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MLP206: Literal play duration shorter than one frame

qual reports MLP206 when a Scene.play / Scene.wait call has a literal positive duration that is provably shorter than one frame period at every analyzed profile's frame rate.

The frame grid is np.arange(0, run_time, 1/frame_rate): a run time below one frame period still renders exactly one frame, sampled at t = 0 — the video shows a single frame near the animation's start state. Animation.finish() afterwards moves the live geometry to its final state but writes no additional video frame, so the intended motion (and its end state) never appears on screen, while the whole per-play startup (argument compile, hash, begin copies, cleanup, partial stream) is paid for that single frame of output.

  • Default severity: warning
  • Minimum confidence: certain
  • Implementation phase: 3
  • Fix: none

Zero and negative literal durations are a runtime ValueError and belong to MLC104, not this rule. A duration that is not a literal at the call site (a variable, a computed value) stays silent — the clamp is only reported when it is provable.

Wrong

class Demo(Scene):
    def construct(self):
        square = Square()
        self.play(FadeIn(square), run_time=0.004)  # < 1/60 s at 60 fps

class Demo(Scene):
    def construct(self):
        square = Square()
        self.play(FadeIn(square), run_time=0.5)