How can I map xrandr's scale function to keyboard shortcuts?

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http://unix.stackexchange.com – xrandr has a nifty feature that lets you scale your entire screen so that your virtual resolution is larger or smaller than your actual resolution. I use it on my netbook's 1024x600 resolution screen to work in a 1280x750 resolution workspace. Can I set up keyboard shortcuts to increase/decrease/reset the scale factor I'm currently using? Some applications do great with the extra space, while some are harder to read. I know how to set up keyboard shortcuts in my distribution already, but I don't know how I can make xrandr accept this sort of differential input (HowTos)