easing example

CHANGELOG.md

@@ -5,7 +5,7 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
-## [0.1.11] - Unreleased
+## [0.1.11] - 2021-09-12
 
 ### Changed
 

examples/easing.py

@@ -25,6 +25,7 @@ async def on_mount(self) -> None:
 
         self.placeholder = Placeholder()
         self.easing_view = DockView()
+        self.placeholder.style = "white on dark_blue"
 
         tree = TreeControl("Easing", {})
         for easing_key in sorted(EASING.keys()):

src/textual/app.py

@@ -416,10 +416,6 @@ async def on_event(self, event: events.Event) -> None:
         else:
             await super().on_event(event)
 
-    # async def on_idle(self, event: events.Idle) -> None:
-    #     if self.view.check_layout():
-    #         await self.view.refresh_layout()
-
     async def action(
         self,
         action: str,

src/textual/geometry.py

@@ -70,8 +70,8 @@ def blend(self, destination: Offset, factor: float) -> Offset:
 class Size(NamedTuple):
     """An area defined by its width and height."""
 
-    width: int
-    height: int
+    width: int = 0
+    height: int = 0
 
     def __bool__(self) -> bool:
         """A Size is Falsey if it has area 0."""

src/textual/layout_map.py

@@ -51,11 +51,12 @@ def add_widget(
         self.widgets[widget] = RenderRegion(region + widget.layout_offset, order, clip)
 
         if isinstance(widget, View):
-            scroll = widget.scroll
+            view: View = widget
+            scroll = view.scroll
             total_region = region.size.region
             sub_clip = clip.intersection(region)
 
-            arrangement = widget.layout.arrange(region.size, scroll)
+            arrangement = view.get_arrangement(region.size, scroll)
             for sub_region, sub_widget, sub_order in arrangement:
                 total_region = total_region.union(sub_region)
                 if sub_widget is not None:
@@ -65,4 +66,4 @@ def add_widget(
                         sub_order,
                         sub_clip,
                     )
-            widget.virtual_size = total_region.size
+            view.virtual_size = total_region.size

src/textual/layouts/vertical.py

@@ -2,13 +2,8 @@
 
 from typing import Iterable
 
-from rich.console import Console
-from rich.measure import Measurement
-
-from .. import log
 from ..geometry import Offset, Region, Size
 from ..layout import Layout, WidgetPlacement
-from ..layout_map import LayoutMap
 from ..widget import Widget
 
 
@@ -51,8 +46,7 @@ def arrange(self, size: Size, scroll: Offset) -> Iterable[WidgetPlacement]:
         x = gutter_width
         y = gutter_height
 
-        total_region = size.region
-
+        total_region = Region()
         for widget in self._widgets:
             if (
                 not widget.render_cache
@@ -65,4 +59,4 @@ def arrange(self, size: Size, scroll: Offset) -> Iterable[WidgetPlacement]:
             yield WidgetPlacement(region, widget, (self.z, index))
             total_region = total_region.union(region)
 
-        yield WidgetPlacement(total_region.expand(self.gutter))
+        yield WidgetPlacement(total_region)

src/textual/view.py

@@ -10,7 +10,7 @@
 from . import events
 from . import log
 from . import messages
-from .layout import Layout, NoWidget
+from .layout import Layout, NoWidget, WidgetPlacement
 from .geometry import Size, Offset, Region
 from .reactive import Reactive, watch
 
@@ -33,6 +33,13 @@ def __init__(self, layout: Layout = None, name: str | None = None) -> None:
         self.named_widgets: dict[str, Widget] = {}
         self._mouse_style: Style = Style()
         self._mouse_widget: Widget | None = None
+
+        self._cached_arrangement: tuple[Size, Offset, list[WidgetPlacement]] = (
+            Size(),
+            Offset(),
+            [],
+        )
+
         super().__init__(name=name)
 
     def __init_subclass__(
@@ -84,6 +91,14 @@ def render(self) -> RenderableType:
     def get_offset(self, widget: Widget) -> Offset:
         return self.layout.get_offset(widget)
 
+    def get_arrangement(self, size: Size, scroll: Offset) -> Iterable[WidgetPlacement]:
+        cached_size, cached_scroll, arrangement = self._cached_arrangement
+        if cached_size == size and cached_scroll == scroll:
+            return arrangement
+        arrangement = list(self.layout.arrange(size, scroll))
+        self._cached_arrangement = (size, scroll, arrangement)
+        return arrangement
+
     async def handle_update(self, message: messages.Update) -> None:
         if self.is_root_view:
             message.stop()
@@ -116,6 +131,7 @@ async def mount(self, *anon_widgets: Widget, **widgets: Widget) -> None:
         self.refresh()
 
     async def refresh_layout(self) -> None:
+        self._cached_arrangement = (Size(), Offset(), [])
         try:
             await self.layout.mount_all(self)
             if not self.is_root_view: