Scroll pedalboard/snapshot titles only when selected

CHANGELOG.md

@@ -4,6 +4,12 @@ Notable user visible changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+### Changed
+- Pedalboard/snapshot titles now auto-scroll only while selected with the NAV encoder (at most one thing scrolls at a time, and they sit at their leftmost position otherwise) — LCD updates over SPI are audible on the DAC at high gain, so the screen stays quiet while you play
+### Fixed
+- Long titles scrolled slightly past their last pixel before bouncing back; the scroll window now matches the drawn text area exactly
+
 ## [v3.3.1] - 2026-08-14
 ### Fixed
 - Pedalboards list no longer shows deleted pedalboards after they are removed from MOD-UI

docs/lcd_worker_thread.md

@@ -5,6 +5,8 @@
 A full-frame push blocks the UI thread for **21.4 ms on v2** and **25.2 ms on v3**,
 against a 10 ms tick. Nothing mitigates this today.
 
+LCD SPI transfers can be audible through the DAC at high gain, so avoid LCD updates that are not associated with the user's input.
+
 `PanelStack.propagate_dirty` gates pushes on `transfer_ms(clip) <= INLINE_BUDGET_MS`
 (8 ms), which *looks* like it protects the poll loop. It doesn't. The deferred path
 — `poll_lcd_updates()` → `flush()` → `lcd.update()` — runs on the **same UI thread**

pistomp/lcd320x240.py

@@ -282,10 +282,11 @@ def poll_updates(self):
     def _poll_updates(self):
         for d in self.w_parameter_dialogs.values():
             d.tick()
-        if self.w_pedalboard is not None:
-            self.w_pedalboard.tick()
-        if self.w_preset is not None:
-            self.w_preset.tick()
+        if self.pstack.current is self.main_panel:
+            if self.w_pedalboard is not None:
+                self.w_pedalboard.tick()
+            if self.w_preset is not None:
+                self.w_preset.tick()
         for wfs in self.w_footswitches:
             wfs.tick()
 
@@ -481,7 +482,6 @@ def draw_pedalboard(self, pedalboard_name):
                 font=self.title_font,
                 parent=self.main_panel,
                 action=self.draw_pedalboard_menu,
-                lcd_poll_divisor=self.poll_divisor,
                 subtitle="Pedalboard",
             )
             self.main_panel.add_sel_widget(self.w_pedalboard)
@@ -514,7 +514,6 @@ def draw_preset(self, preset_name):
             font=self.title_font,
             parent=self.main_panel,
             action=self.draw_preset_menu,
-            lcd_poll_divisor=self.poll_divisor,
             subtitle="Snapshot",
         )
         self.main_panel.add_sel_widget(self.w_preset)

tests/conftest.py

@@ -5,7 +5,9 @@
 
 import os
 import sys
+import time
 from pathlib import Path
+from typing import Protocol
 from unittest.mock import MagicMock
 
 import numpy as np
@@ -233,6 +235,29 @@ def fake_lcd():
     return FakeLcd()
 
 
+class Tickable(Protocol):
+    def tick(self) -> None: ...
+
+
+class FakeClock:
+    def __init__(self, monkeypatch: pytest.MonkeyPatch, start: float = 0.0) -> None:
+        self.now = start
+        monkeypatch.setattr(time, "monotonic", lambda: self.now)
+
+    def advance(self, dt: float) -> None:
+        self.now += dt
+
+    def drive(self, widget: Tickable, dt: float, n: int = 1) -> None:
+        for _ in range(n):
+            self.advance(dt)
+            widget.tick()
+
+
+@pytest.fixture
+def fake_clock(monkeypatch: pytest.MonkeyPatch) -> FakeClock:
+    return FakeClock(monkeypatch)
+
+
 # ---------------------------------------------------------------------------
 # Shared factory fixtures (available to all test directories)
 # ---------------------------------------------------------------------------

