[Keymap] addition: macro for "screenshot region to clipboard" in macOS (#5505)

* Create custom Planck Light keycap

See README for details

* Link to WhatPulse in README

* More remapping, and add RGB LED effects

* Remove dead code, address PR feedback from @drashna

* Add macro for “screenshot region to clipboard” hotkey for macOS

Also remove unused layer / key logic

* Remove extraneous comment

* Incorporate PR feedback from @drashna.

Update README with new mapping.

keyboards/planck/keymaps/tom/keymap.c

@@ -21,21 +21,14 @@ extern keymap_config_t keymap_config;
 
 enum planck_layers {
   _QWERTY,
-  _COLEMAK,
-  _DVORAK,
   _LOWER,
   _RAISE,
-  _PLOVER,
   _ADJUST
 };
 
 enum planck_keycodes {
   QWERTY = SAFE_RANGE,
-  COLEMAK,
-  DVORAK,
-  PLOVER,
-  BACKLIT,
-  EXT_PLV
+  BACKLIT
 };
 
 #define LOWER MO(_LOWER)
@@ -110,7 +103,7 @@ const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
  * `-----------------------------------------------------------------------------------'
  */
 [_ADJUST] = LAYOUT_planck_grid(
-    _______, RESET,   DEBUG,   RGB_TOG, RGB_MOD, RGB_HUI, RGB_HUD, RGB_SAI, RGB_SAD,  RGB_VAI, RGB_VAD, KC_DEL ,
+    C(G(S(KC_4))), RESET, DEBUG, RGB_TOG, RGB_MOD, RGB_HUI, RGB_HUD, RGB_SAI, RGB_SAD, RGB_VAI, RGB_VAD, KC_DEL,
     _______, _______, MU_MOD,  AU_ON,   AU_OFF,  AG_NORM, AG_SWAP, QWERTY,  _______,  _______, _______, _______,
     _______, MUV_DE,  MUV_IN,  MU_ON,   MU_OFF,  MI_ON,   MI_OFF,  TERM_ON, TERM_OFF, _______, _______, _______,
     _______, _______, _______, _______, _______, _______, _______, _______, _______,  _______, _______, _______
@@ -136,32 +129,6 @@ bool process_record_user(uint16_t keycode, keyrecord_t *record) {
       }
       return false;
       break;
-    case BACKLIT:
-      if (record->event.pressed) {
-        register_code(KC_RSFT);
-        #ifdef BACKLIGHT_ENABLE
-          backlight_step();
-        #endif
-        #ifdef KEYBOARD_planck_rev5
-          PORTE &= ~(1<<6);
-        #endif
-      } else {
-        unregister_code(KC_RSFT);
-        #ifdef KEYBOARD_planck_rev5
-          PORTE |= (1<<6);
-        #endif
-      }
-      return false;
-      break;
-    case EXT_PLV:
-      if (record->event.pressed) {
-        #ifdef AUDIO_ENABLE
-          PLAY_SONG(plover_gb_song);
-        #endif
-        layer_off(_PLOVER);
-      }
-      return false;
-      break;
   }
   return true;
 }

keyboards/planck/keymaps/tom/readme.md

@@ -25,6 +25,10 @@ This layout is data-driven: I installed [WhatPulse](https://whatpulse.org/) a fe
 - map brightness up / down to original location of left and up arrows
 - map volume up / down to original location of down and right arrows
 
+### ADJUST
+
+- map to esc key: screenshot region to clipboard - an alias for ctrl + cmd + shift + 4
+
 
 ## RGB LED