1 files changed, 56 insertions, 0 deletions
diff --git a/src/prompt_toolkit/layout/mouse_handlers.py b/src/prompt_toolkit/layout/mouse_handlers.py
new file mode 100644
index 0000000..56a4edd
--- /dev/null
+++ b/src/prompt_toolkit/layout/mouse_handlers.py
@@ -0,0 +1,56 @@
+from __future__ import annotations
+
+from collections import defaultdict
+from typing import TYPE_CHECKING, Callable
+
+from prompt_toolkit.mouse_events import MouseEvent
+
+if TYPE_CHECKING:
+    from prompt_toolkit.key_binding.key_bindings import NotImplementedOrNone
+
+__all__ = [
+    "MouseHandler",
+    "MouseHandlers",
+]
+
+
+MouseHandler = Callable[[MouseEvent], "NotImplementedOrNone"]
+
+
+class MouseHandlers:
+    """
+    Two dimensional raster of callbacks for mouse events.
+    """
+
+    def __init__(self) -> None:
+        def dummy_callback(mouse_event: MouseEvent) -> NotImplementedOrNone:
+            """
+            :param mouse_event: `MouseEvent` instance.
+            """
+            return NotImplemented
+
+        # 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[
+            int, defaultdict[int, MouseHandler]
+        ] = defaultdict(lambda: defaultdict(lambda: dummy_callback))
+
+    def set_mouse_handler_for_range(
+        self,
+        x_min: int,
+        x_max: int,
+        y_min: int,
+        y_max: int,
+        handler: Callable[[MouseEvent], NotImplementedOrNone],
+    ) -> None:
+        """
+        Set mouse handler for a region.
+        """
+        for y in range(y_min, y_max):
+            row = self.mouse_handlers[y]
+
+            for x in range(x_min, x_max):
+                row[x] = handler