Direct3D is a high-performance, COM-based API for accessing graphics hardware (GPUs) in a device-independent way on Microsoft platforms.
Graphics Device Interface (GDI) is a device-independent, pure software graphics API under the Windows operating system for drawing graphic primitives and text
Imho the right way to go is direct3d or opengl but given delphi is windows only maybe direct3d is better;delphi was introduced exactly because the gdi is not good at such tasks
Delphi 6: Can native Delphi do smooth graphics like Flash?
So decide what you want to use direct3d is significaly faster than gdi
Should I use Direct3D or just Windows GDI for a fancy/high-perf Win32 app UI?