fix(patterns): correct non-blocking timing and blink off phase

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

src/patterns/bar_graph.py

@@ -16,7 +16,7 @@ class BarGraph:
                 target = (self.driver.num_leds * level) // 100
                 lit = self.driver.apply_brightness(colors[0], preset.b)
                 unlit = self.driver.apply_brightness(
-                    colors[1] if len(colors) > 1 else (0, 0, 0),
+                    colors[-1],
                     preset.b,
                 )
                 for i in range(self.driver.num_leds):

src/patterns/blink.py

@@ -25,7 +25,7 @@ class Blink:
                     # Advance to next color for the next "on" phase
                     color_index += 1
                 else:
-                    # "Off" phase: turn all LEDs off
+                    # "Off" phase should actually be off.
                     self.driver.fill((0, 0, 0))
                 state = not state
                 last_update = utime.ticks_add(last_update, delay_ms)

src/patterns/chase.py

@@ -26,6 +26,7 @@ class Chase:
 
         color0 = self.driver.apply_brightness(color0, preset.b)
         color1 = self.driver.apply_brightness(color1, preset.b)
+        bg_color = self.driver.apply_brightness(colors[-1], preset.b)
 
         n1 = max(1, int(preset.n1))  # LEDs of color 0
         n2 = max(1, int(preset.n2))  # LEDs of color 1
@@ -53,7 +54,7 @@ class Chase:
         # If auto is False, run a single step and then stop
         if not preset.a:
             # Clear all LEDs
-            self.driver.n.fill((0, 0, 0))
+            self.driver.n.fill(bg_color)
 
             # Draw repeating pattern starting at position
             for i in range(self.driver.num_leds):
@@ -98,7 +99,7 @@ class Chase:
                     position += max_pos
 
                 # Clear all LEDs
-                self.driver.n.fill((0, 0, 0))
+                self.driver.n.fill(bg_color)
 
                 # Draw repeating pattern starting at position
                 for i in range(self.driver.num_leds):

src/patterns/circle.py

@@ -31,10 +31,10 @@ class Circle:
             base0 = base1 = (255, 255, 255)
         elif len(colors) == 1:
             base0 = colors[0]
-            base1 = (0, 0, 0)
+            base1 = colors[-1]
         else:
             base0 = colors[0]
-            base1 = colors[1]
+            base1 = colors[-1]
 
         color0 = self.driver.apply_brightness(base0, preset.b)
         color1 = self.driver.apply_brightness(base1, preset.b)
@@ -46,7 +46,7 @@ class Circle:
             if phase == "off":
                 self.driver.n.fill(color1)
             else:
-                self.driver.n.fill((0, 0, 0))
+                self.driver.n.fill(color1)
 
             # Calculate segment length
             segment_length = (head - tail) % self.driver.num_leds

src/patterns/clock_sweep.py

@@ -15,7 +15,7 @@ class ClockSweep:
             d = max(1, int(preset.d))
             now = utime.ticks_ms()
             if utime.ticks_diff(now, last) >= d:
-                bg = self.driver.apply_brightness(colors[1] if len(colors) > 1 else (0, 0, 0), preset.b)
+                bg = self.driver.apply_brightness(colors[-1], preset.b)
                 fg = self.driver.apply_brightness(colors[0], preset.b)
                 for i in range(self.driver.num_leds):
                     self.driver.n[i] = bg

src/patterns/comet_dual.py

@@ -17,8 +17,9 @@ class CometDual:
             d = max(1, int(preset.d))
             now = utime.ticks_ms()
             if utime.ticks_diff(now, last) >= d:
+                bg_color = self.driver.apply_brightness(colors[-1], preset.b)
                 for i in range(self.driver.num_leds):
-                    self.driver.n[i] = (0, 0, 0)
+                    self.driver.n[i] = bg_color
                 c1 = self.driver.apply_brightness(colors[0 % len(colors)], preset.b)
                 c2 = self.driver.apply_brightness(colors[1 % len(colors)] if len(colors) > 1 else colors[0], preset.b)
                 for t in range(tail):

