add greedy

Author: willmcgugan

src/textual/_arrange.py

@@ -32,7 +32,11 @@ def _build_layers(widgets: Iterable[Widget]) -> Mapping[str, Sequence[Widget]]:
 
 
 def arrange(
-    widget: Widget, children: Sequence[Widget], size: Size, viewport: Size
+    widget: Widget,
+    children: Sequence[Widget],
+    size: Size,
+    viewport: Size,
+    optimal: bool = False,
 ) -> DockArrangeResult:
     """Arrange widgets by applying docks and calling layouts
 
@@ -56,7 +60,6 @@ def arrange(
 
     # Widgets which will be displayed
     display_widgets = [child for child in children if get_display(child) != "none"]
-
     # Widgets organized into layers
     layers = _build_layers(display_widgets)
 
@@ -80,7 +83,7 @@ def arrange(
         # Arrange docked widgets
         if dock_widgets:
             _dock_placements, dock_spacing = _arrange_dock_widgets(
-                dock_widgets, dock_region, viewport
+                dock_widgets, dock_region, viewport, greedy=not optimal
             )
             placements.extend(_dock_placements)
             dock_region = dock_region.shrink(dock_spacing)
@@ -92,7 +95,7 @@ def arrange(
         if layout_widgets:
             # Arrange layout widgets (i.e. not docked)
             layout_placements = widget.layout.arrange(
-                widget, layout_widgets, dock_region.size
+                widget, layout_widgets, dock_region.size, greedy=not optimal
             )
             scroll_spacing = scroll_spacing.grow_maximum(dock_spacing)
             placement_offset = dock_region.offset
@@ -118,11 +121,12 @@ def arrange(
 
             placements.extend(layout_placements)
 
+        widget.log(placements)
     return DockArrangeResult(placements, set(display_widgets), scroll_spacing)
 
 
 def _arrange_dock_widgets(
-    dock_widgets: Sequence[Widget], region: Region, viewport: Size
+    dock_widgets: Sequence[Widget], region: Region, viewport: Size, greedy: bool = True
 ) -> tuple[list[WidgetPlacement], Spacing]:
     """Arrange widgets which are *docked*.
 
@@ -150,7 +154,7 @@ def _arrange_dock_widgets(
         edge = dock_widget.styles.dock
 
         box_model = dock_widget._get_box_model(
-            size, viewport, Fraction(size.width), Fraction(size.height)
+            size, viewport, Fraction(size.width), Fraction(size.height), greedy=greedy
         )
         widget_width_fraction, widget_height_fraction, margin = box_model
         widget_width = int(widget_width_fraction) + margin.width

src/textual/_resolve.py

@@ -222,6 +222,7 @@ def resolve_box_models(
     viewport_size: Size,
     margin: Size,
     resolve_dimension: Literal["width", "height"] = "width",
+    greedy: bool = True,
 ) -> list[BoxModel]:
     """Resolve box models for a list of dimensions
 
@@ -263,6 +264,7 @@ def resolve_box_models(
                     if (_height := fraction_height - margin_height) < 0
                     else _height
                 ),
+                greedy=greedy,
             )
         )
         for (_dimension, widget, (margin_width, margin_height)) in zip(
@@ -334,10 +336,7 @@ def resolve_box_models(
     box_models = [
         box_model
         or widget._get_box_model(
-            size,
-            viewport_size,
-            width_fraction,
-            height_fraction,
+            size, viewport_size, width_fraction, height_fraction, greedy=greedy
         )
         for widget, box_model in zip(widgets, box_models)
     ]

src/textual/css/scalar.py

@@ -283,6 +283,8 @@ def resolve(
 
         if unit == Unit.PERCENT:
             unit = percent_unit
+        # elif unit == Unit.AUTO:
+        #     unit = Unit.FRACTION
         try:
             dimension = RESOLVE_MAP[unit](
                 value, size, viewport, fraction_unit or _FRACTION_ONE

src/textual/layout.py

@@ -210,7 +210,11 @@ def __repr__(self) -> str:
 
     @abstractmethod
     def arrange(
-        self, parent: Widget, children: list[Widget], size: Size
+        self,
+        parent: Widget,
+        children: list[Widget],
+        size: Size,
+        greedy: bool = True,
     ) -> ArrangeResult:
         """Generate a layout map that defines where on the screen the widgets will be drawn.
 
@@ -237,7 +241,8 @@ def get_content_width(self, widget: Widget, container: Size, viewport: Size) ->
             width = 0
         else:
             arrangement = widget._arrange(
-                Size(0 if widget.shrink else container.width, 0)
+                Size(0 if widget.shrink else container.width, 0),
+                optimal=True,
             )
             width = arrangement.total_region.right
         return width

src/textual/layouts/grid.py

@@ -31,7 +31,7 @@ def __init__(self) -> None:
         """If self.shrink is `True`, auto-detect and limit the width."""
 
     def arrange(
-        self, parent: Widget, children: list[Widget], size: Size
+        self, parent: Widget, children: list[Widget], size: Size, greedy: bool = True
     ) -> ArrangeResult:
         parent.pre_layout(self)
         styles = parent.styles
@@ -309,6 +309,7 @@ def apply_height_limits(widget: Widget, height: int) -> int:
                 Fraction(cell_size.width),
                 Fraction(cell_size.height),
                 constrain_width=True,
+                greedy=greedy,
             )
 
             if self.stretch_height and len(children) > 1:

src/textual/layouts/horizontal.py

@@ -20,7 +20,7 @@ class HorizontalLayout(Layout):
     name = "horizontal"
 
