Fix content width

src/textual/_doc.py

@@ -100,7 +100,7 @@ async def auto_pilot(pilot: Pilot) -> None:
         app = pilot.app
         await pilot.press(*press)
         await pilot.wait_for_scheduled_animations()
-        await pilot.pause()
+        await pilot.pause(0.05)
         svg = app.export_screenshot(title=title)
 
         app.exit(svg)

src/textual/_layout.py

@@ -25,6 +25,7 @@ class DockArrangeResult:
     """Shared spacing around the widgets."""
 
     _spatial_map: SpatialMap[WidgetPlacement] | None = None
+    """A Spatial map to query widget placements."""
 
     @property
     def spatial_map(self) -> SpatialMap[WidgetPlacement]:
@@ -111,14 +112,8 @@ def get_content_width(self, widget: Widget, container: Size, viewport: Size) ->
             width = 0
         else:
             # Use a size of 0, 0 to ignore relative sizes, since those are flexible anyway
-            placements = widget._arrange(Size(0, 0)).placements
-            width = max(
-                [
-                    placement.region.right + placement.margin.right
-                    for placement in placements
-                ],
-                default=0,
-            )
+            arrangement = widget._arrange(Size(0, 0))
+            return arrangement.total_region.right + arrangement.spacing.right
         return width
 
     def get_content_height(
@@ -139,13 +134,6 @@ def get_content_height(
             height = 0
         else:
             # Use a height of zero to ignore relative heights
-            placements = widget._arrange(Size(width, 0)).placements
-            height = max(
-                [
-                    placement.region.bottom + placement.margin.bottom
-                    for placement in placements
-                ],
-                default=0,
-            )
-
+            arrangement = widget._arrange(Size(width, 0))
+            height = arrangement.total_region.bottom + arrangement.spacing.bottom
         return height

src/textual/box_model.py

@@ -125,6 +125,7 @@ def get_box_model(
         content_height = min(content_height, max_height)
 
     content_height = max(Fraction(0), content_height)
+
     model = BoxModel(
         content_width + gutter.width, content_height + gutter.height, margin
     )

src/textual/cli/previews/colors.css

@@ -9,7 +9,7 @@ ColorButtons {
 }
 
 ColorButtons > Button {
-    width: 30;
+    width: 100%;
 }
 
 ColorsView {

src/textual/constants.py

@@ -3,7 +3,6 @@
 
 """
 
-
 import os
 
 from typing_extensions import Final

src/textual/demo.css

@@ -102,6 +102,7 @@ Column {
     height: auto;
     min-height: 100vh;
     align: center top;
+    overflow: hidden;
 }
 
 

src/textual/scroll_view.py

@@ -82,7 +82,7 @@ def _size_updated(
         Returns:
             True if anything changed, or False if nothing changed.
         """
-        if self._size != size or container_size != container_size:
+        if self._size != size or self._container_size != container_size:
             self.refresh()
         if (
             self._size != size

src/textual/scrollbar.py

@@ -197,7 +197,7 @@ def __rich_console__(
 class ScrollBar(Widget):
     renderer: ClassVar[Type[ScrollBarRender]] = ScrollBarRender
     """The class used for rendering scrollbars.
-    This can be overriden and set to a ScrollBarRender-derived class
+    This can be overridden and set to a ScrollBarRender-derived class
     in order to delegate all scrollbar rendering to that class. E.g.:
 
