In Zend_Barcode_Object_Code128 when adding entries to the $barcodeTable in _prepareBarcode all entries are added with a width of 1 pixel instead of respecting the barThinWidth option.

This results in barcodes being output where the bars fill only a fraction of the available width.

It's worth noting that _calculateBarcodeWidth does respect this option correctly.

$barcodeTable[] = array($c, 1, 0, 1);

$barcodeTable[] = array($c, $this->_barThinWidth, 0, 1);

As a workaround the scaling factor option may be provided instead so long as the barThinWidth is left at 1. This is not ideal however and does of course impact other sizing calculations.