How raspberryy/emulated_usb_printer works
This is a Raspberry Pi USB printer-gadget emulator: a host recognizes the Pi as a configured printer and sends print data, which the program captures as raw job files and can optionally convert with GhostPDL. Its command-line interface also reports or changes printer status. The README describes further downstream uses for captured reports, but those are possibilities rather than implemented product stages in the sampled source. The main source excerpt is partial, so uncertain internal wiring is omitted.
Main entry points: printer.c Capture Loop · printer_minimal.c Minimal Capture Variant · README.md Printer Identity
Components 10
USB Printer Device
- Printer Gadget Driver
- Printer Identity
README.md
Job Capture
- Capture Loop
printer.c - Raw Job Files
printer.c - Minimal Capture Variant
printer_minimal.c
Status and Conversion
- Command-Line Interface
printer.c - Status Control
printer.c - GhostPDL Conversion
printer.c
Other components
- Print Host
- GhostPDL
Connections 12
- Printer Identity → Printer Gadget Driver: configures
- Print Host → Printer Gadget Driver: sends print data
- Printer Gadget Driver → Capture Loop: provides data
- Command-Line Interface → Capture Loop: dispatches read
- Capture Loop → Status Control: checks status
- Capture Loop → Raw Job Files: writes jobs
- Capture Loop → GhostPDL Conversion: requests conversion
- GhostPDL Conversion → GhostPDL: runs converter
- Command-Line Interface → Status Control: dispatches status
- Status Control → Printer Gadget Driver: reads or sets status
- Minimal Capture Variant → Printer Gadget Driver: reads print data
- Minimal Capture Variant → Raw Job Files: writes jobs