You can call the GetDeviceCaps function and test the capability against the RASTERCAPS capability. Note that if the Device does support graphics, but does not support another raster capability such as "StretchDib", Windows will handle the call by using lower level graphic primitives to accomplish the task. Example:

if (GetDeviceCaps(Printer.Canvas.Handle, RASTERCAPS) and
   RC_NONE) = RC_NONE then
NoGraphics := True;
if (GetDeviceCaps(Printer.Canvas.Handle, RASTERCAPS) and
   RC_STRETCHDIB) = RC_STRETCHDIB then
DeviceDirectly SupportsStretchDIB := True else
WIndowsWillSimulateStretchDIB := True;