src/patterns/fireflies.py

@@ -16,8 +16,9 @@ class Fireflies:
             d = max(1, int(preset.d))
             now = utime.ticks_ms()
             if utime.ticks_diff(now, last) >= d:
+                bg_color = self.driver.apply_brightness(colors[-1], preset.b)
                 for i in range(self.driver.num_leds):
-                    self.driver.n[i] = (0, 0, 0)
+                    self.driver.n[i] = bg_color
                 for b in bugs:
                     idx, ph = b
                     tri = 255 - abs(128 - ph) * 2

src/patterns/heartbeat.py

@@ -9,22 +9,28 @@ class Heartbeat:
         colors = preset.c if preset.c else [(255, 0, 40)]
         phase = 0
         phase_start = utime.ticks_ms()
-        lit_color = self.driver.apply_brightness(colors[0], preset.b)
+        did_manual_pulse = False
         while True:
             p1 = max(20, int(preset.n1) if int(preset.n1) > 0 else 120)
             p2 = max(20, int(preset.n2) if int(preset.n2) > 0 else 80)
             pause = max(20, int(preset.n3) if int(preset.n3) > 0 else 500)
             beat_gap = max(20, int(preset.d))
+            colors = preset.c if preset.c else [(255, 0, 40)]
             lit_color = self.driver.apply_brightness(colors[0], preset.b)
+            bg_color = self.driver.apply_brightness(colors[-1], preset.b)
             phase_durations = (p1, beat_gap, p2, pause)
-            phase_colors = (lit_color, (0, 0, 0), lit_color, (0, 0, 0))
+            phase_colors = (lit_color, bg_color, lit_color, bg_color)
 
             now = utime.ticks_ms()
-            if utime.ticks_diff(now, phase_start) >= phase_durations[phase]:
+            while utime.ticks_diff(now, phase_start) >= phase_durations[phase]:
+                phase_start = utime.ticks_add(phase_start, phase_durations[phase])
                 phase = (phase + 1) % 4
-                phase_start = utime.ticks_add(phase_start, phase_durations[(phase - 1) % 4])
 
             self.driver.fill(phase_colors[phase])
             yield
-            if not preset.a and phase == 0:
+            if not preset.a:
+                if did_manual_pulse or phase == 0:
+                    self.driver.fill(bg_color)
+                    yield
                     return
+                did_manual_pulse = True

src/patterns/marquee.py

@@ -17,9 +17,10 @@ class Marquee:
             now = utime.ticks_ms()
             if utime.ticks_diff(now, last) >= d:
                 c = self.driver.apply_brightness(colors[0], preset.b)
+                bg_color = self.driver.apply_brightness(colors[-1], preset.b)
                 for i in range(self.driver.num_leds):
                     m = (i + phase) % (on_len + off_len)
-                    self.driver.n[i] = c if m < on_len else (0, 0, 0)
+                    self.driver.n[i] = c if m < on_len else bg_color
                 self.driver.n.write()
                 phase = (phase + step) % (on_len + off_len)
                 self.driver.step = phase

src/patterns/orbit.py

@@ -15,8 +15,9 @@ class Orbit:
             d = max(1, int(preset.d))
             now = utime.ticks_ms()
             if utime.ticks_diff(now, last) >= d:
+                bg_color = self.driver.apply_brightness(colors[-1], preset.b)
                 for i in range(self.driver.num_leds):
-                    self.driver.n[i] = (0, 0, 0)
+                    self.driver.n[i] = bg_color
                 for k in range(orbits):
                     idx = ((phase * (k + 1)) // 8 + (k * self.driver.num_leds // max(1, orbits))) % max(1, self.driver.num_leds)
                     self.driver.n[idx] = self.driver.apply_brightness(colors[k % len(colors)], preset.b)

src/patterns/pulse.py

@@ -18,6 +18,7 @@ class Pulse:
 
