Function keepsMoving

packages/cli/src/utils/motionAudit.ts:164–208

(
  frames: MotionFrame[],
  within: string | undefined,
  maxStaticSec: number,
)

}

function keepsMoving(
  frames: MotionFrame[],
  within: string | undefined,
  maxStaticSec: number,
): LayoutIssue[] {
  // "*" is reserved for whole-canvas scope; motionSpec.ts rejects it as a user-supplied withinSelector.
  const scope = within ?? "*";
  if (within && frames.every((frame) => !frame.liveness[scope])) {
    return [missingIssue(within, 0)];
  }

  const issues: LayoutIssue[] = [];
  const first = frames[0];
  if (!first) return issues;
  let runStart = first.time;
  let runSig = first.liveness[scope] ?? "";
  const flush = (endTime: number) => {
    const span = endTime - runStart;
    if (span > maxStaticSec) {
      issues.push({
        code: "motion_frozen",
        severity: "error",
        time: runStart,
        selector: within ?? "composition",
        message: `nothing moves${within ? ` within ${within}` : ""} between ${round(runStart)}s and ${round(endTime)}s (${round(span)}s static) — should keep moving`,
        rect: ZERO_RECT,
        fixHint:
          "Add or extend motion so no shot freezes for this long, or shorten the static hold.",
      });
    }
  };

  let lastTime = runStart;
  for (const frame of frames.slice(1)) {
    lastTime = frame.time;
    const sig = frame.liveness[scope] ?? "";
    if (sig !== runSig) {
      flush(frame.time);
      runStart = frame.time;
      runSig = sig;
    }
  }
  flush(lastTime);
  return issues;
}

/**
 * Evaluate motion assertions against the dense `element × time` matrix.