OpenPrinterVirtual Printer
Test protocol delivery and rendering without physical printer hardware.
A virtual printer emulates a concrete printer class. It captures the data at the same boundary used by a real printer backend, then shows a preview of the result. It does not call a platform driver or require printer hardware.
Use it to:
- develop an integrating server without printer hardware
- exercise actual ESC/POS rendering and interpretation
- preview the same page raster sent toward an office printer driver
- test restart recovery and idempotency
- simulate predictable failures
Virtual printer profiles
| Profile | Input and preview |
|---|---|
| Virtual Thermal 58 mm or 80 mm | OPPA renders ESC/POS, then the virtual device interprets those bytes into a receipt preview. |
| Virtual Office A4 | OPPA renders a page raster, then the virtual device captures that page for preview. |
Thermal diagnostics summarize command count, interpreted text, images, QR codes, barcodes, feed, cut, and unsupported commands. Unsupported commands stop interpretation; arbitrary trailing bytes are not treated as text. Cut is kept as device metadata and does not add visible content to an office page.
Simulation modes
| Mode | Behavior |
|---|---|
| Always succeed | Captures output and returns a submission receipt |
| Fail next job | Fails once, then returns to success |
| Always fail | Returns a structured simulated failure |
| Delay submission | Waits for the configured bounded delay |
| Offline | Reports that the printer is unavailable |
The virtual printer never reports physical completion. A successful simulation produces the same submitted state used by other spoolers.
Local history
Captured page images and bounded diagnostics are stored as development-oriented local history. The UI can inspect or clear them. The history view does not display raw ESC/POS bytes by default.
Automated tests
Automated tests cover both profiles, the supported ESC/POS command subset, and ESC/POS-to-office-page compatibility. Agent lifecycle tests also verify the required order: persistence, receipt acknowledgement, rendering, submission, result persistence, and result reporting. CI does not need platform printer drivers.