Using configure method to build knots

modules/Whirling/Whirling.cpp

@@ -21,38 +21,10 @@ struct Lissajous {
     double line_width;
     cairo_rectangle_t frame;
 
-    Lissajous(double f0,
-              double f1,
-              double f2,
-              double f3,
-              double p0,
-              double p1,
-              double p2,
-              double p3,
-              int segments,
-              double shift);
-
     double calc_x(double phi) const;
     double calc_y(double phi) const;
 };
 
-Lissajous::Lissajous(double f0,
-                     double f1,
-                     double f2,
-                     double f3,
-                     double p0,
-                     double p1,
-                     double p2,
-                     double p3,
-                     int segments,
-                     double shift)
-{
-    f[0] = f0; f[1] = f1; f[2] = f2; f[3] = f3;
-    p[0] = p0; p[1] = p1; p[2] = p2; p[3] = p3;
-    steps = segments;
-    delta = shift;
-}
-
 double Lissajous::calc_x(double phi) const {
     return sin(f[0] * phi + p[0]) * cos(f[1] * phi + p[1]);
 }
@@ -63,12 +35,13 @@ double Lissajous::calc_y(double phi) const {
 
 class Whirling : public ScreensaverPlugin {
     public:
-        Whirling();
+        Whirling() = default;
         ~Whirling() = default;
 
         int fps() const override;
         void update() override;
         void render() override;
+        void configure() override;
 
     private:
         std::vector<Lissajous> knots;
@@ -80,17 +53,6 @@ ScreensaverPlugin* create_instance() {
     return new Whirling;
 }
 
-Whirling::Whirling() {
-    knots.emplace_back(9, 7, 5, 7,
-                       0, 0, 0, 0,
-                       1000,
-                       2 * M_PI / 360.0);
-    Lissajous& knot = knots.back();
-    knot.color = {1.0, 1.0, 1.0}; // white
-    knot.alpha = 1.0; // opaque
-    knot.line_width = 1.0;
-}
-
 int Whirling::fps() const {
     return 30;
 }
@@ -131,3 +93,23 @@ void Whirling::render_knot(const Lissajous& knot) {
     cairo_set_line_width(_c, knot.line_width);
     cairo_stroke(_c);
 }
+
+void Whirling::configure() {
+    for (const auto& obj : _j["knots"]) {
+        Lissajous knot;
+        for (int i = 0; i < 4; ++i) {
+            knot.f[i] = obj["f"][i];
+        }
+        for (int i = 0; i < 4; ++i) {
+            knot.p[i] = obj["p"][i];
+        }
+        knot.steps = obj["steps"];
+        knot.delta = obj["delta"];
+        knot.color.r = obj["r"];
+        knot.color.g = obj["g"];
+        knot.color.b = obj["b"];
+        knot.alpha = obj["a"];
+        knot.line_width = obj["line_width"];
+        knots.push_back(knot);
+    }
+}