The encoding must be preserved when converting text. PDF files do not need preprocessing, the nature of PDF is that the file brings all which is needed so that it can be printed. So they are simply passed through. The program offers an interactive mode where the user can choose the encoding with a preview, choose whether text should be preprocessed, and choose which program will be used to print the file. This interactive mode can be turned off by the user.
Text is shown with a text viewer, using the chosen encoding.
So he can turn off stuffing in fonts when a document cannot be printed due to lack of memory in the PostScript printer. Cancels print job. Does the job with the current settings. Settings can also be done by environment variables.