From 8d3b0f22eca8babf95470acf39fc626a1b0be1b4 Mon Sep 17 00:00:00 2001
From: Will McGugan <willmcgugan@gmail.com>
Date: Mon, 21 Nov 2022 17:33:31 +0100
Subject: [PATCH 01/12] first iteration of spatial map

---
 src/textual/_spatial_map.py | 101 ++++++++++++++++++++++++++++++++++++
 1 file changed, 101 insertions(+)
 create mode 100644 src/textual/_spatial_map.py

diff --git a/src/textual/_spatial_map.py b/src/textual/_spatial_map.py
new file mode 100644
index 000000000..eec69d8fe
--- /dev/null
+++ b/src/textual/_spatial_map.py
@@ -0,0 +1,101 @@
+from __future__ import annotations
+
+from collections import defaultdict
+from itertools import product
+from typing import Iterable, Mapping
+
+from ._layout import WidgetPlacement
+from .geometry import Region
+
+
+class SpatialMap:
+    """An object to return WidgetPlacements within a given region.
+
+    The widget area is split in to a regular grid of buckets. Each placement is assigned to
+    any bucket it overlaps, which may be 1 or more buckets.
+
+    The `get_placements` function will calculate which buckets overlap the screen area, and combine
+    the placements from those buckets. This generally means that widgets that aren't overlapping or
+    near the screen area can be quickly discarded. The result will typically be a superset of visible
+    placements, which can then be filtered normally.
+
+    """
+
+    def __init__(
+        self,
+        placements: Iterable[WidgetPlacement],
+        block_width: int = 80,
+        block_height: int = 80,
+    ) -> None:
+        self._placements = placements
+        self._block_width = block_width
+        self._block_height = block_height
+        self._map: defaultdict[tuple[int, int], list[WidgetPlacement]] | None = None
+
+    @property
+    def placement_map(self) -> Mapping[tuple[int, int], list[WidgetPlacement]]:
+        """A mapping of block coordinate on to widget placement.
+
+        Returns:
+            Mapping[tuple[int, int], list[WidgetPlacement]]: Mapping.
+        """
+        if self._map is None:
+            self._map = self._build_placements(self._placements)
+            return self._map
+        return self._map
+
+    def _build_placements(
+        self, placements: Iterable[WidgetPlacement]
+    ) -> defaultdict[tuple[int, int], list[WidgetPlacement]]:
+        """Add placements to map.
+
+        Args:
+            placements (Iterable[WidgetPlacement]): A number of placements.
+        """
+        map: defaultdict[tuple[int, int], list[WidgetPlacement]] = defaultdict(list)
+        get_bucket = map.__getitem__
+
+        block_width = self._block_width
+        block_height = self._block_height
+
+        for placement in placements:
+            x1, y1, width, height = placement.region
+            x2 = x1 + width
+            y2 = y1 + height
+            for coord in product(
+                range(x1 // block_width, x2 // block_width + 1),
+                range(y1 // block_height, y2 // block_height + 1),
+            ):
+                get_bucket(coord).append(placement)
+        return map
+
+    def get_placements(self, screen_region: Region) -> Iterable[WidgetPlacement]:
+        """Get placements that may overlap a given region. There may be false positives,
+        but no false negatives.
+
+        Args:
+            region (Region): Container region.
+
+        Returns:
+            set[WidgetPlacement]: Set of Widget placements.
+        """
+        x1, y1, width, height = screen_region
+        x2 = x1 + width
+        y2 = y1 + height
+        block_width = self._block_width
+        block_height = self._block_height
+
+        placements: set[WidgetPlacement] = set()
+        extend_placements = placements.update
+        map = self.placement_map
+        map_get = map.get
+
+        for coord in product(
+            range(x1 // block_width, x2 // block_width + 1),
+            range(y1 // block_height, y2 // block_height + 1),
+        ):
+            block_placements = map_get(coord)
+            if block_placements is not None:
+                extend_placements(block_placements)
+
+        return placements

