Set export resolution with printing size and DPI
Some users have complained that they have to compute the output resolution themselves when they need a specific dot density for a specific paper size. Especially for people in metric countries, they have to convert metric dimensions to inch, then multiply by the DPI for width and height. This is especially usefull when dealing with third-party requests (clients or suppliers such as magazines, printers, and customers).
In addition, the dot density meta-data in the exported file is always 72 DPI (again, seems to give a rash to less-educated clients who were told they need 300 DPI to print), so it would be great to adapt it to the user input when the output resolution is computed from paper size and DPI.