If I use the Barcode4j Code 128 with a module width of 1px and export it to an PNG, the barcode is not readable for a scan device. In the picture you can see Gray module areas. For an barcode height of 10px the module width must be set to 0.98, to have a clean barcode in the exported PNG.
That makes no sense, does it?
In the component.xsd the type for the field moduleWidth is defined as double. But I can't enter a double value in the Design Editor. Only integer values are allowed (1px, 2px, etc.). I have to go to the Source editor, find the barcode component and add the value of 0.98 there.
Please use my test report barcode4j_moduleWidth_issue.jrxml to reproduce the problem and have a look to the barcode4j_moduleWidth_issue.png to see how the result will looks like.