From 2e698b12002b7067b82915f8ae0c6f291f55d92e Mon Sep 17 00:00:00 2001
From: Will McGugan <willmcgugan@gmail.com>
Date: Mon, 21 Nov 2022 17:54:33 +0100
Subject: [PATCH 02/12] promoted to public

---
 src/textual/{_spatial_map.py => spatial_map.py} | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
 rename src/textual/{_spatial_map.py => spatial_map.py} (97%)

diff --git a/src/textual/_spatial_map.py b/src/textual/spatial_map.py
similarity index 97%
rename from src/textual/_spatial_map.py
rename to src/textual/spatial_map.py
index eec69d8fe..416e2e8e1 100644
--- a/src/textual/_spatial_map.py
+++ b/src/textual/spatial_map.py
@@ -77,7 +77,7 @@ class SpatialMap:
             region (Region): Container region.
 
         Returns:
-            set[WidgetPlacement]: Set of Widget placements.
+            Iterable[WidgetPlacement]: A super-set of Widget placements that may be in the screen.
         """
         x1, y1, width, height = screen_region
         x2 = x1 + width

From 01a3838315c8cba3dc702382890e9e655132e008 Mon Sep 17 00:00:00 2001
From: Will McGugan <willmcgugan@gmail.com>
Date: Mon, 21 Nov 2022 18:04:33 +0100
Subject: [PATCH 03/12] docstring

---
 src/textual/spatial_map.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/textual/spatial_map.py b/src/textual/spatial_map.py
index 416e2e8e1..b8e9e8884 100644
--- a/src/textual/spatial_map.py
+++ b/src/textual/spatial_map.py
@@ -37,7 +37,7 @@ class SpatialMap:
         """A mapping of block coordinate on to widget placement.
 
         Returns:
-            Mapping[tuple[int, int], list[WidgetPlacement]]: Mapping.
+            Mapping[tuple[int, int], list[WidgetPlacement]]: Mapping of coord to list of placements.
         """
         if self._map is None:
             self._map = self._build_placements(self._placements)

From f84313dac7c649405f83e6f15d974c1271735f91 Mon Sep 17 00:00:00 2001
From: Will McGugan <willmcgugan@gmail.com>
Date: Wed, 23 Nov 2022 22:12:44 +0800
Subject: [PATCH 04/12] integrated spatial map

---
 src/textual/_compositor.py                    |  7 ++++-
 src/textual/_layout.py                        |  3 +-
 .../{spatial_map.py => _spatial_map.py}       | 31 ++++++++++---------
 src/textual/widget.py                         | 10 ++++--
 4 files changed, 31 insertions(+), 20 deletions(-)
 rename src/textual/{spatial_map.py => _spatial_map.py} (80%)

diff --git a/src/textual/_compositor.py b/src/textual/_compositor.py
index ab9d69eca..47305047e 100644
--- a/src/textual/_compositor.py
+++ b/src/textual/_compositor.py
@@ -381,9 +381,14 @@ class Compositor:
 
                 if widget.is_container:
                     # Arrange the layout
-                    placements, arranged_widgets, spacing = widget._arrange(
+                    spatial_map, arranged_widgets, spacing = widget._arrange(
                         child_region.size
                     )
+
+                    placements = spatial_map.get_placements(
+                        child_region.reset_offset.translate(widget.scroll_offset)
+                    )
+
                     widgets.update(arranged_widgets)
 
                     # An offset added to all placements
diff --git a/src/textual/_layout.py b/src/textual/_layout.py
index fc9f21173..25d2d27c7 100644
--- a/src/textual/_layout.py
+++ b/src/textual/_layout.py
@@ -8,9 +8,10 @@ from ._typing import TypeAlias
 
 if TYPE_CHECKING:
     from .widget import Widget
+    from ._spatial_map import SpatialMap
 
