Added mouse support to ScrollablePane.

Author: jonathanslenders

examples/full-screen/scrollable-panes/with-completion-menu.py

@@ -73,7 +73,9 @@ def exit(event) -> None:
     kb.add("s-tab")(focus_previous)
 
     # Create and run application.
-    application = Application(layout=layout, key_bindings=kb, full_screen=True)
+    application = Application(
+        layout=layout, key_bindings=kb, full_screen=True, mouse_support=True
+    )
     application.run()
 
 

prompt_toolkit/key_binding/bindings/mouse.py

@@ -94,7 +94,7 @@ def _(event: E) -> None:
                 return
 
             # Call the mouse handler from the renderer.
-            handler = event.app.renderer.mouse_handlers.mouse_handlers[x, y]
+            handler = event.app.renderer.mouse_handlers.mouse_handlers[y][x]
             handler(MouseEvent(position=Point(x=x, y=y), event_type=mouse_event_type))
 
     @key_bindings.add(Keys.ScrollUp)

prompt_toolkit/layout/mouse_handlers.py

@@ -5,9 +5,12 @@
 from prompt_toolkit.mouse_events import MouseEvent
 
 __all__ = [
+    "MouseHandler",
     "MouseHandlers",
 ]
 
+MouseHandler = Callable[[MouseEvent], None]
+
 
 class MouseHandlers:
     """
@@ -20,10 +23,14 @@ def dummy_callback(mouse_event: MouseEvent) -> None:
             :param mouse_event: `MouseEvent` instance.
             """
 
-        # Map (x,y) tuples to handlers.
+        # NOTE: Previously, the data structure was a dictionary mapping (x,y)
+        # to the handlers. This however would be more inefficient when copying
+        # over the mouse handlers of the visible region in the scrollable pane.
+
+        # Map y (row) to x (column) to handlers.
         self.mouse_handlers: DefaultDict[
-            Tuple[int, int], Callable[[MouseEvent], None]
-        ] = defaultdict(lambda: dummy_callback)
+            int, DefaultDict[int, MouseHandler]
+        ] = defaultdict(lambda: defaultdict(lambda: dummy_callback))
 
     def set_mouse_handler_for_range(
         self,
@@ -36,5 +43,8 @@ def set_mouse_handler_for_range(
         """
         Set mouse handler for a region.
         """
-        for x, y in product(range(x_min, x_max), range(y_min, y_max)):
-            self.mouse_handlers[x, y] = handler
+        for y in range(y_min, y_max):
+            row = self.mouse_handlers[y]
+
+            for x in range(x_min, x_max):
+                row[x] = handler

prompt_toolkit/layout/scrollable_pane.py

@@ -3,10 +3,11 @@
 from prompt_toolkit.data_structures import Point
 from prompt_toolkit.filters import FilterOrBool, to_filter
 from prompt_toolkit.key_binding import KeyBindingsBase
+from prompt_toolkit.mouse_events import MouseEvent
 
 from .containers import Container, ScrollOffsets
 from .dimension import AnyDimension, Dimension, sum_layout_dimensions, to_dimension
-from .mouse_handlers import MouseHandlers
+from .mouse_handlers import MouseHandler, MouseHandlers
 from .screen import Char, Screen, WritePosition
 
 __all__ = ["ScrollablePane"]
@@ -199,10 +200,44 @@ def write_to_screen(
                 if x in temp_zero_width_escapes:
                     zero_width_escapes[x + xpos] = temp_zero_width_escapes[x]
 
+        # Copy over mouse handlers.
+        mouse_handlers_dict = mouse_handlers.mouse_handlers
+        temp_mouse_handlers_dict = temp_mouse_handlers.mouse_handlers
+
+        # Cache mouse handlers when wrapping them. Very often the same mouse
+        # handler is registered for many positions.
+        mouse_handler_wrappers: Dict[MouseHandler, MouseHandler] = {}
+
+        def wrap_mouse_handler(handler: MouseHandler) -> MouseHandler:
+            " Wrap mouse handler. Translate coordinates in `MouseEvent`. "
+            if handler not in mouse_handler_wrappers:
+
+                def new_handler(event: MouseEvent) -> None:
+                    new_event = MouseEvent(
+                        position=Point(
+                            x=event.position.x - xpos,
+                            y=event.position.y + self.vertical_scroll - ypos,
+                        ),
+                        event_type=event.event_type,
+                    )
+                    handler(new_event)
+
+                mouse_handler_wrappers[handler] = new_handler
+            return mouse_handler_wrappers[handler]
+
+        for y in range(write_position.height):
+            if y in temp_mouse_handlers_dict:
+                temp_mouse_row = temp_mouse_handlers_dict[y + self.vertical_scroll]
+                mouse_row = mouse_handlers_dict[y + ypos]
+                for x in range(virtual_width):
+                    if x in temp_mouse_row:
+                        mouse_row[x + xpos] = wrap_mouse_handler(temp_mouse_row[x])
+
         # Set screen.width/height.
         screen.width = max(screen.width, xpos + virtual_width)
         screen.height = max(screen.height, ypos + write_position.height)
 
+        # Copy over window write positions.
         for win, write_pos in temp_screen.visible_windows_to_write_positions.items():
             screen.visible_windows_to_write_positions[win] = WritePosition(
                 xpos=write_pos.xpos + xpos,