Merge pull request #6108 from Textualize/reduce-layout

Made arrange public

Author: willmcgugan

CHANGELOG.md

@@ -10,6 +10,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 ### Changed
 
 - Eager tasks are now enabled On Python3.12 and above https://github.com/Textualize/textual/pull/6102
+- `Widget._arrange` is now public (as `Widget.arrange`) https://github.com/Textualize/textual/pull/6108
+- Reduced number of layout operations required to update the screen https://github.com/Textualize/textual/pull/6108
 
 ### Added
 

src/textual/_compositor.py

@@ -597,7 +597,7 @@ def add_widget(
 
                 if widget.is_container:
                     # Arrange the layout
-                    arrange_result = widget._arrange(child_region.size)
+                    arrange_result = widget.arrange(child_region.size)
 
                     arranged_widgets = arrange_result.widgets
                     widgets.update(arranged_widgets)

src/textual/layout.py

@@ -240,7 +240,7 @@ def get_content_width(self, widget: Widget, container: Size, viewport: Size) ->
         if not widget._nodes:
             width = 0
         else:
-            arrangement = widget._arrange(
+            arrangement = widget.arrange(
                 Size(0 if widget.shrink else container.width, 0),
                 optimal=True,
             )
@@ -266,9 +266,9 @@ def get_content_height(
                 child.styles.is_dynamic_height for child in widget.displayed_children
             ):
                 # An exception for containers with all dynamic height widgets
-                arrangement = widget._arrange(Size(width, container.height))
+                arrangement = widget.arrange(Size(width, container.height))
             else:
-                arrangement = widget._arrange(Size(width, 0))
+                arrangement = widget.arrange(Size(width, 0))
             height = arrangement.total_region.height
         else:
             height = 0

src/textual/layouts/stream.py

@@ -6,7 +6,6 @@
 from textual.layout import ArrangeResult, Layout, WidgetPlacement
 
 if TYPE_CHECKING:
-
     from textual.widget import Widget
 
 
@@ -110,7 +109,7 @@ def get_content_height(
             Content height (in lines).
         """
         if widget._nodes:
-            arrangement = widget._arrange(Size(width, 0))
+            arrangement = widget.arrange(Size(width, 0))
             height = arrangement.total_region.height
         else:
             height = 0

src/textual/screen.py

@@ -468,7 +468,7 @@ def active_bindings(self) -> dict[str, ActiveBinding]:
 
         return bindings_map
 
-    def _arrange(self, size: Size) -> DockArrangeResult:
+    def arrange(self, size: Size) -> DockArrangeResult:
         """Arrange children.
 
         Args:

src/textual/widget.py

@@ -460,7 +460,7 @@ def __init__(
         self._content_height_cache: tuple[object, int] = (None, 0)
 
         self._arrangement_cache: FIFOCache[
-            tuple[Size, int, Widget | None], DockArrangeResult
+            tuple[Size, int, bool], DockArrangeResult
         ] = FIFOCache(4)
 
         self._styles_cache = StylesCache()
@@ -1264,11 +1264,14 @@ def render_str(self, text_content: str | Content) -> Content:
             return text_content
         return Content.from_markup(text_content)
 
-    def _arrange(self, size: Size, optimal: bool = False) -> DockArrangeResult:
-        """Arrange children.
+    def arrange(self, size: Size, optimal: bool = False) -> DockArrangeResult:
+        """Arrange child widgets.
+
+        This method is best left along, unless you have a deep understanding of what it does.
 
         Args:
             size: Size of container.
+            optimal: Whether fr units should expand the widget (`False`) or avoid expanding the widget (`True`).
 
         Returns:
             Widget locations.
@@ -4201,6 +4204,8 @@ def refresh(
                 if not isinstance(ancestor, Widget):
                     break
                 ancestor._clear_arrangement_cache()
+                if not ancestor.styles.auto_dimensions:
+                    break
 
         if recompose:
             self._recompose_required = True