GDI+ Zeichenfehler bei ARC

[DaCoda]

@Kas Ob,

Hi Kas, in this moment i have a full project with drawing on a TPaintBox.
Everything is ok, but i want to have AntiAliasing for the Lines. So i tried to make a changeover to GDI+
The Normal Lines (procedure DrawLine) is easy to chnage over.

but i'am struggeling on procedure DrawArc. The changeover is not working.
You can see it in the attached Source in the first Post.

For this moment i'am not ready to make it in 3D. I have to study first the Tutorials and so on...

But i need the Program now with functional GDI+ and i have no idea whats going wrong in the attached Test-App.

If the GDI+ Version works well, i will start to make 3D Stuff