diff --git a/system/ui/lib/application.py b/system/ui/lib/application.py index 4fbfbc0de..5d40abdc1 100644 --- a/system/ui/lib/application.py +++ b/system/ui/lib/application.py @@ -169,6 +169,10 @@ class MouseState: self._rk.keep_time() def _handle_mouse_event(self): + # TODO: read touch events from evdev directly to get real kernel timestamps. + # Polling at 140Hz with time.monotonic() causes timing jitter that makes scroll + # velocity oscillate (alternating high/low). Real timestamps would also let us + # detect swipe-stop-lift via event gaps instead of the fragile decel heuristic. for slot in range(MAX_TOUCH_SLOTS): mouse_pos = rl.get_touch_position(slot) x = mouse_pos.x / self._scale if self._scale != 1.0 else mouse_pos.x diff --git a/system/ui/lib/scroll_panel2.py b/system/ui/lib/scroll_panel2.py index e2a548ba2..18fd8a9a6 100644 --- a/system/ui/lib/scroll_panel2.py +++ b/system/ui/lib/scroll_panel2.py @@ -20,6 +20,21 @@ MAX_SPEED = 10000.0 # px/s DEBUG = os.getenv("DEBUG_SCROLL", "0") == "1" +# Weights older (steadier) velocity samples more heavily on release. +# Finger-lift samples are noisy; trusting earlier samples gives consistent fling velocity. +# Reverse-engineered from iOS UIScrollView (tuned at 120Hz touch) by Flutter team: +# https://github.com/flutter/flutter/pull/60501 +# 3 samples ≈ 25ms at 120Hz (iOS) / ~21ms at 140Hz (comma). Scale if touch rate changes. +def weighted_velocity(buffer: deque) -> float: + if len(buffer) >= 3: + return buffer[-3] * 0.6 + buffer[-2] * 0.35 + buffer[-1] * 0.05 + elif len(buffer) == 2: + return buffer[-2] * 0.7 + buffer[-1] * 0.3 + elif len(buffer) == 1: + return buffer[-1] + return 0.0 + + # from https://ariya.io/2011/10/flick-list-with-its-momentum-scrolling-and-deceleration class ScrollState(Enum): STEADY = 0 @@ -151,7 +166,13 @@ class GuiScrollPanel2: # Touch rejection: when releasing finger after swiping and stopping, panel # reports a few erroneous touch events with high velocity, try to ignore. - # If velocity decelerates very quickly, assume user doesn't intend to auto scroll + # If velocity decelerates very quickly, assume user doesn't intend to auto scroll. + # Catches two cases: 1) swipe, stop finger, then lift (stale high velocity in buffer) + # 2) dirty finger lift where finger rotates/slides producing spurious velocity spike. + # TODO: this heuristic false-positives on fast swipes because 140Hz touch polling + # jitter causes velocity to oscillate (not real deceleration). Better approaches: + # - Use evdev kernel timestamps to eliminate velocity oscillation at the source + # - Replace with a time-since-last-event check (40ms timeout) for swipe-stop-lift high_decel = False if len(self._velocity_buffer) > 2: # We limit max to first half since final few velocities can surpass first few @@ -166,6 +187,8 @@ class GuiScrollPanel2: print('deceleration too high, going to STEADY') high_decel = True + self._velocity = weighted_velocity(self._velocity_buffer) + # If final velocity is below some threshold, switch to steady state too low_speed = abs(self._velocity) <= MIN_VELOCITY_FOR_CLICKING * 1.5 # plus some margin