Data commit

Task/Mandelbrot-set/Vala/mandelbrot-set.vala

@@ -0,0 +1,49 @@
+public class Example: Gtk.Application {
+  private Gtk.ApplicationWindow window;
+  private Gtk.DrawingArea drawing_area;
+  public Example() {
+    Object(application_id: "my.application", flags: ApplicationFlags.FLAGS_NONE);
+    this.activate.connect(() => {
+      window = new Gtk.ApplicationWindow(this);
+      drawing_area = new Gtk.DrawingArea();
+      drawing_area.set_draw_func(draw_mandelbrot);
+      window.set_child(drawing_area);
+      window.present();
+    });
+  }
+
+  private void draw_mandelbrot(Gtk.DrawingArea area, Cairo.Context cr, int width, int height) {
+    cr.set_source_rgb(0, 0, 0);
+    cr.paint();
+    int x0 = -1;
+    double x_increment = 2.47 / (float) width;
+    double y_increment = 2.24 / (float) height;
+    for (double x = -2.0; x < 0.47; x += x_increment, x0++) {
+      int y0 = -1;
+      for (double y = -1.12; y < 1.12; y += y_increment, y0++) {
+        double c_re = x;
+        double c_im = y;
+        double x_ = 0,
+        y_ = 0;
+        int iterations = 0;
+        int max_iterations = 50;
+        while (iterations < max_iterations && x_ * x_ + y_ * y_ <= 4.0) {
+          double x_new = x_ * x_ - y_ * y_ + c_re;
+          y_ = 2.0 * x_ * y_ + c_im;
+          x_ = x_new;
+          iterations++;
+        }
+        if (iterations < max_iterations) {
+          cr.set_source_rgb((float) iterations / (float) max_iterations, 0, 0);
+          cr.rectangle(x0, y0, 1, 1);
+          cr.fill();
+        }
+      }
+    }
+  }
+
+  public static int main(string[] argv) {
+    var app = new Example();
+    return app.run(argv);
+  }
+}