How To Use The Raster Feature In 3D2HOLO Desktop

What the raster feature does

Inside 3d2holo-desktop, raster mode is the output path used when you choose `FORMAT = ras`. Instead of saving a regular bitmap for a general editor, the app prepares a CUPS raster stream that is easier to hand off to a printer queue configured through CUPS.

The desktop code currently exposes raster-specific controls for resolution, raster direction, printer selection, page size, and X/Y placement offsets. When you print, the native addon submits the file through CUPS and explicitly passes print options such as `Resolution`, `PageSize`, `media`, and `StpPrintingDirection=Unidirectional`.

At the moment, raster mode directly supports only Epson L1800, Epson L1300, and Epson P608. If another Epson printer is supported by Gutenprint, you can still start by selecting Epson L1800 inside 3d2holo-desktop as a temporary fallback for testing.

• Use raster mode when the last step of your workflow is an actual CUPS-managed print process, not only a file handoff.
• Use it when you want the page size and physical placement to line up with printer settings before submitting a job.
• Use it when your Epson workflow depends on Gutenprint options inside a CUPS queue.

1. Install Gutenprint and CUPS for an Epson workflow

On Debian and Ubuntu based systems, the simplest path is to install CUPS plus the Gutenprint CUPS driver package. The package names below match the current package search on a Debian/Ubuntu style system.

1. Install `cups`, `cups-client`, and `cups-daemon` so the print service and queue tools are available.
2. Install `printer-driver-gutenprint` so Epson printers can expose Gutenprint-backed PPD and driver options in CUPS.
3. Start or enable the CUPS service, then open the CUPS web interface at `http://localhost:631`.

sudo apt update
sudo apt install cups cups-client cups-daemon printer-driver-gutenprint
sudo systemctl enable --now cups

After installation, verify that CUPS sees the queue and that Gutenprint-backed options are visible. The second command is especially useful because it lists the actual option names your queue exposes.

lpstat -p -d
lpoptions -p YOUR_PRINTER_NAME -l | rg 'Resolution|PageSize|media|Stp'

2. Configure the printer in CUPS

CUPS is where the queue, default media behavior, and driver-backed options are defined. A safe setup pattern is to add the printer first, print a plain test page, and only then move into raster output from 3d2holo-desktop.

1. Open `http://localhost:631`, go to `Administration`, and choose `Add Printer`.
2. Select your Epson printer, authenticate if asked, and choose the Gutenprint driver entry for the printer model.
3. After the queue is created, open the printer page and use `Set Default Options`.

For the actual queue defaults, follow the parameter values shown in the screenshots below. They reflect the intended CUPS setup for the current raster workflow more directly than a generic table.

3. Use raster mode inside 3d2holo-desktop

Once the printer queue is ready, the in-app workflow is straightforward. The raster controls appear only when the output format is switched to `ras`, and the print button is shown only after the exported file path ends with `.ras`.

1. Open the 2D, 3D, Sketchfab, or pitch-test workflow that will generate the image you want to print.
2. Set `FORMAT` to `ras` in the Output section.
3. Choose the `5760*2880` preset for `RESOLUTION`.
4. Set `DIRECTION` to the raster orientation you want for the print job. If you are testing a standard horizontal lenticular layout, start with `horizontal` and verify with a small print first.
5. Choose `PRINTER` and `SIZE` so the raster job targets the intended queue and paper format.
6. Adjust `X OFFSET (IN)` and `Y OFFSET (IN)` to position the printable content on the sheet. The layout preview in the desktop UI is there to help center or shift the raster rectangle before export.
7. Export the result. If the saved result is a `.ras` file, the desktop UI will expose the `Print` button for direct submission through CUPS.
8. Use the active job list in CUPS, or the app's print status, to confirm the job reached the queue.

Common problems to check first

• If the app says no printer is configured, make sure CUPS has either a default printer or the exact queue name selected in the raster printer field.
• If print placement looks wrong, confirm that the CUPS `PageSize` and the in-app `SIZE` really match the same paper definition.
• If the image scale looks wrong, verify that the raster resolution preset in the app matches the queue resolution exposed by Gutenprint.
• If media behavior is inconsistent, check the queue defaults in CUPS instead of assuming the app can override every Gutenprint media option.