refreshing invisible widgets is a no-op

CHANGELOG.md

@@ -7,8 +7,13 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## Unreleased
 
+### Fixed
+
+- Fixed issue with screen not updating when auto_refresh was enabled https://github.com/Textualize/textual/pull/5063
+
 ### Added
 
+- Added `DOMNode.is_on_screen` property https://github.com/Textualize/textual/pull/5063
 - Added support for keymaps (user configurable key bindings) https://github.com/Textualize/textual/pull/5038
 
 ## [0.81.0] - 2024-09-25

src/textual/_compositor.py

@@ -311,9 +311,6 @@ def __init__(self) -> None:
         # Mapping of line numbers on to lists of widget and regions
         self._layers_visible: list[list[tuple[Widget, Region, Region]]] | None = None
 
-        # New widgets added between updates
-        self._new_widgets: set[Widget] = set()
-
     def clear(self) -> None:
         """Remove all references to widgets (used when the screen closes)."""
         self._full_map.clear()
@@ -392,8 +389,7 @@ def reflow(self, parent: Widget, size: Size) -> ReflowResult:
         new_widgets = map.keys()
 
         # Newly visible widgets
-        shown_widgets = (new_widgets - old_widgets) | self._new_widgets
-        self._new_widgets.clear()
+        shown_widgets = new_widgets - old_widgets
 
         # Newly hidden widgets
         hidden_widgets = self.widgets - widgets
@@ -490,7 +486,6 @@ def full_map(self) -> CompositorMap:
             self._full_map_invalidated = False
             map, _widgets = self._arrange_root(self.root, self.size, visible_only=False)
             # Update any widgets which became visible in the interim
-            self._new_widgets.update(map.keys() - self._full_map.keys())
             self._full_map = map
             self._visible_widgets = None
             self._visible_map = None
@@ -803,6 +798,22 @@ def layers_visible(self) -> list[list[tuple[Widget, Region, Region]]]:
             self._layers_visible = layers_visible
         return self._layers_visible
 
+    def __contains__(self, widget: Widget) -> bool:
+        """Check if the widget was included in the last update.
+
+        Args:
+            widget: A widget.
+
+        Returns:
+            `True` if the widget was in the last refresh, or `False` if it wasn't.
+        """
+        # Try to avoid a recalculation of full_map if possible.
+        return (
+            widget in self.widgets
+            or (self._visible_map is not None and widget in self._visible_map)
+            or widget in self.full_map
+        )
+
     def get_offset(self, widget: Widget) -> Offset:
         """Get the offset of a widget.
 

src/textual/dom.py

@@ -489,6 +489,11 @@ def is_modal(self) -> bool:
         """Is the node a modal?"""
         return False
 
+    @property
+    def is_on_screen(self) -> bool:
+        """Check if the node was displayed in the last screen update."""
+        return False
+
     def automatic_refresh(self) -> None:
         """Perform an automatic refresh.
 
@@ -497,7 +502,7 @@ def automatic_refresh(self) -> None:
         during an automatic refresh.
 
         """
-        if self.display and self.visible:
+        if self.is_on_screen:
             self.refresh()
 
     def __init_subclass__(

src/textual/screen.py

@@ -147,6 +147,7 @@ class Screen(Generic[ScreenResultType], Widget):
 
     DEFAULT_CSS = """
     Screen {
+
         layout: vertical;
         overflow-y: auto;
         background: $surface;        
@@ -162,11 +163,11 @@ class Screen(Generic[ScreenResultType], Widget):
             background: ansi_default;
             color: ansi_default;
 
-            &.-screen-suspended {
+            &.-screen-suspended {                                            
+                text-style: dim;
                 ScrollBar {
                     text-style: not dim;
                 }
-                text-style: dim;
             }
         }
     }
@@ -1136,8 +1137,9 @@ async def _on_update(self, message: messages.Update) -> None:
         widget = message.widget
         assert isinstance(widget, Widget)
 
-        self._dirty_widgets.add(widget)
-        self.check_idle()
+        if self in self._compositor:
+            self._dirty_widgets.add(widget)
+            self.check_idle()
 
     async def _on_layout(self, message: messages.Layout) -> None:
         message.stop()

src/textual/widget.py

@@ -1927,6 +1927,15 @@ def _has_relative_children_height(self) -> bool:
                 return True
         return False
 
+    @property
+    def is_on_screen(self) -> bool:
+        """Check if the node was displayed in the last screen update."""
+        try:
+            self.screen.find_widget(self)
+        except (NoScreen, errors.NoWidget):
+            return False
+        return True
+
     def animate(
         self,
         attribute: str,

tests/snapshot_tests/test_snapshots.py

@@ -23,6 +23,7 @@
     Footer,
     Log,
     OptionList,
+    Placeholder,
     SelectionList,
 )
 from textual.widgets import ProgressBar, Label, Switch
@@ -2098,3 +2099,38 @@ def action_toggle_console(self) -> None:
 
     app = MRE()
     assert snap_compare(app, press=["space", "space", "z"])
+
+
+def test_updates_with_auto_refresh(snap_compare):
+    """Regression test for https://github.com/Textualize/textual/issues/5056
+
+    After hiding and unhiding the RichLog, you should be able to see 1.5 fully rendered placeholder widgets.
+    Prior to this fix, the bottom portion of the screen did not 
+    refresh after the RichLog was hidden/unhidden while in the presence of the auto-refreshing ProgressBar widget.
+    """
+
+    class MRE(App):
+        BINDINGS = [
+            ("z", "toggle_widget('RichLog')", "Console"),
+        ]
+        CSS = """
+        Placeholder { height: 15; }
+        RichLog { height: 6; }
+        .hidden { display: none; }
+        """
+
+        def compose(self):
+            with VerticalScroll():
+                for i in range(10):
+                    yield Placeholder()
+            yield ProgressBar(classes="hidden")
+            yield RichLog(classes="hidden")
+
+        def on_ready(self) -> None:
+            self.query_one(RichLog).write("\n".join(f"line #{i}" for i in range(5)))
+
+        def action_toggle_widget(self, widget_type: str) -> None:
+            self.query_one(widget_type).toggle_class("hidden")
+
+    app = MRE()
+    assert snap_compare(app, press=["z", "z"])