     ```

src/textual/widget.py

@@ -515,6 +515,8 @@ def _arrange(self, size: Size) -> DockArrangeResult:
     def _clear_arrangement_cache(self) -> None:
         """Clear arrangement cache, forcing a new arrange operation."""
         self._arrangement_cache.clear()
+        self._stabilized_scrollbar_size = None
+        self._scrollbar_stabilizer = 0
 
     def _get_virtual_dom(self) -> Iterable[Widget]:
         """Get widgets not part of the DOM.
@@ -848,14 +850,11 @@ def get_content_height(self, container: Size, viewport: Size, width: int) -> int
         """
         if self.is_container:
             assert self._layout is not None
-            height = (
-                self._layout.get_content_height(
-                    self,
-                    container,
-                    viewport,
-                    width,
-                )
-                + self.scrollbar_size_horizontal
+            height = self._layout.get_content_height(
+                self,
+                container,
+                viewport,
+                width,
             )
         else:
             cache_key = width
@@ -978,34 +977,36 @@ def _refresh_scrollbars(self) -> None:
         styles = self.styles
         overflow_x = styles.overflow_x
         overflow_y = styles.overflow_y
-        width, height = self.container_size
+        width, height = self._container_size
 
-        show_horizontal = self.show_horizontal_scrollbar
+        show_horizontal = False
         if overflow_x == "hidden":
             show_horizontal = False
         elif overflow_x == "scroll":
             show_horizontal = True
         elif overflow_x == "auto":
             show_horizontal = self.virtual_size.width > width
 
-        show_vertical = self.show_vertical_scrollbar
+        show_vertical = False
         if overflow_y == "hidden":
             show_vertical = False
         elif overflow_y == "scroll":
             show_vertical = True
         elif overflow_y == "auto":
             show_vertical = self.virtual_size.height > height
 
-        if (
-            overflow_x == "auto"
-            and show_vertical
-            and not show_horizontal
-            and self._stabilized_scrollbar_size != self.container_size
-        ):
-            show_horizontal = (
-                self.virtual_size.width + styles.scrollbar_size_vertical > width
-            )
-            self._stabilized_scrollbar_size = self.container_size
+        if self._stabilized_scrollbar_size != self.container_size:
+            # When a single scrollbar is shown, the other dimension changes, so we need to recalculate.
+            if show_vertical and not show_horizontal:
+                show_horizontal = self.virtual_size.width > (
+                    width - styles.scrollbar_size_vertical
+                )
+            if show_horizontal and not show_vertical:
+                show_vertical = self.virtual_size.height > (
+                    height - styles.scrollbar_size_horizontal
+                )
+
+        self._stabilized_scrollbar_size = self._container_size
 
         self.show_horizontal_scrollbar = show_horizontal
         self.show_vertical_scrollbar = show_vertical
@@ -2098,7 +2099,7 @@ def _arrange_scrollbars(self, region: Region) -> Iterable[tuple[Widget, Region]]
 
         if show_horizontal_scrollbar and show_vertical_scrollbar:
             (
-                _,
+                window_region,
                 vertical_scrollbar_region,
                 horizontal_scrollbar_region,
                 scrollbar_corner_gap,
@@ -2109,18 +2110,34 @@ def _arrange_scrollbars(self, region: Region) -> Iterable[tuple[Widget, Region]]
             if scrollbar_corner_gap:
                 yield self.scrollbar_corner, scrollbar_corner_gap
             if vertical_scrollbar_region:
-                yield self.vertical_scrollbar, vertical_scrollbar_region
+                scrollbar = self.vertical_scrollbar
+                scrollbar.window_virtual_size = self.virtual_size.height
+                scrollbar.window_size = window_region.height
+                yield scrollbar, vertical_scrollbar_region
             if horizontal_scrollbar_region:
-                yield self.horizontal_scrollbar, horizontal_scrollbar_region
+                scrollbar = self.horizontal_scrollbar
+                scrollbar.window_virtual_size = self.virtual_size.width
+                scrollbar.window_size = window_region.width
+                yield scrollbar, horizontal_scrollbar_region
 
