How To Add a Driver

This page provides an introduction to adding drivers to LPrint.

Files

Most drivers consist of two source files:

• "lprint-NAME.h": List of driver names, descriptions (usually the make and model), and IEEE-1284 device IDs.
• "lprint-NAME.c": The code for the driver, including this driver's callback.

where "NAME" is the base name of the driver such as "acme" for ACME printers or "apcl" for printers that support an ACME Page Control Language. This name will also be used as a prefix for driver name strings (also lowercase, for example "acme_4inch-300dpi") and for global functions (this time capitalized, for example "lprintAcme" or "lprintAPCL").

You'll reference the driver in the "lprint.h" header, from the driver callback in "lprint.c", and in the makefile for the LPrint software.

lprint-NAME.h

lprint-NAME.c

lprint.h Additions

Add a function called "lprintNAME" using the PAPPL pappl_pr_driver_cb_t interface, where "NAME" is the driver base name. The previous "Acme" and "APCL" examples would look like:

// Acme driver callback
extern bool	lprintAcme(pappl_system_t *system, const char *driver_name, const char *device_uri, const char *device_id, pappl_pr_driver_data_t *data, ipp_t **attrs, void *cbdata);

// APCL driver callback
extern bool	lprintAPCL(pappl_system_t *system, const char *driver_name, const char *device_uri, const char *device_id, pappl_pr_driver_data_t *data, ipp_t **attrs, void *cbdata);

lprint.c Additions

The driver_cb function handles calling the appropriate driver callback function.

  // Acme driver
  else if (!strncmp(driver_name, "acme_", 5))
    ret = lprintAcme(system, driver_name, device_uri, device_id, data, attrs, cbdata);

  // APCL driver
  else if (!strncmp(driver_name, "apcl_", 5))
    ret = lprintAPCL(system, driver_name, device_uri, device_id, data, attrs, cbdata);

Makefile/Makefile.in Additions

Add the "lprint-NAME.o" file to the list of OBJS files:

OBJS    = \
        lprint.o \
        lprint-NAME.o \
        lprint-brother.o \
        lprint-common.o \
        ...