Use compose key instead of unicode input (#1)

Author: zapling

README.md

@@ -9,11 +9,7 @@ If you're interested in getting yourself an Atreus62 keyboards, it can be purcha
 
 This is my custom layout which is based on the US keyboard layout with some extra modifications for the Swedish characters `åäö`. It consists of three layers where some special keys are accessible while holding the `FN` key. 
 
-Input of Swedish characters under US layout is achieved with the unicode input mode that is available in Linux via (the `ctrl` + `shift` + `u`) key combination. You can read more about this at the [QMKs Unicode section](https://beta.docs.qmk.fm/using-qmk/software-features/feature_unicode#input-modes).
-
-_This mode is not accesible under Windows, and therefore this layout might not work as expected for those users._
-
-Some applications behave unexpectedly when trying to input characters this way, resulting in some weird behaviour. To circumvent this, one workaround is to temporarily change the keyboard layout to Swedish in your OS. If you know a better way, please consider creating a PR.
+Input of Swedish characters under US layout is achieved with the usage of `compose` key. You can read more about this at the [Arch wiki](https://wiki.archlinux.org/title/Xorg/Keyboard_configuration#Configuring_compose_key).
 
 ## Installation
 

zapling/keymap.c

@@ -13,17 +13,17 @@ enum custom_keys {
   KEY_EUR
 };
 
-// Custom unicode characters
-const char LOWER_A_DIACRITIC[] = "0x00e5"; // å
-const char UPPER_A_DIACRITIC[] = "0x00c5"; // Å
+// Custom keys with compose-key instructions
+const char LOWER_A_DIACRITIC[] = "oa"; // å
+const char UPPER_A_DIACRITIC[] = "oA"; // Å
 
-const char LOWER_A_DIAERESIS[] = "0x00e4"; // ä
-const char UPPER_A_DIAERESIS[] = "0x00c4"; // Ä
+const char LOWER_A_DIAERESIS[] = "\"a"; // ä
+const char UPPER_A_DIAERESIS[] = "\"A"; // Ä
 
-const char LOWER_O_DIAERESIS[] = "0x00f6"; // ö
-const char UPPER_O_DIAERESIS[] = "0x00d6"; // Ö
+const char LOWER_O_DIAERESIS[] = "\"o"; // ö
+const char UPPER_O_DIAERESIS[] = "\"O"; // Ö
 
-const char EURO_SIGN[] = "0x20ac"; // €
+const char EURO_SIGN[] = "=e"; // €
 
 /**
 * Return true if the shift modifier pressed
@@ -35,23 +35,47 @@ bool is_shift_pressed(void) {
   return false;
 }
 
-/**
-* Print a custom unicode character
-* Uses the linux unicode input mode in order to convert the unicode to a real character.
-* This might not always work, depending on the application.
-*
-* Uses the function 'send_string' in lowercase that allows for a char param.
-*/
-void print_unicode_char(const char* chars) {
-  SEND_STRING(
-    SS_DOWN(X_LCTL)
-    SS_DOWN(X_LSFT)
-    "u"
-    SS_UP(X_LCTL)
-    SS_UP(X_LSFT)
-  );
-  send_string(chars);
-  SEND_STRING(SS_TAP(X_ENT));
+struct Shift_States {
+    bool LeftShift;
+    bool RightShift;
+};
+
+struct Shift_States get_shift_states(void) {
+    struct Shift_States state = {
+        keyboard_report->mods & MOD_BIT(KC_LSFT),
+        keyboard_report->mods & MOD_BIT(KC_RSFT)
+    };
+    return state;
+}
+
+/*
+ * Uses compose key to get characters that are not usally accessable under US layout.
+ * Relieas on that 'X_APP' aka Menu button is set as the compose key in OS.
+ * See https://wiki.archlinux.org/title/Xorg/Keyboard_configuration#Configuring_compose_key
+ *
+ * Will release all shift modifiers temporarily and return it's state when done.
+ */
+void compose_character(const char* chars) {
+    struct Shift_States state = get_shift_states();
+
+    // release shift modifiers
+    if (state.LeftShift == true) {
+        SEND_STRING(SS_UP(X_LSFT));
+    }
+    if (state.RightShift == true) {
+        SEND_STRING(SS_UP(X_RSFT));
+    }
+
+    SEND_STRING(SS_TAP(X_APP));
+    send_string(chars);
+
+    // return shift modifiers
+    if (state.LeftShift == true) {
+        SEND_STRING(SS_DOWN(X_LSFT));
+    }
+    if (state.RightShift == true) {
+        SEND_STRING(SS_DOWN(X_RSFT));
+    }
 }
 
 /**
@@ -61,25 +85,25 @@ bool process_record_user(uint16_t keycode, keyrecord_t *record) {
   switch (keycode) {
     case KC_A_DIACRITIC: // å key
       if (record->event.pressed) {
-        is_shift_pressed() ? print_unicode_char(UPPER_A_DIACRITIC) : print_unicode_char(LOWER_A_DIACRITIC);
+        is_shift_pressed() ? compose_character(UPPER_A_DIACRITIC) : compose_character(LOWER_A_DIACRITIC);
       }
       break;
 
     case KC_A_DIAERESIS: // ä key
       if (record->event.pressed) {
-        is_shift_pressed() ? print_unicode_char(UPPER_A_DIAERESIS) : print_unicode_char(LOWER_A_DIAERESIS);
+        is_shift_pressed() ? compose_character(UPPER_A_DIAERESIS) : compose_character(LOWER_A_DIAERESIS);
       }
       break;
 
     case KC_O_DIAERESIS: // ö key
       if (record->event.pressed) {
-        is_shift_pressed() ? print_unicode_char(UPPER_O_DIAERESIS) : print_unicode_char(LOWER_O_DIAERESIS);
+        is_shift_pressed() ? compose_character(UPPER_O_DIAERESIS) : compose_character(LOWER_O_DIAERESIS);
       }
       break;
 
     case KEY_EUR: // €
       if (record->event.pressed) {
-        print_unicode_char(EURO_SIGN);
+        compose_character(EURO_SIGN);
       }
   }
   return true;
@@ -112,4 +136,4 @@ const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
     TO(0),  TO(0),  TO(0),  TO(0),  TO(0),  TO(0),                  TO(0),  TO(0),  TO(0),  TO(0),  TO(0),  TO(0),
     TO(0),  TO(0),  TO(0),  TO(0),  TO(0),  TO(0),  RESET,  RESET,  TO(0),  TO(0),  TO(0),  TO(0),  TO(0),  TO(0)
   )
-};
+};