Version:            (using KDE 4.2.4)
Compiler:          gcc version 4.2.4 (Gentoo 4.2.4-r1 p1.1) 
OS:                Linux
Installed from:    Compiled From Sources

I was wondering whether it is feasible for kprinter (or whatever kde:4 kprinter is now called) to automatically set the paper tray to match the pagesize of the individual pages in a print job. For instance, suppose I produce a letter+envelope with lyx (or kword or oowriter) and click print. If I've configured my printer (e.g. my Phaser 8860) for Tray1 to be #10envelopes, Tray2 to be letterpaper and Tray3 to be legalpaper, it would be nice for the printer program to automatically print the letter from Tray2 on letter media and to print the envelope from Tray1 on #10envelope media. It would be more efficient to configure defaults for a particular printer and then simply click print once. 

The LaTeX package envlab has shows several examples of embedding postscript special commands to automatically switch the paper tray from letter to envelope. Of course, most programs don't allow the user to embed postscript special commands. And most users don't know postscript. (Although one can use "lpoptions -p printqueue -l" to find the printer option names, that doesn't really help in finding the correct postscript commands) Since KDE's printing subsystem already knows how to set a printer's options, it would seem better to just let kprinter find the size of an individual page (maybe postscript bounding box or something) and choose the default tray for that pagesize for a particular printer.