Merge pull request #12 from kattni/neopixel-demo-code

Add toggle demo.

Author: dhalbert

examples/trellism4_neopixel_toggle.py

@@ -0,0 +1,45 @@
+import adafruit_trellism4
+
+trellis = adafruit_trellism4.TrellisM4Express()
+
+
+def wheel(pos):
+    if pos < 0 or pos > 255:
+        return 0, 0, 0
+    if pos < 85:
+        return int(255 - pos * 3), int(pos * 3), 0
+    if pos < 170:
+        pos -= 85
+        return 0, int(255 - pos * 3), int(pos * 3)
+    pos -= 170
+    return int(pos * 3), 0, int(255 - (pos * 3))
+
+
+led_on = []
+
+for x in range(trellis.pixels.width):
+    led_on.append([])
+    for y in range(trellis.pixels.height):
+        led_on[x].append(False)
+
+trellis.pixels.fill((0, 0, 0))
+
+current_press = set()
+
+while True:
+    pressed = set(trellis.pressed_keys)
+
+    for press in pressed - current_press:
+        x, y = press
+        if not led_on[x][y]:
+            print("Turning on:", press)
+            pixel_index = ((x + (y * 8)) * 256 // 32)
+            trellis.pixels[x, y] = wheel(pixel_index & 255)
+            led_on[x][y] = True
+
+        else:
+            print("Turning off:", press)
+            trellis.pixels[x, y] = (0, 0, 0)
+            led_on[x][y] = False
+
+    current_press = pressed