Changing font size in rxvt-unicode via keyboard shortcuts

[Jens Mueller]

Hi,

I'm using rxvt-unicode version v7.9 and I'd like to change the font size
by a key mapping. I read in the manpage that changing font size via
Shift and +/- from the keypad isn't supported yet. Anyway I don't have a
key pad either. Further it states that I could add a keyboard shortcut
for this purpose. I read

URxvt.keysym.M-C-1: command:\033]710;suxuseuro\007\033]711;suxuseuro\007
URxvt.keysym.M-C-2: command:\033]710;9x15bold\007\033]711;9x15bold\007

in the manpage. But I don't know the proper lines to increase the size
by one and decrease it. Is this even possible? Maybe someone can even
point me to an explanation to decipher those lines. Maybe I can write my
own, if I know how.

Kind regards,
Jens