Inconsistent Code 93 scanning of low-resolution images (14 Comments)

Issue report by Jeremy Bante

Product

FileMaker Go

Version

13.0.2

Operating system version

iOS 7.0.4 (11B554a)

Description of the issue

FileMaker Go is sometimes unable to scan a Code 93 barcode from a low resolution image. Higher resolution images with identical bar patterns scan successfully. I suspected that the low resolution might be the problem, but other images with the same one-pixel-per-module resolution also scanned successfully.

Steps to reproduce the problem

Render a Code 93 barcode at a resolution of 1 pixel per module and insert it into a container field. Attempt to scan the barcode using the Insert from Device script step, scanning directly from the container field. (This does not fail with all symbols.) Render the exact same bar pattern at a higher resolution, and insert it into a container field. Scan the larger image using the Insert from Device script step.

Expected result

Scanning the lower resolution image should decode the Code 93 barcode every time.

Actual result

The lower resolution image is not always successfully scanned. In these cases, the target field of the Insert from Device script step is left blank. The Insert from Device script step results in error 418 ("Internal failure in INSERT operation into a field").

Exact text of any error message(s) that appear

If error capture is off when the Insert from Device script step is run, a dialog titled "Error" opens with the message "Insert from Device failed." and one button option labeled "OK".

Configuration information

Not all low resolution Code 93 barcodes have trouble being decoded. The larger barcodes that scan successfully have width dimensions that are exact integer-multiple widths of the smaller codes with identical bar patterns. I made a file demonstrating barcodes that do and do not demonstrate the bug: https://www.dropbox.com/s/43edn2kibhc2cb2/BugSampleCode93.fmp12.zip

Workaround

Rendering a larger version of the barcode reliably makes it scannable.