Is TDirect2DCanvas slow or am I doing something wrong?

Question

While looking for alternatives to replace GDI, I was trying to test Delphi\'s 2010 TDirect2DCanvas performance in Windows 7.

I tested it by drawing a huge polyl

Answer 1

Direct2D relies on the driver and hardware implementation, so you're bound to have performance oddities depending on the hardware and driver you're running on (same bag of issues as 3D rendering engines face).

For instance on the issue of rendering lines, you'll likely face some (hidden) underlying hardware buffer issues: on a given hardware+driver, when drawing a polyline, if the underlying datasize is below a certain threshold, the performance could be high, with full hardware acceleration. Above that threshold, you could be falling back to a partially software or unoptimized path, and performance will plummet. The threshold will depend on hardware, driver and brush/drawing options, can be there, or not.

These are the same issues as when rendering 2D or 3D via OpenGL or regular DirectX, if you stray outside of well trodden rendering paths, things aren't so rosy.

As far as rendering non-antialiased graphics goes, my advice would be to stick with GDI, the implementations are solid with widespread hardware support.

For antialiased graphics, GDI+, Graphics32, AGG, and by and large, software-only solutions are preferable IME whenever you have no control over the end-user hardware. Otherwise, prepare yourself for customer support issues.