Hangul support (#595)

* Hangul support

This works with two new kinds of keys (Hangul_initial and Hangul_medial)
that carry a precomposed hangul syllable and act as modifiers.

The hangul syllables are composed algorithmically.

* Add shift layer to Dubeolsik layout

srcs/juloo.keyboard2/KeyModifier.java

@@ -52,6 +52,12 @@ public final class KeyModifier
         return modify(k, mod.getModifier());
       case Compose_pending:
         return ComposeKey.apply(mod.getPendingCompose(), k);
+      case Hangul_initial:
+        if (k.equals(mod)) // Allow typing the initial in letter form
+          return KeyValue.makeStringKey(k.getString(), KeyValue.FLAG_GREYED);
+        return combine_hangul_initial(k, mod.getHangulPrecomposed());
+      case Hangul_medial:
+        return combine_hangul_medial(k, mod.getHangulPrecomposed());
     }
     return k;
   }
@@ -1234,4 +1240,108 @@ public final class KeyModifier
         }
       }
     };
+
+  /** Compose the precomposed initial with the medial [kv]. */
+  private static KeyValue combine_hangul_initial(KeyValue kv, int precomposed)
+  {
+    switch (kv.getKind())
+    {
+      case Char:
+        return combine_hangul_initial(kv, kv.getChar(), precomposed);
+      case Hangul_initial:
+        // No initials are expected to compose, grey out
+        return kv.withFlags(kv.getFlags() | KeyValue.FLAG_GREYED);
+      default:
+        return kv;
+    }
+  }
+
+  private static KeyValue combine_hangul_initial(KeyValue kv, char medial,
+      int precomposed)
+  {
+    int medial_idx;
+    switch (medial)
+    {
+      // Vowels
+      case 'ㅏ': medial_idx = 0; break;
+      case 'ㅐ': medial_idx = 1; break;
+      case 'ㅑ': medial_idx = 2; break;
+      case 'ㅒ': medial_idx = 3; break;
+      case 'ㅓ': medial_idx = 4; break;
+      case 'ㅔ': medial_idx = 5; break;
+      case 'ㅕ': medial_idx = 6; break;
+      case 'ㅖ': medial_idx = 7; break;
+      case 'ㅗ': medial_idx = 8; break;
+      case 'ㅘ': medial_idx = 9; break;
+      case 'ㅙ': medial_idx = 10; break;
+      case 'ㅚ': medial_idx = 11; break;
+      case 'ㅛ': medial_idx = 12; break;
+      case 'ㅜ': medial_idx = 13; break;
+      case 'ㅝ': medial_idx = 14; break;
+      case 'ㅞ': medial_idx = 15; break;
+      case 'ㅟ': medial_idx = 16; break;
+      case 'ㅠ': medial_idx = 17; break;
+      case 'ㅡ': medial_idx = 18; break;
+      case 'ㅢ': medial_idx = 19; break;
+      case 'ㅣ': medial_idx = 20; break;
+      // Grey-out uncomposable characters
+      default: return kv.withFlags(kv.getFlags() | KeyValue.FLAG_GREYED);
+    }
+    return KeyValue.makeHangulMedial(precomposed, medial_idx);
+  }
+
+  /** Combine the precomposed medial with the final [kv]. */
+  private static KeyValue combine_hangul_medial(KeyValue kv, int precomposed)
+  {
+    switch (kv.getKind())
+    {
+      case Char:
+        return combine_hangul_medial(kv, kv.getChar(), precomposed);
+      case Hangul_initial:
+        // Finals that can also be initials have this kind.
+        return combine_hangul_medial(kv, kv.getString().charAt(0), precomposed);
+      default:
+        return kv;
+    }
+  }
+
+  private static KeyValue combine_hangul_medial(KeyValue kv, char c,
+      int precomposed)
+  {
+    int final_idx;
+    switch (c)
+    {
+      case ' ': final_idx = 0; break;
+      case 'ㄱ': final_idx = 1; break;
+      case 'ㄲ': final_idx = 2; break;
+      case 'ㄳ': final_idx = 3; break;
+      case 'ㄴ': final_idx = 4; break;
+      case 'ㄵ': final_idx = 5; break;
+      case 'ㄶ': final_idx = 6; break;
+      case 'ㄷ': final_idx = 7; break;
+      case 'ㄹ': final_idx = 8; break;
+      case 'ㄺ': final_idx = 9; break;
+      case 'ㄻ': final_idx = 10; break;
+      case 'ㄼ': final_idx = 11; break;
+      case 'ㄽ': final_idx = 12; break;
+      case 'ㄾ': final_idx = 13; break;
+      case 'ㄿ': final_idx = 14; break;
+      case 'ㅀ': final_idx = 15; break;
+      case 'ㅁ': final_idx = 16; break;
+      case 'ㅂ': final_idx = 17; break;
+      case 'ㅄ': final_idx = 18; break;
+      case 'ㅅ': final_idx = 19; break;
+      case 'ㅆ': final_idx = 20; break;
+      case 'ㅇ': final_idx = 21; break;
+      case 'ㅈ': final_idx = 22; break;
+      case 'ㅊ': final_idx = 23; break;
+      case 'ㅋ': final_idx = 24; break;
+      case 'ㅌ': final_idx = 25; break;
+      case 'ㅍ': final_idx = 26; break;
+      case 'ㅎ': final_idx = 27; break;
+      // Grey-out uncomposable characters
+      default: return kv.withFlags(kv.getFlags() | KeyValue.FLAG_GREYED);
+    }
+    return KeyValue.makeHangulFinal(precomposed, final_idx);
+  }
 }

