Why does printer changes resolution? User, background, what?

I am runing a .bat file from a php using exec on a Windwos php server, where php is run using fast-cgi (and nginx). The command line to run this script is

  pclose(popen("start / ". $cmd, "r"));  

Where $cmd is somethign like "mybatfile.bat 45 1"

When I run the batch file manually it runs a python program to read a database, get hold of some data, and print a little report. And it all works 100% correctly.

When it is run from the web page, the report comes out, so I know the program is run. The code logs the parameters passed. I know that the call is correct.

When run from the server/web page the report appears on the same printer approx 20% l开发者_StackOverflow中文版arger that when run from the coammnd line.

The python script uses PyQt and opens the printer in native mode.

The code is

    self.printer = QPrinter()
    self.printer.setPrinterName(printer)
    self.printer.setPageSize(QPrinter.A5)
    self.printer.setOrientation(QPrinter.Portrait)
    self.painter = QPainter(self.printer)

Does anyone know why this happens - and what can I do to correct it?

O/S is windows 7 (64 bit) for developement and a Server version for production. Python 2.7 32 bit. QT version 4.

Thanks Ian

Cracked it! The user who is running the server has never logged in (naturally) so they have never changed their screen resolution from 90 dpi.

I on the other hand, have changed by screen resolution because I use large fonts. So when I ran the print it printed in 120 dpi. When the server ran it, it printed in 90 dpi.

Solution.

After opening the printer, read the actual resolution back, and compute a scale factor.

Use the scale factor for all layout and positioning - except font sizes in points which will be correct anyway.