Kaleidoscope-ModifierLayers

ModifierLayers is a plugin that lets you specify non-standard effects of modifier keys using a keymap.

For example in the Programmer Dvorak keyboard layout, the top row of the keyboard contains the symbols $&[{}(=*)+]!#, while numbers can be typed by pressing Shift and one of the symbols. The keys of the shifted and unshifted layers are rearranged independently when compared to a QWERTY layout.

This plugin lets you specify overlay keymaps to use when modifier keys are held. For any transparent entry in the overlay keymap, the appropriate key from the layers underneath will be selected and combined with the modifier. For any non-transparent entry, that entry will be used without applying the modifier (this allows mapping Shift + ) = 2, where the 2 is unshifted).

The ModifierLayers plugin also takes care of rollover effects. If you define Shift + ) = 2 and press Shift + ) + a, your computer will receive either 2 or A, depending on the order you pressed the keys, and not @ (the result of doing Shift + 2 on a QWERTY keyboard.)

Using the plugin

To use the plugin, you should define your keymap layers, create an array to specify which overlay layers to use, and configure the provided ModifierLayers object to use the array. Here is an example for setting up Programmer Dvorak:

#include <Kaleidoscope.h>
#include <Kaleidoscope-ModifierLayers.h>

enum { PDVORAK, PDVORAK_NUMBERS };

const Key keymaps[][ROWS][COLS] PROGMEM = {
    [PDVORAK] = // ... (omitted)
    [PDVORAK_NUMBERS] = // ... (omitted)
  };
}

static const kaleidoscope::ModifierLayers::overlay_t overlays[] = {
  {
      LAYER_MODIFIER_KEY(Key_LeftShift) | LAYER_MODIFIER_KEY(Key_RightShift),
      PDVORAK,
      PDVORAK_NUMBERS
  },
  {0, 0, 0}
};

void setup() {
  Kaleidoscope.setup();
  Kaleidoscope.use(&ModifierLayers);
  ModifierLayers.overlays = overlays;
}

Each overlay entry contains three pieces of information:

• A set of modifier keys, any of which will activate the overlay
• The base layer: the overlay will only activate when the base layer is active
• The overlay layer

The final entry in the list must be {0, 0, 0}.

Example

A more complete Programmer Dvorak example is located in the examples/ folder.