tests/test_lcd320x240.py

@@ -832,3 +832,122 @@ def test_tall_parallel_scrolled_to_last(lcd, snapshot):
     for _ in range(col0_count - 1 + 3):
         instance.main_panel.sel_next()
     snapshot("scrolled_to_last")
+
+
+@pytest.fixture
+def long_title_lcd(lcd, fake_clock):
+    instance, fake = lcd
+    pb = _make_pedalboard("The Extremely Long Pedalboard Name That Will Not Fit", [], [])
+    _setup_pedalboard(instance, pb)
+    instance.main_panel.sel_widget(instance.w_wrench)
+    for _ in range(20):
+        fake_clock.advance(0.08)
+        instance._poll_updates()
+    fake.frames.clear()
+    return instance, fake
+
+
+def test_long_title_stays_still_until_selected(long_title_lcd, fake_clock):
+    instance, fake = long_title_lcd
+    title = instance.w_pedalboard
+    assert title is not None and title._should_scroll()
+
+    for _ in range(100):
+        fake_clock.advance(0.08)
+        instance._poll_updates()
+    assert fake.frames == []
+    assert title.scroll_offset == 0
+
+
+def test_long_title_scrolls_only_while_selected(long_title_lcd, fake_clock):
+    instance, fake = long_title_lcd
+    title = instance.w_pedalboard
+    assert title is not None
+
+    def settle():
+        for _ in range(20):
+            fake_clock.advance(0.08)
+            instance._poll_updates()
+        fake.frames.clear()
+
+    for _ in range(25):
+        fake_clock.advance(0.08)
+        instance._poll_updates()
+    assert title.scroll_offset == 0
+    assert fake.frames == []
+
+    instance.main_panel.input_step(1, 1, 1.0)
+    assert instance.main_panel.sel_ref is title
+    assert title.selected
+    settle()
+
+    for _ in range(35):
+        fake_clock.advance(0.08)
+        instance._poll_updates()
+    assert title.scroll_offset > 0
+    assert len(fake.frames) > 0
+
+    instance.main_panel.input_step(1, 1, 1.0)
+    assert not title.selected
+    assert title.scroll_offset == 0
+    settle()
+    for _ in range(50):
+        fake_clock.advance(0.08)
+        instance._poll_updates()
+    assert fake.frames == []
+    assert title.scroll_offset == 0
+    fake.frames.clear()
+
+
+def test_title_does_not_tick_off_main_panel(long_title_lcd, fake_clock):
+    instance, fake = long_title_lcd
+    title = instance.w_pedalboard
+    assert title is not None
+    instance.main_panel.sel_widget(title)
+    for _ in range(35):
+        fake_clock.advance(0.08)
+        instance._poll_updates()
+    assert title.scroll_offset > 0
+    fake.frames.clear()
+
+    instance.pstack.current = None
+    offset = title.scroll_offset
+    for _ in range(50):
+        fake_clock.advance(0.08)
+        instance._poll_updates()
+    assert title.scroll_offset == offset
+    assert fake.frames == []
+
+def test_at_most_one_title_scrolls(long_title_lcd, fake_clock):
+    instance, _ = long_title_lcd
+    instance.draw_preset("An Equally Long Snapshot Name That Overflows")
+    pb_title = instance.w_pedalboard
+    preset_title = instance.w_preset
+    assert pb_title is not None and preset_title is not None
+    assert pb_title._should_scroll() and preset_title._should_scroll()
+
+    def moving():
+        return [w for w in (pb_title, preset_title) if w.scroll_offset != 0]
+
+    instance.main_panel.sel_widget(instance.w_wrench)
+    for _ in range(100):
+        fake_clock.advance(0.08)
+        instance._poll_updates()
+    assert moving() == []
+
+    instance.main_panel.sel_widget(pb_title)
+    for _ in range(120):
+        fake_clock.advance(0.08)
+        instance._poll_updates()
+        assert len(moving()) <= 1
+        assert preset_title.scroll_offset == 0
+    assert pb_title.scroll_offset > 0
+
+    instance.main_panel.sel_widget(preset_title)
+    assert pb_title.scroll_offset == 0
+    for _ in range(120):
+        fake_clock.advance(0.08)
+        instance._poll_updates()
+        assert len(moving()) <= 1
+        assert pb_title.scroll_offset == 0
+    assert preset_title.scroll_offset > 0

