3.1 Modifier Layers

A modifier layer is activated when a key is held and one or more key code modifiers like shift, control, option, alt, altGr, command, windows gui and/or super key are applied. New key codes can then be defined using a modifier + a default layer key, creating a modifier layer. Many applications can also detect the difference between a left and right modifier. That creates many more modifiers depending on your OS available modifiers.

Because many applications will use 1 or 2 modifiers for shortcuts, often modifier layers use 3 or more modifiers. The two most popular have a name like the Meh key which is the left control, (alt/option), shift and the Hyper Key which is left control, (alt/option), shift (command/windows).

Modifier layers are a great entry point for layers because they can be done with only software. My first layer used auto hotkeys that modified the left alt key into a hyper key. This allowed me to create a navigation layer by then redefining hyper j, i, k, l keys into arrow keys.