         # State machine based pulse using a single generator loop
         while True:
+            bg_color = self.driver.apply_brightness(colors[-1], preset.b)
             # Read current timing parameters from preset
             attack_ms = max(0, int(preset.n1))  # Attack time in ms
             hold_ms = max(0, int(preset.n2))    # Hold time in ms
@@ -49,7 +50,7 @@ class Pulse:
                 self.driver.fill(self.driver.apply_brightness(color, preset.b))
             elif elapsed < total_ms:
                 # Delay phase: LEDs off between pulses
-                self.driver.fill((0, 0, 0))
+                self.driver.fill(bg_color)
             else:
                 # End of cycle, move to next color and restart timing
                 color_index += 1

src/patterns/radiate.py

@@ -17,7 +17,7 @@ class Radiate:
         """
         colors = preset.c if preset.c else [(255, 255, 255)]
         base_on = colors[0]
-        base_off = colors[1] if len(colors) > 1 else (0, 0, 0)
+        base_off = colors[-1]
 
         spacing = max(1, int(preset.n1))
         outward_ms = max(1, int(preset.n2))

src/patterns/rain_drops.py

@@ -16,8 +16,9 @@ class RainDrops:
             d = max(1, int(preset.d))
             now = utime.ticks_ms()
             if utime.ticks_diff(now, last) >= d:
+                bg_color = self.driver.apply_brightness(colors[-1], preset.b)
                 for i in range(self.driver.num_leds):
-                    self.driver.n[i] = (0, 0, 0)
+                    self.driver.n[i] = bg_color
                 if random.randint(0, 255) < rate:
                     drops.append([random.randint(0, max(0, self.driver.num_leds - 1)), 0])
                 nd = []

src/patterns/scanner.py

@@ -27,12 +27,13 @@ class Scanner:
             if utime.ticks_diff(now, last_update) >= delay_ms:
                 base = colors[color_index % len(colors)]
                 base = self.driver.apply_brightness(base, preset.b)
+                bg_color = self.driver.apply_brightness(colors[-1], preset.b)
                 for i in range(self.driver.num_leds):
                     dist = i - center
                     if dist < 0:
                         dist = -dist
                     if dist > width:
-                        self.driver.n[i] = (0, 0, 0)
+                        self.driver.n[i] = bg_color
                     else:
                         scale = ((width - dist) * 255) // max(1, width)
                         self.driver.n[i] = (

src/patterns/segment_chase.py

@@ -24,13 +24,14 @@ class SegmentChase:
             d = max(1, int(preset.d))
             now = utime.ticks_ms()
             if utime.ticks_diff(now, last) >= d:
+                bg_color = self.driver.apply_brightness(colors[-1], preset.b)
                 for i in range(self.driver.num_leds):
                     seg_idx = i // seg
                     in_seg = i % seg
                     local_phase = (phase + seg_idx * seg_offset) % seg
                     lit_idx = (in_seg + local_phase) % seg
                     if gap > 0 and lit_idx >= max(1, seg - gap):
-                        self.driver.n[i] = (0, 0, 0)
+                        self.driver.n[i] = bg_color
                     else:
                         color_idx = seg_idx % len(colors)
                         self.driver.n[i] = self.driver.apply_brightness(colors[color_idx], preset.b)

src/patterns/snowfall.py

@@ -16,10 +16,11 @@ class Snowfall:
             d = max(1, int(preset.d))
             now = utime.ticks_ms()
             if utime.ticks_diff(now, last) >= d:
+                bg_color = self.driver.apply_brightness(colors[-1], preset.b)
                 if random.randint(0, 255) < density:
                     flakes.append([self.driver.num_leds - 1, random.randint(0, len(colors)-1)])
                 for i in range(self.driver.num_leds):
-                    self.driver.n[i] = (0, 0, 0)
+                    self.driver.n[i] = bg_color
                 nf = []
                 for pos, ci in flakes:
                     if 0 <= pos < self.driver.num_leds:

