Change fixed colors to animated colors

modules/Polygon/Polygon.cpp

@@ -30,6 +30,7 @@ private:
     Color _stroke_color {"#FFFFFF"};
     Color _fill_color {"#606060"};
     std::vector<Point> _points;
+    double _hue;
 };
 
 ScreensaverPlugin *create_instance() { return new Polygon; }
@@ -39,8 +40,6 @@ void Polygon::configure() {
     _min_speed = _j["min-speed"];
     _max_speed = _j["max-speed"];
     _stroke_width = _j["stroke-width"];
-    _stroke_color = _j["stroke-color"];
-    _fill_color = _j["fill-color"];
     for (int i = 0; i < _num_points; ++i) {
         Point p;
         p.x = random_x();
@@ -51,6 +50,7 @@ void Polygon::configure() {
         p.speed_y *= random_bool() ? 1 : -1;
         _points.push_back(p);
     }
+    _hue = random_between(0.0, 360.0);
 }
 
 void Polygon::size_changed() {
@@ -63,6 +63,7 @@ void Polygon::size_changed() {
 std::string Polygon::version() const { return "1.0.0"; }
 
 void Polygon::update() {
+    // update points
     for (Point& p : _points) {
         p.x += p.speed_x;
         if (p.x < 0 || p.x > _r.width) {
@@ -75,6 +76,19 @@ void Polygon::update() {
             p.y += p.speed_y;
         }
     }
+    // update hue
+    _hue += 0.5;
+    if (_hue >= 360.0) {
+        _hue -= 360.0;
+    }
+    // construct stroke and fill colors
+    HSB hsb;
+    hsb.h = _hue;
+    hsb.s = 1.0;
+    hsb.b = 0.1;
+    _fill_color = hsb;
+    hsb.b = 0.7;
+    _stroke_color = hsb;
 }
 
 void Polygon::render() {