Blink animation for flowing one direction into another Blink

FlowToFace.ino

/*
 * Animation Sketch
 * Directional flow towards one side of a Blink
 * 
 */

Timer aniTimer;

#define ANI_DURATION 2000

void setup() {
  // put your setup code here, to run once:

}

void loop() {
  // put your main code here, to run repeatedly:
  if (buttonPressed()) {
    aniTimer.set(ANI_DURATION);
  }

  if (!aniTimer.isExpired()) {
    FOREACH_FACE(f) {
      byte val = getFaceValueForSendAnimation(0, f, ANI_DURATION, aniTimer.getRemaining(), 0, 255);
      setFaceColor(f, dim(ORANGE, val));
    }
  }
}

byte getFaceValueForSendAnimation(byte actionFace, byte f, long duration, long progress, byte low, byte high) {
  long offset = duration  / 6;
  byte dist = (actionFace + 6 - f) % 6;
  byte phase;
  switch (dist) {
    case 0: phase = 0; break;
    case 1: phase = 1; break;
    case 2: phase = 2; break;
    case 3: phase = 3; break;
    case 4: phase = 2; break;
    case 5: phase = 1; break;
  }
  long t0 = (phase * offset) + (duration - (offset * 3));
  long t1 = (phase * offset);
  byte value = map_m(progress, t0, t1, high, low);
  if (progress > t0) value = high;
  if (progress < t1) value = low;
  return value;
}

/*
  This map() functuion is now in Arduino.h in /dev
  It is replicated here so this skect can compile on older API commits
*/

long map_m(long x, long in_min, long in_max, long out_min, long out_max)
{
  return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
}