         elif show_vertical_scrollbar:
-            _, scrollbar_region = region.split_vertical(-scrollbar_size_vertical)
+            window_region, scrollbar_region = region.split_vertical(
+                -scrollbar_size_vertical
+            )
             if scrollbar_region:
-                yield self.vertical_scrollbar, scrollbar_region
+                scrollbar = self.vertical_scrollbar
+                scrollbar.window_virtual_size = self.virtual_size.height
+                scrollbar.window_size = window_region.height
+                yield scrollbar, scrollbar_region
         elif show_horizontal_scrollbar:
-            _, scrollbar_region = region.split_horizontal(-scrollbar_size_horizontal)
+            window_region, scrollbar_region = region.split_horizontal(
+                -scrollbar_size_horizontal
+            )
             if scrollbar_region:
-                yield self.horizontal_scrollbar, scrollbar_region
+                scrollbar = self.horizontal_scrollbar
+                scrollbar.window_virtual_size = self.virtual_size.width
+                scrollbar.window_size = window_region.width
+                yield scrollbar, scrollbar_region
 
     def get_pseudo_classes(self) -> Iterable[str]:
         """Pseudo classes for a widget.
@@ -2239,9 +2256,13 @@ def _scroll_update(self, virtual_size: Size) -> None:
             self.vertical_scrollbar.window_size = (
                 height - self.scrollbar_size_horizontal
             )
+            if self.vertical_scrollbar._repaint_required:
+                self.call_next(self.vertical_scrollbar.refresh)
         if self.show_horizontal_scrollbar:
             self.horizontal_scrollbar.window_virtual_size = virtual_size.width
             self.horizontal_scrollbar.window_size = width - self.scrollbar_size_vertical
+            if self.horizontal_scrollbar._repaint_required:
+                self.call_next(self.horizontal_scrollbar.refresh)
 
         self.scroll_x = self.validate_scroll_x(self.scroll_x)
         self.scroll_y = self.validate_scroll_y(self.scroll_y)
@@ -2363,6 +2384,7 @@ def refresh(
         """
         if layout and not self._layout_required:
             self._layout_required = True
+            self._stabilized_scrollbar_size = None
             for ancestor in self.ancestors:
                 if not isinstance(ancestor, Widget):
                     break

src/textual/widgets/_text_log.py

@@ -8,7 +8,6 @@
 from rich.pretty import Pretty
 from rich.protocol import is_renderable
 from rich.segment import Segment
-from rich.style import Style
 from rich.text import Text
 
 from .._cache import LRUCache

tests/snapshot_tests/snapshot_apps/test_line_api_scrollbars.py

@@ -0,0 +1,54 @@
+from rich.text import Text
+
+from textual.app import App, ComposeResult
+from textual.containers import Vertical
+from textual.widget import Widget
+from textual.widgets import TextLog
+
+
+class MyWidget(Widget):
+    def render(self):
+        return Text(
+            "\n".join(f"{n} 0123456789" for n in range(20)),
+            no_wrap=True,
+            overflow="hidden",
+            justify="left",
+        )
+
+
+class ScrollViewApp(App):
+    CSS = """
+    Screen {
+        align: center middle;
+    }
+
+    TextLog {
+        width:13;
+        height:10;        
+    }
+
+    Vertical{
+        width:13;
+        height: 10;
+        overflow: scroll;
+        overflow-x: auto;
+    }
+    MyWidget {
+        width:13;
+        height:auto;
+    }
+
+    """
+
+    def compose(self) -> ComposeResult:
+        yield TextLog()
+        yield Vertical(MyWidget())
+
+    def on_ready(self) -> None:
+        self.query_one(TextLog).write("\n".join(f"{n} 0123456789" for n in range(20)))
+        self.query_one(Vertical).scroll_end(animate=False)
+
+
+if __name__ == "__main__":
+    app = ScrollViewApp()
+    app.run()

tests/snapshot_tests/test_snapshots.py

@@ -256,3 +256,7 @@ def test_disabled_widgets(snap_compare):
 
 def test_focus_component_class(snap_compare):
     assert snap_compare(SNAPSHOT_APPS_DIR / "focus_component_class.py", press=["tab"])
+
+
+def test_line_api_scrollbars(snap_compare):
+    assert snap_compare(SNAPSHOT_APPS_DIR / "test_line_api_scrollbars.py", press=["_"])