Automatic capitalisation at beginning of sentences

Keep track of end-of-sentence characters while typing and automatically
enable shift when appropriate.

The last few characters just before the cursor need to be queried in
some cases: Begin of input, cursor has moved or text is deleted.
This might have a performance cost.

This normally only enable shift but it also needs to disable shift when
the cursor moves.

1 files changed, 119 insertions, 0 deletions

diff --git a/srcs/juloo.keyboard2/Autocapitalisation.java b/srcs/juloo.keyboard2/Autocapitalisation.java
new file mode 100644
index 0000000..1affdab
--- /dev/null
+++ b/srcs/juloo.keyboard2/Autocapitalisation.java
@@ -0,0 +1,119 @@
+package juloo.keyboard2;
+
+import android.text.InputType;
+import android.text.TextUtils;
+import android.view.inputmethod.EditorInfo;
+import android.view.inputmethod.InputConnection;
+import android.view.KeyEvent;
+
+final class Autocapitalisation
+{
+  private boolean _enabled = false;
+  private boolean _beginning_of_sentence = false;
+
+  /** Keep track of the cursor to differentiate 'selection_updated' events
+      corresponding to typing from cursor movement. */
+  private int _cursor = 0;
+
+  public boolean should_enable_shift()
+  {
+    return _enabled && _beginning_of_sentence;
+  }
+
+  /** Returns [true] if shift should be on initially. The input connection
+      isn't stored. */
+  public void started(EditorInfo info, InputConnection ic)
+  {
+    if ((info.inputType & InputType.TYPE_TEXT_FLAG_CAP_SENTENCES) == 0)
+    {
+      _enabled = false;
+      return;
+    }
+    _enabled = true;
+    _beginning_of_sentence = ((info.initialCapsMode & TextUtils.CAP_MODE_SENTENCES) != 0);
+    _cursor = 0; // Just a guess
+    scan_text_before_cursor(10, ic);
+  }
+
+  public void typed(CharSequence c)
+  {
+    for (int i = 0; i < c.length(); i++)
+      typed(c.charAt(i));
+  }
+
+  public void typed(char c)
+  {
+    _cursor++;
+    if (is_beginning_of_sentence(c))
+      _beginning_of_sentence = true;
+    else if (!ignore_at_beginning_of_sentence(c))
+      _beginning_of_sentence = false;
+  }
+
+  public void selection_updated(int old_cursor, int new_cursor, InputConnection ic)
+  {
+    if (new_cursor == _cursor)
+      return;
+    // Text has been inserted
+    if (old_cursor == _cursor && new_cursor > old_cursor)
+    {
+      scan_text_before_cursor(Math.min(new_cursor - old_cursor, 10), ic);
+    }
+    else
+    {
+      // Cursor has moved or [_cursor] wasn't uptodate
+      _beginning_of_sentence = false;
+      scan_text_before_cursor(10, ic);
+    }
+    _cursor = new_cursor;
+  }
+
+  /** Updates [_cursor]. */
+  private void scan_text_before_cursor(int range, InputConnection ic)
+  {
+    if (!_enabled) // Don't query characters if disabled
+      return;
+    CharSequence text_before = ic.getTextBeforeCursor(range, 0);
+    if (text_before == null)
+    {
+      _beginning_of_sentence = false;
+    }
+    else
+    {
+      _beginning_of_sentence = true;
+      typed(text_before);
+    }
+  }
+
+  private boolean ignore_at_beginning_of_sentence(char c)
+  {
+    switch (c)
+    {
+      case ' ':
+      case '"':
+      case '\'':
+      case '(':
+      case '«':
+        return true;
+      default:
+        return false;
+    }
+  }
+
+  private boolean is_beginning_of_sentence(char c)
+  {
+    switch (c)
+    {
+      case '.':
+      case ';':
+      case '\n':
+      case '!':
+      case '?':
+      case '¿':
+      case '¡':
+        return true;
+      default:
+        return false;
+    }
+  }
+}