fix(presets): phase-lock blink and one tick on re-select

Co-authored-by: Cursor <cursoragent@cursor.com>

src/presets.py

@@ -201,16 +201,13 @@ class Presets:
                     self.fill((0, 0, 0))
                     self.selected = preset_name
                     return True
-                # Manual single-shot patterns: if this select arrives before the main loop has
+                # If re-selecting the same preset before the main loop has tick()'d the
-                # tick()'d the previous frame, completing it first keeps step in sync with beats.
+                # previous frame, run one pending tick so step stays in sync.
                 if (
                     preset_name == self.selected
-                    and not preset.a
-                    and preset.p in ("chase", "pulse")
                     and self.generator is not None
                 ):
-                    while self.generator is not None:
+                    self.tick()
-                        self.tick()
                 # Set step value if explicitly provided
                 if step is not None:
                     self.step = step
@@ -274,11 +271,22 @@ class Presets:
         colors = preset.c if preset.c else [(255, 255, 255)]
         bg_color = self.apply_brightness(preset.background_or(colors), preset.b)
         color_index = 0
-        state = True
+        delay_ms = max(1, int(preset.d))
-        last_update = utime.ticks_ms()
+        period = delay_ms * 2
+        now = utime.ticks_ms()
+        # Phase-lock to wall time so group identify (broadcast select) stays in sync even
+        # when devices process the packet on different main-loop iterations.
+        phase = now % period if period else 0
+        state = phase < delay_ms
+        last_update = utime.ticks_add(now, -phase)
+        if state:
+            base = colors[color_index % len(colors)]
+            self.fill(self.apply_brightness(base, preset.b))
+            color_index += 1
+        else:
+            self.fill(bg_color)
         while True:
             now = utime.ticks_ms()
-            delay_ms = max(1, int(preset.d))
             if utime.ticks_diff(now, last_update) >= delay_ms:
                 if state:
                     base = colors[color_index % len(colors)]