Akela-MagicCombo

The MagicCombo extension provides a way to perform custom actions when a particular set of keys are held down together. The functionality assigned to these keys are not changed, and the custom action triggers as long as all keys within the set are pressed. The order in which they were pressed do not matter.

This can be used to tie complex actions to key chords.

Using the extension

To use the extension, we must include the header, create a dictionary, and configure the plugin to use it:

#include <Akela-MagicCombo.h>

static const Akela::MagicCombo::dictionary_t dictionary[] PROGMEM = {
  {R1C3 | R2C1 | R2C4 | R2C7, // left hand,
   R0C11 | R1C12 | R2C14      //right hand
  },
  {0, 0}
};

void setup (void) {
  MagicCombo.configure (dictionary);

  Keyboardio.setup (KEYMAP_SIZE);
  Keyboardio.use (&MagicCombo, NULL);
}

The dictionary must reside in PROGMEM, and is a list of tuples. Each element in the array has two fields: the left hand state, and the right hand state upon which to trigger the custom action. Both of these are bit fields, each bit set tells the extension that the key with that index must be held for the action to trigger. It is recommended to use the RxCy macros of the core KeyboardioFirmware, and or them together to form a bitfield.

The dictionary must end with an element containing zero values for both the left and the right halves.

Extension methods

The extension provides a MagicCombo singleton object, with the following method:

.configure(dictionary)

Configures the extension to use the supplied dictionary.

.minInterval

Restrict the magic action to fire at most once every minInterval milliseconds.

Defaults to 500.

Not strictly a method, it is a variable one can assign a new value to.

Overrideable methods

Whenever an combination is found to be held, the extension will trigger an action, in each scan cycle until the keys remain held. This is done by calling the overrideable magicComboActions function:

magicComboActions(comboIndex, leftHand, rightHand)

Called whenever a combination is found to be held. The function by default does nothing, and it is recommended to override it from within the Sketch.

The first argument will be the index in the dictionary, the other two are the key states on the left and right halves, respectively.

Plugins that build upon this extensions should not override this function, but provide helpers that can be called from it. An override should only happen in the Sketch.

Further reading

Starting from the example is the recommended way of getting started with the plugin.