Implement Hackertours effect

animation.py

@@ -120,6 +120,7 @@ class TwoColor(Steady):
     def name(self):
         return str(self)
 
+
 class Caramelldansen(Steady):
     """
         by Max & Lightmoll (https://lght.ml)
@@ -233,9 +234,36 @@ class Chase(Steady):
         return "chase"
 
 
-class ChaseRandom(Animation):
+class Hackertours(Steady):
+    """
+    Base color yellow, with green wandering back and forth
+    """
+    def __init__(self, color, base=(255,255,0), looptime=2.0):
+        super(Hackertours, self).__init__(color)
+        self.looptime = looptime
+        self.base = base
+
+    def update(self, index, count):
+        # angle is the position of the highlight on a circle, range [0, 1]
+        angle = (time() / self.looptime + (index + 0.0) / count) % 1.0
+        # map 0->1, 0.5->0, 1->1 to convert from circle to cylon
+        angle = abs(angle * 2 - 1)
+        l = 1 - min(abs(angle - 1 / count) * .9, 1.0 / count) * count
+        return (
+            int(self.r * l + self.base[0] * (1-l)),
+            int(self.g * l + self.base[1] * (1-l)),
+            int(self.b * l + self.base[2] * (1-l)))
+
+    def __str__(self):
+        return f"{type(self).__name__}({self.r}, {self.g}, {self.b}, {self.looptime:.2f})"
+
+    def name(self):
+        return "hackertours"
+
+
+class ChaseRandom(Steady):
     def __init__(self, color, looptime=1.0):
-        super(Chase, self).__init__(color)
+        super(ChaseRandom, self).__init__(color)
         self.looptime = looptime
 
     def update(self, index, count):