidthMethod option

📊 Changes

4 files changed (+11 additions, -11 deletions)

View changed files

📝 packages/core/src/renderer.ts (+1 -1)
📝 packages/core/src/types.ts (+1 -1)
📝 packages/core/src/zig.ts (+4 -4)
📝 packages/core/src/zig/lib.zig (+5 -5)

📄 Description

Problem

ZWJ emoji sequences (👩‍🚀 👨‍👩‍👧 🏳️‍🌈) cause layout corruption in terminals that don't render them as joined glyphs — most notably tmux, but also many older terminals. Text after a ZWJ sequence shifts across the screen, wraps incorrectly, and input box spacing breaks.

The no_zwj width calculation mode already exists in the Zig layer, is fully implemented, and has comprehensive test coverage (utf8_no_zwj_test.zig). The environment variable OPENTUI_FORCE_NOZWJ is already registered and wired through terminal.zig. However, no_zwj is missing from the TypeScript WidthMethod union type and from the numeric mapping at the FFI boundary, making it completely unreachable from JavaScript consumers.

Solution

Wire no_zwj through the full TypeScript→FFI chain without changing any defaults:

packages/core/src/types.ts: Add "no_zwj" to the WidthMethod union
packages/core/src/zig.ts: Map "no_zwj" → 2 in the four widthMethodCode conversions (previously only 0/1 existed)
packages/core/src/zig/lib.zig: Map u8 value 2 → .no_zwj in the four FFI entry points; map .no_zwj → 2 in getTerminalCapabilities serialization
packages/core/src/renderer.ts: Update the widthMethod getter to return "no_zwj" when capabilities report 2 (e.g. via OPENTUI_FORCE_NOZWJ)

Behavior

Mode	ZWJ emoji (👩‍🚀)	Skin tones (👋🏿)	Flags (🇺🇸)	Accents (é)
`unicode` (default, unchanged)	1 glyph, 2 cols	1 glyph, 2 cols	1 glyph, 2 cols	1 glyph, 1 col
`no_zwj` (opt-in)	2 glyphs, 4 cols	1 glyph, 2 cols	1 glyph, 2 cols	1 glyph, 1 col

Only ZWJ-joined sequences are affected. Skin tone modifiers, regional indicator flags, combining accents, and CJK characters are all unaffected.

No Breaking Changes

Default is still "unicode" everywhere
"wcwidth" behavior is unchanged
OPENTUI_FORCE_NOZWJ env var now correctly round-trips through getTerminalCapabilities → widthMethod getter
Existing consumers passing "wcwidth" or "unicode" see identical behavior

Related to #609 (emoji wrap corruption at line boundaries)
Companion PR for OpenCode to expose this as a user config option: https://github.com/Flare576/opencode/tree/feat/no-zwj-width-method

_{🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.}

## 📋 Pull Request Information **Original PR:** https://github.com/anomalyco/opentui/pull/751 **Author:** [@Flare576](https://github.com/Flare576) **Created:** 2/27/2026 **Status:** 🔄 Open **Base:** `main` ← **Head:** `feat/no-zwj-width-method` --- ### 📝 Commits (1) - [`47cc0c2`](https://github.com/anomalyco/opentui/commit/47cc0c2cd0f0b8f20fd0e9d91b1d242204ca7e7a) feat(core): expose no_zwj as opt-in WidthMethod option ### 📊 Changes **4 files changed** (+11 additions, -11 deletions) <details> <summary>View changed files</summary> 📝 `packages/core/src/renderer.ts` (+1 -1) 📝 `packages/core/src/types.ts` (+1 -1) 📝 `packages/core/src/zig.ts` (+4 -4) 📝 `packages/core/src/zig/lib.zig` (+5 -5) </details> ### 📄 Description ## Problem ZWJ emoji sequences (👩‍🚀 👨‍👩‍👧 🏳️‍🌈) cause layout corruption in terminals that don't render them as joined glyphs — most notably tmux, but also many older terminals. Text after a ZWJ sequence shifts across the screen, wraps incorrectly, and input box spacing breaks. The `no_zwj` width calculation mode already exists in the Zig layer, is fully implemented, and has comprehensive test coverage (`utf8_no_zwj_test.zig`). The environment variable `OPENTUI_FORCE_NOZWJ` is already registered and wired through `terminal.zig`. However, `no_zwj` is missing from the TypeScript `WidthMethod` union type and from the numeric mapping at the FFI boundary, making it completely unreachable from JavaScript consumers. ## Solution Wire `no_zwj` through the full TypeScript→FFI chain without changing any defaults: - **`packages/core/src/types.ts`**: Add `"no_zwj"` to the `WidthMethod` union - **`packages/core/src/zig.ts`**: Map `"no_zwj"` → `2` in the four `widthMethodCode` conversions (previously only `0`/`1` existed) - **`packages/core/src/zig/lib.zig`**: Map `u8` value `2` → `.no_zwj` in the four FFI entry points; map `.no_zwj` → `2` in `getTerminalCapabilities` serialization - **`packages/core/src/renderer.ts`**: Update the `widthMethod` getter to return `"no_zwj"` when capabilities report `2` (e.g. via `OPENTUI_FORCE_NOZWJ`) ## Behavior | Mode | ZWJ emoji (👩‍🚀) | Skin tones (👋🏿) | Flags (🇺🇸) | Accents (é) | |---|---|---|---|---| | `unicode` (default, unchanged) | 1 glyph, 2 cols | 1 glyph, 2 cols | 1 glyph, 2 cols | 1 glyph, 1 col | | `no_zwj` (opt-in) | 2 glyphs, 4 cols | 1 glyph, 2 cols | 1 glyph, 2 cols | 1 glyph, 1 col | Only ZWJ-joined sequences are affected. Skin tone modifiers, regional indicator flags, combining accents, and CJK characters are all unaffected. ## No Breaking Changes - Default is still `"unicode"` everywhere - `"wcwidth"` behavior is unchanged - `OPENTUI_FORCE_NOZWJ` env var now correctly round-trips through `getTerminalCapabilities` → `widthMethod` getter - Existing consumers passing `"wcwidth"` or `"unicode"` see identical behavior ## Related - Related to #609 (emoji wrap corruption at line boundaries) - Companion PR for OpenCode to expose this as a user config option: https://github.com/Flare576/opencode/tree/feat/no-zwj-width-method --- <sub>🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.</sub>