Function shouldClearScreen

src/ink/frame.ts:105–124

(
  prevFrame: Frame,
  frame: Frame,
)

 * 3. Previous frame screen height exceeded available terminal rows → 'offscreen'
 */
export function shouldClearScreen(
  prevFrame: Frame,
  frame: Frame,
): FlickerReason | undefined {
  const didResize =
    frame.viewport.height !== prevFrame.viewport.height ||
    frame.viewport.width !== prevFrame.viewport.width
  if (didResize) {
    return 'resize'
  }

  const currentFrameOverflows = frame.screen.height >= frame.viewport.height
  const previousFrameOverflowed =
    prevFrame.screen.height >= prevFrame.viewport.height
  if (currentFrameOverflows || previousFrameOverflowed) {
    return 'offscreen'
  }

  return undefined
}