It is a subject to provide an information processing apparatus which makes it
easy to form program parts depending on individual installation of image output
apparatuses and which can suppress an increase in code amount of driver software.
The apparatus has program modules for processing quantized image information in
accordance with characteristics of an image output apparatus by different methods
and virtual switches provided in a program. The modules having the unified interface
are switched by the virtual switches in accordance with either a mode of using
which image output apparatus as a target and a mode of using which function of
the image output apparatus when the image is formed. The formed data is handed
to the image output apparatus through a spooler prepare for the OS.