Fix flicker issues by ensuring all actively changing content fits in the viewport (#1217)

packages/cli/src/ui/components/shared/text-buffer.ts

@@ -12,6 +12,7 @@ import pathMod from 'path';
 import { useState, useCallback, useEffect, useMemo } from 'react';
 import stringWidth from 'string-width';
 import { unescapePath } from '@gemini-cli/core';
+import { toCodePoints, cpLen, cpSlice } from '../../utils/textUtils.js';
 
 export type Direction =
   | 'left'
@@ -69,28 +70,6 @@ function clamp(v: number, min: number, max: number): number {
   return v < min ? min : v > max ? max : v;
 }
 
-/*
- * -------------------------------------------------------------------------
- *  Unicode‑aware helpers (work at the code‑point level rather than UTF‑16
- *  code units so that surrogate‑pair emoji count as one "column".)
- * ---------------------------------------------------------------------- */
-
-export function toCodePoints(str: string): string[] {
-  // [...str] or Array.from both iterate by UTF‑32 code point, handling
-  // surrogate pairs correctly.
-  return Array.from(str);
-}
-
-export function cpLen(str: string): number {
-  return toCodePoints(str).length;
-}
-
-export function cpSlice(str: string, start: number, end?: number): string {
-  // Slice by code‑point indices and re‑join.
-  const arr = toCodePoints(str).slice(start, end);
-  return arr.join('');
-}
-
 /* -------------------------------------------------------------------------
  *  Debug helper – enable verbose logging by setting env var TEXTBUFFER_DEBUG=1
  * ---------------------------------------------------------------------- */