Printer controller having JPEG and EDRL circuitry

1. A printer controller in a printer comprising:

page data input circuitry for receiving compressed and encoded page data for expansion processing;

JPEG decoding circuitry for decompressing contone data in the received page data;

Edge data and runlength (EDRL) expansion circuitry for decompressing EDRL-compressed bi-level image data in the received page data;

halftoning and compositing circuitry for halftoning and compositing the decompressed contone and bi-level data; and

a printhead interface for receiving the compositing data and for writing corresponding print data to a printhead of the printer,

wherein the edge data and runlength (EDRL) expansion circuitry is configured to generate sets of bi-level image lines that are scaled horizontally from a resolution of an expanded bi-level image by a suitable scale factor to a print resolution from a bi-level image data EDRL-compressed by coding an edge in a line relative to a previous edge in the same line comprising decoding its runlength from the previous edge in the same line to a string of one bits or zero bits representing a corresponding part of the image.

2. A printer controller as claimed in claim 1 , wherein the circuitry and interface are interconnected by a bus.

3. A printer controller as claimed in claim 2 , wherein the bus is a processor address, data and control bus.

4. A printer controller as claimed in claim 1 , in which the JPEG decoding circuitry is configured to receive an input in the form of a JPEG bitstream and to generate an output in the form of a set of contone image lines.

5. A printer controller as claimed in claim 1 which includes DMA controller circuitry for controlling data transfer between the circuitry and interface.