virtual size

examples/code_viewer.py

@@ -29,7 +29,9 @@ class MyApp(App):
 
         await self.view.dock(Header(), edge="top")
         await self.view.dock(Footer(), edge="bottom")
-        await self.view.dock(self.directory, edge="left", size=32, name="sidebar")
+        await self.view.dock(
+            ScrollView(self.directory), edge="left", size=32, name="sidebar"
+        )
         await self.view.dock(self.body, edge="right")
 
     async def message_file_click(self, message: FileClick) -> None:

src/textual/events.py

@@ -127,7 +127,7 @@ class Show(Event):
 
 
 class Hide(Event):
-    """Send when a widget has been hidden.
+    """Sent when a widget has been hidden.
 
     A widget may be hidden by setting its `visible` flag to `False`, if it is no longer in a layout,
     or if it has been offset beyond the edges of the terminal.

src/textual/layout_map.py

@@ -17,12 +17,13 @@ class RenderRegion(NamedTuple):
 
 class LayoutMap:
     def __init__(self, size: Dimensions) -> None:
-        self.region = size.region
+        self.size = size
+        self.contents_region = Region(0, 0, 0, 0)
         self.widgets: dict[Widget, RenderRegion] = {}
 
     @property
-    def size(self) -> Dimensions:
-        return self.region.size
+    def virtual_size(self) -> Dimensions:
+        return self.contents_region.size
 
     def __getitem__(self, widget: Widget) -> RenderRegion:
         return self.widgets[widget]
@@ -51,7 +52,7 @@ class LayoutMap:
 
         region += widget.layout_offset
         self.widgets[widget] = RenderRegion(region, order, clip)
-        self.region = self.region.union(region)
+        self.contents_region = self.contents_region.union(region)
 
         if isinstance(widget, View):
             sub_map = widget.layout.generate_map(

src/textual/view.py

@@ -56,9 +56,11 @@ class View(Widget):
     def scroll(self) -> Offset:
         return Offset(self.scroll_x, self.scroll_y)
 
-    @property
-    def virtual_size(self) -> Dimensions:
-        return self.layout.map.size if self.layout.map else Dimensions(0, 0)
+    virtual_size: Reactive[Dimensions] = Reactive(Dimensions(0, 0))
+
+    # @property
+    # def virtual_size(self) -> Dimensions:
+    #     return self.layout.map.size if self.layout.map else Dimensions(0, 0)
 
     # virtual_width: Reactive[int | None] = Reactive(None)
     # virtual_height: Reactive[int | None] = Reactive(None)
@@ -157,6 +159,7 @@ class View(Widget):
         hidden, shown, resized = self.layout.reflow(
             self.console, width, height, self.scroll
         )
+        self.virtual_size = self.layout.map.virtual_size
         self.app.refresh()
 
         for widget in hidden:

src/textual/views/_window_view.py

@@ -2,12 +2,18 @@ from __future__ import annotations
 
 from rich.console import RenderableType
 
+from ..geometry import Offset, Dimensions
 from ..layouts.vertical import VerticalLayout
 from ..view import View
+from ..message import Message
 from ..widget import Widget
 from ..widgets import Static
 
 
+class VirtualSizeChange(Message):
+    pass
+
+
 class WindowView(View, layout=VerticalLayout):
     def __init__(
         self,
@@ -26,4 +32,8 @@ class WindowView(View, layout=VerticalLayout):
         assert isinstance(layout, VerticalLayout)
         layout.clear()
         layout.add(widget if isinstance(widget, Widget) else Static(widget))
+        await self.refresh_layout()
         self.require_layout()
+
+    async def watch_virtual_size(self, size: Dimensions) -> None:
+        await self.emit(VirtualSizeChange(self))

src/textual/widgets/_scroll_view.py

@@ -9,11 +9,11 @@ from .. import events
 from ..layouts.grid import GridLayout
 from ..message import Message
 from ..scrollbar import ScrollTo, ScrollBar
-from ..geometry import clamp
+from ..geometry import clamp, Offset, Dimensions
 from ..page import Page
+from ..reactive import watch
 from ..view import View
-from ..widgets import Placeholder
-
+from ..widget import Widget
 
 from ..reactive import Reactive
 
@@ -21,7 +21,7 @@ from ..reactive import Reactive
 class ScrollView(View):
     def __init__(
         self,
-        renderable: RenderableType | None = None,
+        contents: RenderableType | Widget | None = None,
         *,
         name: str | None = None,
         style: StyleType = "",
@@ -32,7 +32,7 @@ class ScrollView(View):
         self.fluid = fluid
         self.vscroll = ScrollBar(vertical=True)
         self.hscroll = ScrollBar(vertical=False)
-        self.window = WindowView("" if renderable is None else renderable)
+        self.window = WindowView("" if contents is None else contents)
         layout = GridLayout()
         layout.add_column("main")
         layout.add_column("vscroll", size=1)
@@ -70,9 +70,11 @@ class ScrollView(View):
     async def watch_y(self, new_value: float) -> None:
         self.window.scroll_y = round(new_value)
         self.vscroll.position = round(new_value)
+        # self.window.require_repaint()
+        self.window.require_layout()
 
-    async def update(self, renderabe: RenderableType) -> None:
-        await self.window.update(renderabe)
+    async def update(self, renderable: RenderableType) -> None:
+        await self.window.update(renderable)
 
     async def on_mount(self, event: events.Mount) -> None:
         assert isinstance(self.layout, GridLayout)
@@ -172,19 +174,17 @@ class ScrollView(View):
         self.animate("x", self.target_x, speed=150, easing="out_cubic")
         self.animate("y", self.target_y, speed=150, easing="out_cubic")
 
-    async def message_page_update(self, message: Message) -> None:
+    async def message_virtual_size_change(self, message: Message) -> None:
+        virtual_size = self.window.virtual_size
+        self.log("VIRTUAL_SIZE", self.size, virtual_size)
         self.x = self.validate_x(self.x)
         self.y = self.validate_y(self.y)
-        self.vscroll.virtual_size = self.window.virtual_size.height
+        self.vscroll.virtual_size = virtual_size.height
         self.vscroll.window_size = self.size.height
 
         assert isinstance(self.layout, GridLayout)
 
-        if self.layout.show_column(
-            "vscroll", self.window.virtual_size.height > self.size.height
-        ):
+        if self.layout.show_column("vscroll", virtual_size.height > self.size.height):
             self.require_layout()
-        if self.layout.show_row(
-            "hscroll", self.window.virtual_size.width > self.size.width
-        ):
+        if self.layout.show_row("hscroll", virtual_size.width > self.size.width):
             self.require_layout()