expose grid-size

CHANGELOG.md

@@ -12,6 +12,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Fixed `TextArea` cursor display on wrapped lines https://github.com/Textualize/textual/pull/6196
 - Fixed `remove_children` not refreshing layout https://github.com/Textualize/textual/pull/6206
 
+### Added
+
+- Added `grid_size` property to `GridLayout` https://github.com/Textualize/textual/pull/6210
+
 ## [6.5.0] - 2025-10-31
 
 ### Added

src/textual/layouts/grid.py

@@ -29,6 +29,17 @@ def __init__(self) -> None:
         """Shrink the grid to fit the container if it is larger."""
         self.auto_minimum: bool = False
         """If self.shrink is `True`, auto-detect and limit the width."""
+        self._grid_size: tuple[int, int] | None = None
+        """Grid size after last arrange call."""
+
+    @property
+    def grid_size(self) -> tuple[int, int] | None:
+        """The grid size after the last arrange call.
+
+        Returns:
+            A tuple of (WIDTH, HEIGHT) or `None` prior to the first `arrange`.
+        """
+        return self._grid_size
 
     def arrange(
         self, parent: Widget, children: list[Widget], size: Size, greedy: bool = True
@@ -60,6 +71,7 @@ def arrange(
                     table_size_columns -= 1
 
         table_size_rows = styles.grid_size_rows
+
         viewport = parent.app.viewport_size
         keyline_style, _keyline_color = styles.keyline
         offset = (0, 0)
@@ -157,9 +169,9 @@ def repeat_scalars(scalars: Iterable[Scalar], count: int) -> list[Scalar]:
             cell_coord = next_coord()
 
         column_scalars = repeat_scalars(column_scalars, table_size_columns)
-        row_scalars = repeat_scalars(
-            row_scalars, table_size_rows if table_size_rows else row + 1
-        )
+        table_size_rows = table_size_rows if table_size_rows else row + 1
+        row_scalars = repeat_scalars(row_scalars, table_size_rows)
+        self._grid_size = (table_size_columns, table_size_rows)
 
         def apply_width_limits(widget: Widget, width: int) -> int:
             """Apply min and max widths to dimension.

tests/layouts/test_grid.py

@@ -0,0 +1,34 @@
+from textual import containers, widgets
+from textual.app import App, ComposeResult
+from textual.layouts.grid import GridLayout
+
+
+async def test_grid_size():
+    """Test the `grid_size` property on GridLayout."""
+
+    class GridApp(App):
+        CSS = """
+        Grid {
+            grid-size: 3;
+            grid-columns: auto;
+            height: auto;
+            Label {
+                padding: 2 4;
+                border: blue;
+            }
+        }
+        """
+
+        def compose(self) -> ComposeResult:
+            with containers.VerticalScroll():
+                with containers.Grid():
+                    for _ in range(7):
+                        yield widgets.Label("Hello, World!")
+
+    app = GridApp()
+    async with app.run_test() as pilot:
+        await pilot.pause()
+        await app.wait_for_refresh()
+        grid_layout = app.query_one(containers.Grid).layout
+        assert isinstance(grid_layout, GridLayout)
+        assert grid_layout.grid_size == (3, 3)