src/patterns/strobe_burst.py

@@ -16,6 +16,7 @@ class StrobeBurst:
             cooldown = max(1, int(preset.n3) if int(preset.n3) > 0 else 400)
             on_ms = max(1, int(preset.d) // 2)
             c = self.driver.apply_brightness(colors[0], preset.b)
+            bg_color = self.driver.apply_brightness(colors[-1], preset.b)
             now = utime.ticks_ms()
 
             if state == "flash_on":
@@ -24,7 +25,7 @@ class StrobeBurst:
                     state = "flash_off"
                     state_start = utime.ticks_add(state_start, on_ms)
             elif state == "flash_off":
-                self.driver.fill((0, 0, 0))
+                self.driver.fill(bg_color)
                 if utime.ticks_diff(now, state_start) >= gap:
                     flash_idx += 1
                     if flash_idx >= count:
@@ -37,7 +38,7 @@ class StrobeBurst:
                         state = "flash_on"
                         state_start = utime.ticks_add(state_start, gap)
             else:
-                self.driver.fill((0, 0, 0))
+                self.driver.fill(bg_color)
                 if utime.ticks_diff(now, state_start) >= cooldown:
                     state = "flash_on"
                     state_start = utime.ticks_add(state_start, cooldown)

src/patterns/twinkle.py

@@ -39,6 +39,7 @@ class Twinkle:
         """Twinkle: n1 activity, n2 density; n3/n4 min/max length of adjacent on/off runs."""
         palette = self._palette(preset)
         num = self.driver.num_leds
+        bg_color = self.driver.apply_brightness(palette[-1], preset.b)
         if num <= 0:
             while True:
                 yield
@@ -125,7 +126,7 @@ class Twinkle:
                     base = palette[colour_i[i] % len(palette)]
                     self.driver.n[i] = self.driver.apply_brightness(base, preset.b)
                 else:
-                    self.driver.n[i] = (0, 0, 0)
+                    self.driver.n[i] = bg_color
             self.driver.n.write()
             yield
             return
@@ -185,7 +186,7 @@ class Twinkle:
                         base = palette[next_ci[i] % len(palette)]
                         self.driver.n[i] = self.driver.apply_brightness(base, preset.b)
                     else:
-                        self.driver.n[i] = (0, 0, 0)
+                        self.driver.n[i] = bg_color
                 self.driver.n.write()
                 on = next_on
                 colour_i = next_ci

tests/all.py

@@ -184,6 +184,36 @@ def test_pattern_smoke():
         ctx.tick_for_ms(120)
 
 
+def test_patterns_do_not_use_blocking_sleep():
+    pattern_dir = "patterns"
+    offenders = []
+    try:
+        files = os.listdir(pattern_dir)
+    except OSError:
+        raise AssertionError("patterns directory is missing")
+
+    for filename in files:
+        if not filename.endswith(".py") or filename in ("__init__.py", "main.py"):
+            continue
+        path = pattern_dir + "/" + filename
+        try:
+            with open(path, "r") as f:
+                src = f.read()
+        except OSError:
+            offenders.append(filename + " (unreadable)")
+            continue
+
+        if (
+            "utime.sleep(" in src
+            or "utime.sleep_ms(" in src
+            or "time.sleep(" in src
+            or "time.sleep_ms(" in src
+        ):
+            offenders.append(filename)
+
+    assert not offenders, "blocking sleep found in patterns: %s" % ", ".join(offenders)
+
+
 def test_default_requires_existing_preset():
     ctx = _TestContext()
     _process_message(ctx, {"v": "1", "default": "missing"})
@@ -242,6 +272,7 @@ def run_all():
         test_preset_edit_sanitization,
         test_colour_conversion_and_transition,
         test_pattern_smoke,
+        test_patterns_do_not_use_blocking_sleep,
         test_default_requires_existing_preset,
         test_default_targets_gate_by_device_name,
         test_save_and_load_roundtrip,