[ft] FT_Set_Char_Size vs. FT_Set_Pixel_Sizes

[Olumide]

Dear List,

I am using FreeType not to render to screen but just to rasterize a font 
for some esoteric purpose that I won't bother to describe. That said 
should I be using FT_Set_Char_Size or FT_Set_Pixel_Sizes?

As I am not rendering to screen, dpi does not matter in the slightest bit.

Regards,

- Olumide