 ArrangeResult: TypeAlias = "tuple[list[WidgetPlacement], set[Widget]]"
-DockArrangeResult: TypeAlias = "tuple[list[WidgetPlacement], set[Widget], Spacing]"
+DockArrangeResult: TypeAlias = "SpacialMap, set[Widget], Spacing]"
 
 
 class WidgetPlacement(NamedTuple):
diff --git a/src/textual/spatial_map.py b/src/textual/_spatial_map.py
similarity index 80%
rename from src/textual/spatial_map.py
rename to src/textual/_spatial_map.py
index b8e9e8884..c55caa9a6 100644
--- a/src/textual/spatial_map.py
+++ b/src/textual/_spatial_map.py
@@ -2,10 +2,12 @@ from __future__ import annotations
 
 from collections import defaultdict
 from itertools import product
-from typing import Iterable, Mapping
+from operator import attrgetter
+from typing import Iterable, Mapping, Sequence
 
 from ._layout import WidgetPlacement
 from .geometry import Region
+from ._partition import partition
 
 
 class SpatialMap:
@@ -23,26 +25,23 @@ class SpatialMap:
 
     def __init__(
         self,
-        placements: Iterable[WidgetPlacement],
+        placements: Sequence[WidgetPlacement],
         block_width: int = 80,
         block_height: int = 80,
     ) -> None:
         self._placements = placements
         self._block_width = block_width
         self._block_height = block_height
+        self._fixed: list[WidgetPlacement] = []
         self._map: defaultdict[tuple[int, int], list[WidgetPlacement]] | None = None
 
-    @property
-    def placement_map(self) -> Mapping[tuple[int, int], list[WidgetPlacement]]:
-        """A mapping of block coordinate on to widget placement.
+        self.placement_map = self._build_placements(placements)
 
-        Returns:
-            Mapping[tuple[int, int], list[WidgetPlacement]]: Mapping of coord to list of placements.
-        """
-        if self._map is None:
-            self._map = self._build_placements(self._placements)
-            return self._map
-        return self._map
+    def __iter__(self) -> Iterable[WidgetPlacement]:
+        yield from self._placements
+
+    def __reversed__(self) -> Iterable[WidgetPlacement]:
+        yield from reversed(self._placements)
 
     def _build_placements(
         self, placements: Iterable[WidgetPlacement]
@@ -58,6 +57,8 @@ class SpatialMap:
         block_width = self._block_width
         block_height = self._block_height
 
+        placements, self._fixed = partition(attrgetter("fixed"), placements)
+
         for placement in placements:
             x1, y1, width, height = placement.region
             x2 = x1 + width
@@ -69,7 +70,7 @@ class SpatialMap:
                 get_bucket(coord).append(placement)
         return map
 
-    def get_placements(self, screen_region: Region) -> Iterable[WidgetPlacement]:
+    def get_placements(self, screen_region: Region) -> list[WidgetPlacement]:
         """Get placements that may overlap a given region. There may be false positives,
         but no false negatives.
 
@@ -85,7 +86,7 @@ class SpatialMap:
         block_width = self._block_width
         block_height = self._block_height
 
-        placements: set[WidgetPlacement] = set()
+        placements: set[WidgetPlacement] = set(self._fixed)
         extend_placements = placements.update
         map = self.placement_map
         map_get = map.get
@@ -98,4 +99,4 @@ class SpatialMap:
             if block_placements is not None:
                 extend_placements(block_placements)
 
-        return placements
+        return list(placements)
diff --git a/src/textual/widget.py b/src/textual/widget.py
index 3dc821e95..292b670ba 100644
--- a/src/textual/widget.py
+++ b/src/textual/widget.py
@@ -1,8 +1,8 @@
 from __future__ import annotations
 
