Есть такой код

System::Drawing::Bitmap^ bitmap=gcnew System::Drawing::Bitmap(200,200);
this->GraphArea->Image=bitmap;
System::Drawing::Graphics^ temp=System::Drawing::Graphics::FromImage(bitmap);
System::Drawing::Pen^ peb=gcnew System::Drawing::Pen(System::Drawing::Color::DarkSlateGray,2.0);

temp->InterpolationMode=System::Drawing::Drawing2D::InterpolationMode::HighQualityBicubic;
cli::array<System::Drawing::PointF>^ arr=gcnew cli::array<System::Drawing::PointF>(5)
{
    System::Drawing::PointF(5,5),
    System::Drawing::PointF(10,40),
    System::Drawing::PointF(20,90),
    System::Drawing::PointF(70,60),
    System::Drawing::PointF(100,100)
};
temp->DrawCurve(pen,arr,1,5);
delete pen;
delete temp;

Всё отрисовывается, но не сглаживается. В чём ошибка?