     def arrange(
-        self, parent: Widget, children: list[Widget], size: Size
+        self, parent: Widget, children: list[Widget], size: Size, greedy: bool = True
     ) -> ArrangeResult:
         parent.pre_layout(self)
         placements: list[WidgetPlacement] = []
@@ -57,6 +57,7 @@ def arrange(
             viewport,
             resolve_margin,
             resolve_dimension="width",
+            greedy=greedy,
         )
 
         margins = [

src/textual/layouts/vertical.py

@@ -18,7 +18,7 @@ class VerticalLayout(Layout):
     name = "vertical"
 
     def arrange(
-        self, parent: Widget, children: list[Widget], size: Size
+        self, parent: Widget, children: list[Widget], size: Size, greedy: bool = True
     ) -> ArrangeResult:
         parent.pre_layout(self)
         placements: list[WidgetPlacement] = []
@@ -57,6 +57,7 @@ def arrange(
             parent.app.size,
             resolve_margin,
             resolve_dimension="height",
+            greedy=greedy,
         )
 
         margins = [

src/textual/screen.py

@@ -513,6 +513,7 @@ def get_maximize_widgets(maximized: Widget) -> list[Widget]:
             ),
             size,
             self.screen.size,
+            False,
         )
 
         return arrangement

src/textual/widget.py

@@ -66,7 +66,7 @@
 from textual.css.match import match
 from textual.css.parse import parse_selectors
 from textual.css.query import NoMatches, WrongType
-from textual.css.scalar import ScalarOffset
+from textual.css.scalar import Scalar, ScalarOffset
 from textual.dom import DOMNode, NoScreen
 from textual.geometry import (
     NULL_REGION,
@@ -327,6 +327,8 @@ class Widget(DOMNode):
     """Rich renderable may expand beyond optimal size."""
     shrink: Reactive[bool] = Reactive(True)
     """Rich renderable may shrink below optimal size."""
+    greedy: Reactive[bool] = Reactive(True)
+    """Fraction widths will consume as much space as possible."""
     auto_links: Reactive[bool] = Reactive(True)
     """Widget will highlight links automatically."""
     disabled: Reactive[bool] = Reactive(False)
@@ -1185,7 +1187,7 @@ def render_str(self, text_content: str | Content) -> Content:
             return text_content
         return Content.from_markup(text_content)
 
-    def _arrange(self, size: Size) -> DockArrangeResult:
+    def _arrange(self, size: Size, optimal: bool = False) -> DockArrangeResult:
         """Arrange children.
 
         Args:
@@ -1194,13 +1196,13 @@ def _arrange(self, size: Size) -> DockArrangeResult:
         Returns:
             Widget locations.
         """
-        cache_key = (size, self._nodes._updates)
+        cache_key = (size, self._nodes._updates, optimal)
         cached_result = self._arrangement_cache.get(cache_key)
         if cached_result is not None:
             return cached_result
 
         arrangement = self._arrangement_cache[cache_key] = arrange(
-            self, self._nodes, size, self.screen.size
+            self, self._nodes, size, self.screen.size, optimal=optimal
         )
 
         return arrangement
@@ -1541,6 +1543,7 @@ def _get_box_model(
         width_fraction: Fraction,
         height_fraction: Fraction,
         constrain_width: bool = False,
+        greedy: bool = True,
     ) -> BoxModel:
         """Process the box model for this widget.
 
@@ -1555,14 +1558,17 @@ def _get_box_model(
             The size and margin for this widget.
         """
         styles = self.styles
-        _content_width, _content_height = container
-        content_width = Fraction(_content_width)
-        content_height = Fraction(_content_height)
+        # _content_width, _content_height = container
+        # content_width = Fraction(_content_width)
+        # content_height = Fraction(_content_height)
         is_border_box = styles.box_sizing == "border-box"
         gutter = styles.gutter  # Padding plus border
         margin = styles.margin
 
-        is_auto_width = styles.width and styles.width.is_auto
+        styles_width = styles.width
+        if not greedy and styles_width is not None and styles_width.is_fraction:
+            styles_width = Scalar.parse("auto")
+        is_auto_width = styles_width and styles_width.is_auto
         is_auto_height = styles.height and styles.height.is_auto
 
         # Container minus padding and border
@@ -1573,7 +1579,7 @@ def _get_box_model(
         )
         min_width, max_width, min_height, max_height = extrema
 
-        if styles.width is None:
+        if styles_width is None:
             # No width specified, fill available space
             content_width = Fraction(content_container.width - margin.width)
         elif is_auto_width:
@@ -1592,7 +1598,6 @@ def _get_box_model(
                 content_width = Fraction(content_container.width)
         else:
             # An explicit width
-            styles_width = styles.width
             content_width = styles_width.resolve(
                 container - margin.totals, viewport, width_fraction
             )
@@ -2193,6 +2198,8 @@ def _has_relative_children_width(self) -> bool:
         if not self.is_container:
             return False
         for child in self.children:
+            if not child.greedy:
+                continue
             styles = child.styles
             if styles.display == "none":
                 continue
@@ -3326,6 +3333,8 @@ def scroll_to_widget(
         scrolled = False
 
         if not region.size:
+            if on_complete is not None:
+                self.call_after_refresh(on_complete)
             return False
 
         while isinstance(widget.parent, Widget) and widget is not self:
@@ -3418,6 +3427,8 @@ def scroll_to_region(
             window = window.shrink(spacing)
 
         if window in region and not (top or center):
+            if on_complete is not None:
+                self.call_after_refresh(on_complete)
             return Offset()
 
         def clamp_delta(delta: Offset) -> Offset:
@@ -3471,6 +3482,9 @@ def clamp_delta(delta: Offset) -> Offset:
                 level=level,
                 immediate=immediate,
             )
+        else:
+            if on_complete is not None:
+                self.call_after_refresh(on_complete)
         return delta
 
     def scroll_visible(