Image Processing Apparatus and Image Processing Program for Superimposing an Image

An image forming apparatus for printing a synthesized image in which an auxiliary image is superimposed on a normal image, comprising:

• an image processing unit comprising a renderer which generates normal image data comprising color information and image attribute information correspondent to pixels bitmap-expanded from said normal image based on normal image print data described in a predetermined print language, and an image data synthesizing unit to which auxiliary image data comprising at least color information correspondent to pixels bitmap-expanded from said auxiliary image and said normal image data are supplied, and which generates synthesized image data for each pixel by synthesizing pixel data of said normal image data and pixel data of said auxiliary image data;
• and
• a print engine which prints images based on said synthesized image data generated by said image processing unit.

An image processing program for generating a synthesized image in which an auxiliary image is superimposed on a normal image,

• the program causing a computer to configure an image data synthesizing unit to which normal image data comprising color information and image attribute information correspondent to pixels bitmap-expanded from said normal image and auxiliary image data comprising at least color information correspondent to pixels bitmap-expanded from said auxiliary image are supplied, and which generates synthesized image data for each pixel by synthesizing pixel data of said normal image data and pixel data of said auxiliary image data based on said color information and image attribute information of said normal image data.