tests/test_scrolling_text.py

@@ -0,0 +1,179 @@
+
+import pytest
+
+from common.fonts import font_path
+from tests.conftest import FakeClock
+from uilib.box import Box
+from uilib.panel import Panel
+from uilib.pygame_init import font as make_font
+from uilib.text import ScrollingText
+
+
+LONG = "The Extremely Long Pedalboard Name That Will Not Fit"
+SHORT = "Rig"
+
+DT = 0.1
+
+
+@pytest.fixture
+def font():
+    return make_font(font_path("DejaVuSans.ttf"), 26)
+
+
+def make_text(font, text=LONG, width=60, parent=None):
+    w = ScrollingText(
+        box=Box.xywh(0, 0, width, 36),
+        text=text,
+        font=font,
+        parent=parent,
+    )
+    assert w.box is not None
+    return w
+
+
+def make_panel():
+    p = Panel(box=Box.xywh(0, 0, 320, 240))
+    p.visible = True
+    return p
+
+
+def max_offset_of(w):
+    h_margin, _ = w._get_margins()
+    return w.cached_text_width - (w.box.width - h_margin - w.outline)
+
+
+@pytest.fixture
+def clock(monkeypatch):
+    return FakeClock(monkeypatch)
+
+
+
+
+def test_unselected_never_scrolls(clock, font):
+    w = make_text(font)
+    w._render_text_to_cache()
+    assert w._should_scroll(), "fixture must overflow"
+
+    end = w.pause_start_sec + (max_offset_of(w) / w.pixels_per_second) * 2 + w.pause_end_sec + 5.0
+    t = 0.0
+    while t < end:
+        t += DT
+        clock.now = t
+        w.tick()
+        assert w.scroll_offset == 0, f"unselected widget scrolled to {w.scroll_offset} at t={t}"
+
+
+def test_hidden_never_scrolls(clock, font):
+    w = make_text(font)
+    w.selected = True
+    w.visible = False
+    clock.drive(w, DT, n=60)
+    assert w.scroll_offset == 0
+
+
+
+
+def test_selected_scrolls_and_pingpongs(clock, font):
+    w = make_text(font)
+    w._render_text_to_cache()
+    w.selected = True
+
+    max_off = max_offset_of(w)
+    scroll_dur = max_off / w.pixels_per_second
+
+    clock.drive(w, DT)
+    t0 = clock.now
+
+    while clock.now < t0 + w.pause_start_sec:
+        clock.drive(w, DT)
+    assert w.scroll_offset == 0
+
+    last = 0
+    t_end = t0 + w.pause_start_sec + scroll_dur
+    while clock.now < t_end:
+        clock.drive(w, DT)
+        assert w.scroll_offset >= last
+        last = w.scroll_offset
+    clock.now = t_end
+    w.tick()
+    assert w.scroll_offset == max_off
+
+    while clock.now < t_end + w.pause_end_sec:
+        clock.drive(w, DT)
+    assert w.scroll_offset == max_off
+
+    t_home = t_end + w.pause_end_sec + scroll_dur
+    while clock.now < t_home:
+        clock.drive(w, DT)
+    clock.now = t_home
+    w.tick()
+    assert w.scroll_offset == 0
+
+
+def test_text_that_fits_never_scrolls(clock, font):
+    w = make_text(font, text=SHORT, width=200)
+    w.selected = True
+    clock.drive(w, DT, n=100)
+    assert w.scroll_offset == 0
+
+
+
+
+def test_deselect_snaps_home_and_stays(clock, font):
+    w = make_text(font)
+    w._render_text_to_cache()
+    w.selected = True
+
+    max_off = max_offset_of(w)
+    clock.drive(w, DT)
+    t0 = clock.now
+    while clock.now < t0 + w.pause_start_sec + max_off / w.pixels_per_second:
+        clock.drive(w, DT)
+    assert w.scroll_offset == max_off
+
+    w.set_selected(False)
+    assert w.scroll_offset == 0
+
+    clock.drive(w, DT, n=200)
+    assert w.scroll_offset == 0
+    assert w._anchor_time is None
+
+
+
+
+def test_panel_selection_moves_the_single_scroller(clock, font):
+    panel = make_panel()
+    a = make_text(font, parent=panel, width=60)
+    b = make_text(font, parent=panel, width=60)
+    panel.add_sel_widget(a)
+    panel.add_sel_widget(b)
+    panel.sel_ref = a
+    a.selected = True
+    a._render_text_to_cache()
+    b._render_text_to_cache()
+
+    def offsets():
+        return (a.scroll_offset, b.scroll_offset)
+
+    clock.drive(a, DT, n=int((a.pause_start_sec + max_offset_of(a) / a.pixels_per_second * 0.5) / DT))
+    oa, ob = offsets()
+    assert oa > 0
+    assert ob == 0
+
+    panel.sel_widget(b)
+    clock.drive(b, DT, n=int((b.pause_start_sec + max_offset_of(b) / b.pixels_per_second * 0.5) / DT))
+    assert a.scroll_offset == 0
+    assert b.scroll_offset > 0
+
+    panel.sel_widget(_plain_widget(panel, font))
+    clock.drive(a, DT, n=50)
+    clock.drive(b, DT, n=50)
+    assert offsets() == (0, 0)
+
+
+def _plain_widget(panel, font):
+    from uilib.text import TextWidget
+
+    w = TextWidget(box=Box.xywh(0, 100, 60, 36), text="plain", font=font, parent=panel)
+    panel.add_sel_widget(w)
+    return w