srcs/juloo.keyboard2/KeyValue.java

@@ -86,8 +86,8 @@ public final class KeyValue implements Comparable<KeyValue>
 
   public static enum Kind
   {
-    Char, String, Keyevent, Event, Compose_pending, Modifier, Editing,
-    Placeholder,
+    Char, String, Keyevent, Event, Compose_pending, Hangul_initial,
+    Hangul_medial, Modifier, Editing, Placeholder,
     Cursor_move // Value is encoded as a 16-bit integer
   }
 
@@ -195,6 +195,13 @@ public final class KeyValue implements Comparable<KeyValue>
     return (_code & VALUE_BITS);
   }
 
+  /** Defined only when [getKind()] is [Kind.Hangul_initial] or
+      [Kind.Hangul_medial]. */
+  public int getHangulPrecomposed()
+  {
+    return (_code & VALUE_BITS);
+  }
+
   /** Defined only when [getKind() == Kind.Cursor_move]. */
   public short getCursorMove()
   {
@@ -368,6 +375,25 @@ public final class KeyValue implements Comparable<KeyValue>
         flags | FLAG_KEY_FONT);
   }
 
+  public static KeyValue makeHangulInitial(String symbol, int initial_idx)
+  {
+    return new KeyValue(symbol, Kind.Hangul_initial, initial_idx * 588 + 44032,
+        FLAG_LATCH);
+  }
+
+  public static KeyValue makeHangulMedial(int precomposed, int medial_idx)
+  {
+    precomposed += medial_idx * 28;
+    return new KeyValue(String.valueOf((char)precomposed), Kind.Hangul_medial,
+        precomposed, FLAG_LATCH);
+  }
+
+  public static KeyValue makeHangulFinal(int precomposed, int final_idx)
+  {
+    precomposed += final_idx;
+    return KeyValue.makeCharKey((char)precomposed);
+  }
+
   /** Make a key that types a string. A char key is returned for a string of
       length 1. */
   public static KeyValue makeStringKey(String str, int flags)
@@ -538,6 +564,27 @@ public final class KeyValue implements Comparable<KeyValue>
       case "f11_placeholder": return placeholderKey(Placeholder.F11);
       case "f12_placeholder": return placeholderKey(Placeholder.F12);
 
+      // Korean Hangul
+      case "ㄱ": return makeHangulInitial("ㄱ", 0);
+      case "ㄲ": return makeHangulInitial("ㄲ", 1);
+      case "ㄴ": return makeHangulInitial("ㄴ", 2);
+      case "ㄷ": return makeHangulInitial("ㄷ", 3);
+      case "ㄸ": return makeHangulInitial("ㄸ", 4);
+      case "ㄹ": return makeHangulInitial("ㄹ", 5);
+      case "ㅁ": return makeHangulInitial("ㅁ", 6);
+      case "ㅂ": return makeHangulInitial("ㅂ", 7);
+      case "ㅃ": return makeHangulInitial("ㅃ", 8);
+      case "ㅅ": return makeHangulInitial("ㅅ", 9);
+      case "ㅆ": return makeHangulInitial("ㅆ", 10);
+      case "ㅇ": return makeHangulInitial("ㅇ", 11);
+      case "ㅈ": return makeHangulInitial("ㅈ", 12);
+      case "ㅉ": return makeHangulInitial("ㅉ", 13);
+      case "ㅊ": return makeHangulInitial("ㅊ", 14);
+      case "ㅋ": return makeHangulInitial("ㅋ", 15);
+      case "ㅌ": return makeHangulInitial("ㅌ", 16);
+      case "ㅍ": return makeHangulInitial("ㅍ", 17);
+      case "ㅎ": return makeHangulInitial("ㅎ", 18);
+
       /* Fallback to a string key that types its name */
       default: return makeStringKey(name);
     }

srcs/layouts/hang_dubeolsik_kr.xml

@@ -1,5 +1,16 @@
 <?xml version="1.0" encoding="utf-8"?>
 <keyboard name="두벌식 (Korean)" script="hangul">
+  <modmap>
+    <!-- The hangul character don't have shifted variants, this is specific to
+         the layout. -->
+    <shift a="ㅂ" b="ㅃ"/>
+    <shift a="ㅈ" b="ㅉ"/>
+    <shift a="ㄷ" b="ㄸ"/>
+    <shift a="ㄱ" b="ㄲ"/>
+    <shift a="ㅅ" b="ㅆ"/>
+    <shift a="ㅐ" b="ㅒ"/>
+    <shift a="ㅔ" b="ㅖ"/>
+  </modmap>
   <row>
     <key key0="ㅂ" key2="1" key4="esc"/>
     <key key0="ㅈ" key1="~" key2="2" key3="\@"/>