And now it's spinning ni the center. I don't know why x=100, y=100 is the center origin of a 100x100 square so more research needed.

sfmldemo/main.cpp

@@ -50,6 +50,7 @@ int main() {
   ImGui_setup(window);
 
   sf::CircleShape shape(100.f, 4);
+  shape.setOrigin(100.f, 100.f);
   shape.setFillColor(sf::Color(150, 50, 250));
   shape.setOutlineThickness(10.f);
   shape.setOutlineColor(sf::Color(250, 150, 100));