An article of manufacture comprising non-transitory data storage storing computer-readable instructions that, when executed by a processor having N (N is an integer equal to or more than 2) cores of a data processing device, causes the data processing device to perform tasks comprising:
- searching a new character as a character whose raster data is not stored in the memory among a plurality of characters specified by character data included in print data to count a count of the searched new characters;
- generating M (M being an integer equal to or less than the N) threads, the M being a count determined based on the count of the counted new characters among the N;
- dividing and allocating the plurality of characters to the M threads to generate raster data for the new characters using any one of the N cores for each of the M threads;
- and
- rendering the plurality of characters using raster data corresponding to the character data.