Add Support for Manual Duplex Scanning on Single-Sided Scanners (e.g., Brother MFC-L2800DW)

[oe3jtb]

Currently, NAPS2 supports duplex scanners with automatic duplex feeders, but lacks a convenient way to scan the reverse sides of multi-page documents on scanners without duplex capability (such as the Brother MFC-L2800DW).

Applications like Adobe Acrobat offer a feature that, when scanning multi-page documents on single-sided scanners, prompts the user after scanning the front sides to manually flip the pages and scan the backsides ("Prompt for more pages"). This allows users to perform double-sided scanning even with simple single-feed scanners, without interrupting the workflow or performing multiple separate scans.

Proposed Implementation:

Add an option in the scan settings that can be enabled when the scanner does not support automatic duplex.
After scanning the front sides, prompt the user to flip the pages and reinsert them to scan the backsides.
Automatically append the scanned backsides to the fronts to create a continuous double-sided PDF.
Optionally, allow this feature to be enabled by default or prompted for each scan session.
Benefits:

Increased flexibility and user-friendliness for users with single-sided scanners.
Eliminates cumbersome workarounds and separate scanning steps.
Enhances NAPS2’s competitiveness compared to commercial software like Adobe Acrobat.
I look forward to feedback and support for implementing this feature!