Function diffRowBoth

src/ink/screen.ts:1230–1256

* Diff one row where both screens are in bounds. * Scans for differences with findNextDiff, unpacks and calls cb for each.

(
  prevCells: Int32Array,
  nextCells: Int32Array,
  prev: Screen,
  next: Screen,
  ci: number,
  y: number,
  startX: number,
  endX: number,
  prevCell: Cell,
  nextCell: Cell,
  cb: DiffCallback,
)

 * Scans for differences with findNextDiff, unpacks and calls cb for each.
 */
function diffRowBoth(
  prevCells: Int32Array,
  nextCells: Int32Array,
  prev: Screen,
  next: Screen,
  ci: number,
  y: number,
  startX: number,
  endX: number,
  prevCell: Cell,
  nextCell: Cell,
  cb: DiffCallback,
): boolean {
  let x = startX
  while (x < endX) {
    const skip = findNextDiff(prevCells, nextCells, ci, endX - x)
    x += skip
    ci += skip << 1
    if (x >= endX) break
    cellAtCI(prev, ci, prevCell)
    cellAtCI(next, ci, nextCell)
    if (cb(x, y, prevCell, nextCell)) return true
    x++
    ci += 2
  }
  return false
}

/**
 * Emit removals for a row that only exists in prev (height shrank).