I have a couple of apps where users stick to FPD2.6 and have laser printers. All of them are either HP 5 or 6, and some are OKI 400, all using the provided Fox driver for HP III. It works well most of the time (if you consider using Courier only can be taken under "well").

I have a slight problem. Sometimes, practically at random, it prints one line overlapped over the previous line. Most of the cases it's the line preceding a line where a horizontal line is drawn using hyphens or equal signs, but I can't take it as a rule. It happens once in ten or twenty pages. Maybe it's because I'm printing into a file and replacing some Epson codes (which were hardcoded into some reports) with appropriate PCL codes, and I replace the font sizes according to font attributes (i.e. if it finds chr(15), it emits a "18 cpi" instead, if it finds bold, it puts larger font and so on).

I've looked at the hex dump and the offending lines look quite normal, having appropriate coordinates before each bit of text, and ending with regular cr+lf. Could it be the PCL is recalculating column/line coordinates into pixels, and miscalculating sometimes? Did anybody have this before?