Circle and round trip gestures (#640)

This implements clockwise/anticlockwise circle and round trip gestures
inspired by Messagease.

The circle gestures start after a small threshold to avoid making the
regular swipe too hard to aim.

The gestures do:

- circle: The center symbol with Shift applied, with a fallback on Fn
- round trip: Same as the circle gesture but applied to a side symbol
- anticlockwise circle: Nothing currently. It is intended to be made
  configurable per-layout in the future.

The new Gesture class keeps track of what the pointer is doing while it moves
on a key. It replaces the 'selected_direction' integer.

1 files changed, 13 insertions, 5 deletions

diff --git a/srcs/juloo.keyboard2/KeyModifier.java b/srcs/juloo.keyboard2/KeyModifier.java
index f358e97..a320ec5 100644
--- a/srcs/juloo.keyboard2/KeyModifier.java
+++ b/srcs/juloo.keyboard2/KeyModifier.java
@@ -33,7 +33,6 @@ public final class KeyModifier
     if (r == null)
     {
       r = k;
-      /* Order: Fn, Shift, accents */
       for (int i = 0; i < n_mods; i++)
         r = modify(r, mods.get(i));
       ks.put(mods, r);
@@ -70,6 +69,7 @@ public final class KeyModifier
       case ALT:
       case META: return turn_into_keyevent(k);
       case FN: return apply_fn(k);
+      case GESTURE: return apply_gesture(k);
       case SHIFT: return apply_shift(k);
       case GRAVE: return apply_map_char(k, map_char_grave);
       case AIGU: return apply_map_char(k, map_char_aigu);
@@ -139,11 +139,10 @@ public final class KeyModifier
       case Char:
         char kc = k.getChar();
         String modified = map.apply(kc);
-        if (modified == null)
-          return k;
-        return KeyValue.makeStringKey(modified, k.getFlags());
-      default: return k;
+        if (modified != null)
+          return KeyValue.makeStringKey(modified, k.getFlags());
     }
+    return k;
   }
 
   private static KeyValue apply_shift(KeyValue k)
@@ -482,6 +481,15 @@ public final class KeyModifier
     return k.withKeyevent(e);
   }
 
+  /** Modify a key affected by a round-trip or a clockwise circle gesture. */
+  private static KeyValue apply_gesture(KeyValue k)
+  {
+    KeyValue shifted = apply_shift(k);
+    if (shifted == null || shifted.equals(k))
+      return apply_fn(k);
+    return shifted;
+  }
+
   /* Lookup the cache entry for a key. Create it needed. */
   private static HashMap<Pointers.Modifiers, KeyValue> cacheEntry(KeyValue k)
   {