-from collections import Counter
 from asyncio import Event as AsyncEvent
 from asyncio import Lock, create_task, wait
+from collections import Counter
 from fractions import Fraction
 from itertools import islice
 from operator import attrgetter
@@ -39,6 +39,7 @@ from ._context import active_app
 from ._easing import DEFAULT_SCROLL_EASING
 from ._layout import Layout
 from ._segment_tools import align_lines
+from ._spatial_map import SpatialMap
 from ._styles_cache import StylesCache
 from ._types import Lines
 from .await_remove import AwaitRemove
@@ -53,7 +54,6 @@ from .message import Message
 from .messages import CallbackType
 from .reactive import Reactive
 from .render import measure
-from .await_remove import AwaitRemove
 from .walk import walk_depth_first
 
 if TYPE_CHECKING:
@@ -426,7 +426,11 @@ class Widget(DOMNode):
             return self._arrangement
 
         self._arrangement_cache_key = arrange_cache_key
-        self._arrangement = arrange(self, self.children, size, self.screen.size)
+        placements, widgets, spacing = arrange(
+            self, self.children, size, self.screen.size
+        )
+        arrange_result = SpatialMap(placements), widgets, spacing
+        self._arrangement = arrange_result
         return self._arrangement
 
     def _clear_arrangement_cache(self) -> None:

From 68d74404740a1f69c3ea22cc74ba3532544b8675 Mon Sep 17 00:00:00 2001
From: Will McGugan <willmcgugan@gmail.com>
Date: Wed, 23 Nov 2022 23:13:58 +0800
Subject: [PATCH 05/12] fix for update region

---
 src/textual/_compositor.py           | 10 ++++------
 src/textual/_spatial_map.py          | 16 ++++++++++++++--
 src/textual/_styles_cache.py         | 26 +++++++++++++++++++++-----
 src/textual/css/_style_properties.py |  2 +-
 src/textual/css/styles.py            | 17 ++++++++++++-----
 5 files changed, 52 insertions(+), 19 deletions(-)

diff --git a/src/textual/_compositor.py b/src/textual/_compositor.py
index 47305047e..75dc2a51f 100644
--- a/src/textual/_compositor.py
+++ b/src/textual/_compositor.py
@@ -384,6 +384,9 @@ class Compositor:
                     spatial_map, arranged_widgets, spacing = widget._arrange(
                         child_region.size
                     )
+                    total_region = total_region.union(
+                        spatial_map.total_region.grow(spacing)
+                    )
 
                     placements = spatial_map.get_placements(
                         child_region.reset_offset.translate(widget.scroll_offset)
@@ -402,16 +405,11 @@ class Compositor:
                     get_layer_index = layers_to_index.get
 
                     # Add all the widgets
-                    for sub_region, margin, sub_widget, z, fixed in reversed(
-                        placements
-                    ):
+                    for sub_region, _, sub_widget, z, fixed in reversed(placements):
                         # Combine regions with children to calculate the "virtual size"
                         if fixed:
                             widget_region = sub_region + placement_offset
                         else:
-                            total_region = total_region.union(
-                                sub_region.grow(spacing + margin)
-                            )
                             widget_region = sub_region + placement_scroll_offset
 
                         widget_order = order + (
diff --git a/src/textual/_spatial_map.py b/src/textual/_spatial_map.py
index c55caa9a6..eb2685554 100644
--- a/src/textual/_spatial_map.py
+++ b/src/textual/_spatial_map.py
@@ -3,10 +3,10 @@ from __future__ import annotations
 from collections import defaultdict
 from itertools import product
 from operator import attrgetter
-from typing import Iterable, Mapping, Sequence
+from typing import Iterable, Sequence
 
 from ._layout import WidgetPlacement
-from .geometry import Region
+from .geometry import Region, Spacing
 from ._partition import partition
 
 
@@ -26,10 +26,12 @@ class SpatialMap:
     def __init__(
         self,
         placements: Sequence[WidgetPlacement],
+        *,
         block_width: int = 80,
         block_height: int = 80,
     ) -> None:
         self._placements = placements
+        self._total_region = Region()
         self._block_width = block_width
         self._block_height = block_height
         self._fixed: list[WidgetPlacement] = []
@@ -37,6 +39,8 @@ class SpatialMap:
 
         self.placement_map = self._build_placements(placements)
 
+        print("SPATIAL", len(placements))
+
     def __iter__(self) -> Iterable[WidgetPlacement]:
         yield from self._placements
 
