Function getRenderContext

src/interactiveHelpers.tsx:299–365

(exitOnCtrlC: boolean)

  return onboardingShown;
}
export function getRenderContext(exitOnCtrlC: boolean): {
  renderOptions: RenderOptions;
  getFpsMetrics: () => FpsMetrics | undefined;
  stats: StatsStore;
} {
  let lastFlickerTime = 0;
  const baseOptions = getBaseRenderOptions(exitOnCtrlC);

  // Log analytics event when stdin override is active
  if (baseOptions.stdin) {
    logEvent('tengu_stdin_interactive', {});
  }
  const fpsTracker = new FpsTracker();
  const stats = createStatsStore();
  setStatsStore(stats);

  // Bench mode: when set, append per-frame phase timings as JSONL for
  // offline analysis by bench/repl-scroll.ts. Captures the full TUI
  // render pipeline (yoga → screen buffer → diff → optimize → stdout)
  // so perf work on any phase can be validated against real user flows.
  const frameTimingLogPath = process.env.CLAUDE_CODE_FRAME_TIMING_LOG;
  return {
    getFpsMetrics: () => fpsTracker.getMetrics(),
    stats,
    renderOptions: {
      ...baseOptions,
      onFrame: event => {
        fpsTracker.record(event.durationMs);
        stats.observe('frame_duration_ms', event.durationMs);
        if (frameTimingLogPath && event.phases) {
          // Bench-only env-var-gated path: sync write so no frames dropped
          // on abrupt exit. ~100 bytes at ≤60fps is negligible. rss/cpu are
          // single syscalls; cpu is cumulative — bench side computes delta.
          const line =
          // eslint-disable-next-line custom-rules/no-direct-json-operations -- tiny object, hot bench path
          JSON.stringify({
            total: event.durationMs,
            ...event.phases,
            rss: process.memoryUsage.rss(),
            cpu: process.cpuUsage()
          }) + '\n';
          // eslint-disable-next-line custom-rules/no-sync-fs -- bench-only, sync so no frames dropped on exit
          appendFileSync(frameTimingLogPath, line);
        }
        // Skip flicker reporting for terminals with synchronized output —
        // DEC 2026 buffers between BSU/ESU so clear+redraw is atomic.
        if (isSynchronizedOutputSupported()) {
          return;
        }
        for (const flicker of event.flickers) {
          if (flicker.reason === 'resize') {
            continue;
          }
          const now = Date.now();
          if (now - lastFlickerTime < 1000) {
            logEvent('tengu_flicker', {
              desiredHeight: flicker.desiredHeight,
              actualHeight: flicker.availableHeight,