Patent attributes
An image data processing apparatus processes previously halftoned data that has been halftoned so that a proportion of dot formation corresponding to gradation values of an image reaches a first dot generation rate, as image data representative of the image. The image data processing apparatus includes a re-halftone processing unit configured to carry out a re-halftone process by using an error diffusion technique based on first gradation values corresponding to ON-dots in the previously halftoned data, and an ON-dot gradation value setting unit configured to set second gradation values corresponding to the ON-dots in the re-halftone process using the error diffusion technique, such that the dot generation rate in the re-halftone process reaches a second dot generation rate different from the first dot generation rate.
