Screenshot : http://caladan.rave.org/magnifier.png

This is a layout modifier that will make a layout increase the size of the window that has focus.

You can use this module with the following in your ~/.xmonad/xmonad.hs:

 import XMonad.Layout.Magnifier

Then edit your layoutHook by adding the magnifier layout modifier to some layout:

 myLayouts = magnifier (Tall 1 (3/100) (1/2))  ||| Full ||| etc..
 main = xmonad defaultConfig { layoutHook = myLayouts }

By default magnifier increases the focused window's size by 1.5. You can also use:

 magnifiercz (12%10)

to use a custom level of magnification. You can even make the focused window smaller for a pop in effect. Keep in mind, you must

 import Data.Ratio

in order to use rationals (such as 12%10) in your config.

For more detailed instructions on editing the layoutHook see:

XMonad.Doc.Extending#Editing_the_layout_hook

Magnifier supports some commands. To use them add something like this to your key bindings:

    , ((modMask x .|. controlMask              , xK_plus ), sendMessage MagnifyMore)
    , ((modMask x .|. controlMask              , xK_minus), sendMessage MagnifyLess)
    , ((modMask x .|. controlMask              , xK_o    ), sendMessage ToggleOff  )
    , ((modMask x .|. controlMask .|. shiftMask, xK_o    ), sendMessage ToggleOn   )

For detailed instruction on editing the key binding see XMonad.Doc.Extending#Editing_key_bindings.