Add a keyboard input handling task

piker/ui/__init__.py

@@ -5,3 +5,5 @@ import os
 
 # use the trio async loop
 os.environ['KIVY_EVENTLOOP'] = 'trio'
+import kivy
+kivy.require('1.10.0')

piker/ui/kb.py

@@ -0,0 +1,57 @@
+"""
+VI-like Keyboard controls
+"""
+from kivy.core.window import Window
+
+from ..log import get_logger
+log = get_logger('keyboard')
+
+
+async def handle_input(widget, patts2funcs: dict, patt_len_limit=3):
+    """Handle keyboard inputs.
+
+    For each character pattern in ``patts2funcs`` invoke the corresponding
+    mapped functions.
+    """
+    def _kb_closed():
+        """Teardown handler.
+        """
+        log.debug('Closing keyboard controls')
+        print('Closing keyboard controls')
+        kb.unbind(on_key_down=_kb_closed)
+
+    last_patt = []
+
+    kb = Window.request_keyboard(_kb_closed, widget, 'text')
+    async for kb, keycode, text, modifiers in kb.async_bind(
+            'on_key_down'
+    ):
+        # log.debug(
+        log.debug(
+            f"Keyboard input received:\n"
+            f"key {keycode}\ntext {text}\nmodifiers {modifiers}"
+        )
+        code, key = keycode
+        if modifiers and key in modifiers:
+            continue
+        elif modifiers and key not in modifiers:
+            key = '-'.join(modifiers + [key])
+
+        # keep track of multi-key patterns
+        last_patt.append(key)
+
+        func = patts2funcs.get(tuple(last_patt))
+        if not func:
+            func = patts2funcs.get(key)
+
+        if func:
+            log.debug(f'invoking func kb {func}')
+            func()
+            last_patt = []
+        elif key == 'q':
+            kb.release()
+
+        if len(last_patt) > patt_len_limit:
+            last_patt = []
+
+        log.debug(f"last_patt {last_patt}")