SvgTestDoc

void Polymorph() {
    using namespace std;
        {
            Document doc;
            doc.Render(cout);
            cout << endl;
        } {
            Document doc;
            doc.Add(Circle().SetCenter({20, 20}).SetRadius(10));
            doc.Render(cout);
            cout << endl;
        } {
            Document doc;
            doc.Add(Circle().SetCenter({20, 20}).SetRadius(10));
            doc.Add(Text()
                            .SetFontFamily("Verdana"s)
                            .SetPosition({35, 20})
                            .SetOffset({0, 6})
                            .SetFontSize(12)
                            .SetFontWeight("bold"s)
                            .SetData("Hello C++"s));
            doc.Add(Polyline().AddPoint({20, 20}).AddPoint({10, 15}).AddPoint({0, 10}));
            doc.Render(cout);
            cout << endl;
        } {
            Document doc;
            doc.AddPtr(make_unique<Circle>(move(
                    Circle().SetCenter({20, 20}).SetRadius(10))));
            doc.AddPtr(make_unique<Text>(move(
                        Text()
                        .SetFontFamily("Verdana"s)
                        .SetPosition({35, 20})
                        .SetOffset({0, 6})
                        .SetFontSize(12)
                        .SetFontWeight("bold"s)
                        .SetData("Hello C++"s))));
            doc.AddPtr(make_unique<Polyline>(move(
                    Polyline().AddPoint({20, 20}).AddPoint({10, 15}).AddPoint({0, 10}))));
            doc.Render(cout);
        }
    }

<?xml version="1.0" encoding="UTF-8" ?>
<svg xmlns="http://www.w3.org/2000/svg" version="1.1">
</svg>
<?xml version="1.0" encoding="UTF-8" ?>
<svg xmlns="http://www.w3.org/2000/svg" version="1.1">
  <circle cx="20" cy="20" r="10" />
</svg>
<?xml version="1.0" encoding="UTF-8" ?>
<svg xmlns="http://www.w3.org/2000/svg" version="1.1">
  <circle cx="20" cy="20" r="10" />
  <text x="35" y="20" dx="0" dy="6" font-size="12" font-family="Verdana" font-weight="bold">Hello C++</text>
  <polyline points="20,20 10,15 0,10" />
</svg>
<?xml version="1.0" encoding="UTF-8" ?>
<svg xmlns="http://www.w3.org/2000/svg" version="1.1">
  <circle cx="20" cy="20" r="10" />
  <text x="35" y="20" dx="0" dy="6" font-size="12" font-family="Verdana" font-weight="bold">Hello C++</text>
  <polyline points="20,20 10,15 0,10" />
</svg>