SYMPTOMS

When using Morovia PDF417 fonts in edit boxes in an Acrobat PDF fill-able form, extra spaces are inserted between two rows, rendering the barcodes created un-readable.
This issue does not appear when you create PDF documents through Acrobat Distiller, nor in other word-processing application such as Microsoft Word.

CAUSE

Morovia fonts have internal marks embedded to protect our copy rights. These marks are invisible for normal use. Unfortunately, one particular mark in the PDF417 fonts has an unusual height.
Applications are supposed to use the height value declared by the font. While this is the case for most word-processing applications and operating systems, some applications, such as Acrobat Form Designer, use another way to determine the line height. These applications enumerate the heights of all characters inside the font, and choose the maximum value as the line height.

SOLUTION

If you need to create PDF417 barcodes through a form field in a PDF document, download the font files attached in this article. Unzip the font files to a temporary folder. Navigate to the PDF417 installation folder c:\program files\morovia\pdf417fontware. Overwrite the original font files. Reboot your computer.

The version of the new fonts is 3.1, which can be verified in the font viewer.