From d49f2c2df71ae3e483564b68ca19b6a14bf22a55 Mon Sep 17 00:00:00 2001
From: David Stansby <dstansby@gmail.com>
Date: Fri, 18 Mar 2022 17:50:50 +0000
Subject: [PATCH] Add scrollable widgets

---
 magicgui/backends/_qtpy/widgets.py          | 18 ++++++++++++++++++
 magicgui/widgets/_bases/container_widget.py |  9 +++++++++
 magicgui/widgets/_protocols.py              |  8 ++++++++
 3 files changed, 35 insertions(+)

diff --git a/magicgui/backends/_qtpy/widgets.py b/magicgui/backends/_qtpy/widgets.py
index fcf038070..b46971702 100644
--- a/magicgui/backends/_qtpy/widgets.py
+++ b/magicgui/backends/_qtpy/widgets.py
@@ -385,6 +385,24 @@ def __init__(self, layout="vertical"):
         else:
             self._layout = QtW.QVBoxLayout()
         self._qwidget.setLayout(self._layout)
+        # Create a scroll widget, but don't use it initially
+        self._scroll = QtW.QScrollArea()
+        # Allow widget to resize when window is larger than min widget size
+        self._scroll.setWidgetResizable(True)
+
+    def _mgui_set_scrollable(self, scrollable: bool):
+        if scrollable == self._mgui_get_scrollable():
+            return
+
+        if scrollable:
+            # Transfer widget from MainWindow to ScrollArea
+            self._scroll.setWidget(self._qwidget)
+            self._qwidget = self._scroll
+        if not scrollable:
+            self._qwidget = self._scroll.takeWidget()
+
+    def _mgui_get_scrollable(self):
+        return self._scroll.widget() is not None
 
     def _mgui_insert_widget(self, position: int, widget: Widget):
         self._layout.insertWidget(position, widget.native)
diff --git a/magicgui/widgets/_bases/container_widget.py b/magicgui/widgets/_bases/container_widget.py
index c554f02b9..9ef98828c 100644
--- a/magicgui/widgets/_bases/container_widget.py
+++ b/magicgui/widgets/_bases/container_widget.py
@@ -216,6 +216,15 @@ def layout(self, value):
             "It is not yet possible to change layout after instantiation"
         )
 
+    @property
+    def scrollable(self) -> bool:
+        """Return if the widget can have scroll bars."""
+        return self._widget._mgui_get_scrollable()
+
+    @scrollable.setter
+    def scrollable(self, value: bool):
+        self._widget._mgui_set_scrollable(value)
+
     def reset_choices(self, *_: Any):
         """Reset choices for all Categorical subWidgets to the default state.
 
diff --git a/magicgui/widgets/_protocols.py b/magicgui/widgets/_protocols.py
index 043994e3f..1d8c5ea09 100644
--- a/magicgui/widgets/_protocols.py
+++ b/magicgui/widgets/_protocols.py
@@ -450,6 +450,14 @@ def _mgui_get_margins(self) -> tuple[int, int, int, int]:
     def _mgui_set_margins(self, margins: tuple[int, int, int, int]) -> None:
         raise NotImplementedError()
 
+    @abstractmethod
+    def _mgui_get_scrollable(self) -> bool:
+        raise NotImplementedError()
+
+    @abstractmethod
+    def _mgui_set_scrollable(self, scrollable: bool) -> None:
+        raise NotImplementedError()
+
 
 class MainWindowProtocol(ContainerProtocol, Protocol):
     """Application main widget."""