made animation smoother; cleaner code

skembo/Skembo.cpp

@@ -32,22 +32,28 @@ void Skembo::setup(cairo_t* context, const cairo_rectangle_t& rect) {
 }
 
 int Skembo::fps() const {
-    return 20;
+    return 40;
 }
 
 void Skembo::draw_frame() {
-    // std::uniform_real_distribution<double> dist {};
+    // next color
     HSB hsb;
     hsb.h = _hue;
-    hsb.s = 1;//dist(_eng);
+    hsb.s = 1.0;
-    hsb.b = 0.4;//dist(_eng);
+    hsb.b = 0.4;
+
+    // convert to rgb
     Color color {hsb};
     RGB rgb {RGB(color)};
+
+    // setup color, fill whole window
     cairo_set_source_rgb(_c, rgb.r, rgb.g, rgb.b);
     cairo_rectangle(_c, _r.x, _r.y, _r.width, _r.height);
     cairo_fill(_c);
-    _hue += 1.0;
+
+    // update for next frame
+    _hue += 0.5;
     if (_hue > 360.0) {
-        _hue = 0.0;
+        _hue -= 360.0;
     }
 }