That's a good question. You'll have to download the source for those calls to find out.
Graphics.cs this is only one version there are others
public void DrawString(String s, Font font, Brush brush,RectangleF layoutRectangle, StringFormat format)
{
if (brush == null)
throw new ArgumentNullException("brush");
if (s == null || s.Length == 0)
return;
if (font == null)
throw new ArgumentNullException("font");
GPRECTF grf = new GPRECTF(layoutRectangle);
IntPtr nativeStringFormat = (format == null) ? IntPtr.Zero : format.nativeFormat;
int status = SafeNativeMethods.Gdip.GdipDrawString(new HandleRef(this, this.NativeGraphics),s, s.Length, new HandleRef(font, font.NativeFont), ref grf, new HandleRef(format,nativeStringFormat), new HandleRef(brush, brush.NativeBrush));
CheckErrorStatus(status);
}
The other function I was not able to find so easily.
You can get the source from microsoft. There are instructions for using it in Visual Studio so that you can step through it.
Hope that helps.
Gregg