Function: text-scale-adjust

Adjust the height of the default face by INC.

INC may be passed as a numeric prefix argument.

The actual adjustment made depends on the final component of the
key-binding used to invoke the command, with all modifiers removed:

+, = Increase the default face height by one step
- Decrease the default face height by one step
0 Reset the default face height to the global default

When adjusting with `+' or `-', continue to read input events and
further adjust the face height as long as the input event read
(with all modifiers removed) is `+' or `-'.

When adjusting with `0', immediately finish.

Each step scales the height of the default face by the variable
`text-scale-mode-step' (a negative number of steps decreases the
height by the same amount). As a special case, an argument of 0
will remove any scaling currently active.

This command is a special-purpose wrapper around the
`text-scale-increase' command which makes repetition convenient
even when it is bound in a non-top-level keymap. For binding in
a top-level keymap, `text-scale-increase' or `text-scale-decrease' may be more appropriate. (fn INC)