@@ -57,6 +61,14 @@ class SpatialMap:
         block_width = self._block_width
         block_height = self._block_height
 
+        self.total_region = Region.from_union(
+            [
+                placement.region.grow(placement.margin)
+                for placement in placements
+                if not placement.fixed
+            ]
+        )
+
         placements, self._fixed = partition(attrgetter("fixed"), placements)
 
         for placement in placements:
diff --git a/src/textual/_styles_cache.py b/src/textual/_styles_cache.py
index 8fa39e047..f3b738cce 100644
--- a/src/textual/_styles_cache.py
+++ b/src/textual/_styles_cache.py
@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+from functools import lru_cache
+from sys import intern
 from typing import TYPE_CHECKING, Callable, Iterable, List
 
 from rich.segment import Segment
@@ -52,6 +54,20 @@ def style_links(
     return segments
 
 
+@lru_cache(1024 * 8)
+def make_blank(width, style: Style) -> Segment:
+    """Make a blank segment.
+
+    Args:
+        width (_type_): Width of blank.
+        style (Style): Style of blank.
+
+    Returns:
+        Segment: A single segment
+    """
+    return Segment(intern(" " * width), style)
+
+
 class StylesCache:
     """Responsible for rendering CSS Styles and keeping a cache of rendered lines.
 
@@ -319,20 +335,20 @@ class StylesCache:
             right_style = from_color(color=(background + border_right_color).rich_color)
             right = get_box(border_right, inner, outer, right_style)[1][2]
             if border_left and border_right:
-                line = [left, Segment(" " * (width - 2), background_style), right]
+                line = [left, make_blank(width - 2, background_style), right]
             elif border_left:
-                line = [left, Segment(" " * (width - 1), background_style)]
+                line = [left, make_blank(width - 1, background_style)]
             elif border_right:
-                line = [Segment(" " * (width - 1), background_style), right]
+                line = [make_blank(width, background_style), right]
             else:
-                line = [Segment(" " * width, background_style)]
+                line = [make_blank(width, background_style)]
         else:
             # Content with border and padding (C)
             content_y = y - gutter.top
             if content_y < content_height:
                 line = render_content_line(y - gutter.top)
             else:
-                line = [Segment(" " * content_width, inner)]
+                line = [make_blank(content_width, inner)]
             if inner:
                 line = Segment.apply_style(line, inner)
             line = line_pad(line, pad_left, pad_right, inner)
diff --git a/src/textual/css/_style_properties.py b/src/textual/css/_style_properties.py
index 5770add70..15a1e8474 100644
--- a/src/textual/css/_style_properties.py
+++ b/src/textual/css/_style_properties.py
@@ -305,7 +305,7 @@ class BoxProperty:
             current_value: tuple[str, Color] = cast(
                 "tuple[str, Color]", obj.get_rule(self.name)
             )
-            has_edge = current_value and current_value[0]
+            has_edge = bool(current_value and current_value[0])
             new_edge = bool(_type)
             if obj.set_rule(self.name, new_value):
                 obj.refresh(layout=has_edge != new_edge)
diff --git a/src/textual/css/styles.py b/src/textual/css/styles.py
index c2bf84364..2fe674a47 100644
--- a/src/textual/css/styles.py
+++ b/src/textual/css/styles.py
@@ -594,8 +594,10 @@ class Styles(StylesBase):
         Returns:
             bool: ``True`` if a rule was cleared, or ``False`` if it was already not set.
         """
-        self._updates += 1
-        return self._rules.pop(rule, None) is not None
+        changed = self._rules.pop(rule, None) is not None
+        if changed:
+            self._updates += 1
+        return changed
 
     def get_rules(self) -> RulesMap:
         return self._rules.copy()
@@ -610,12 +612,17 @@ class Styles(StylesBase):
         Returns:
             bool: ``True`` if the rule changed, otherwise ``False``.
         """
-        self._updates += 1
         if value is None:
-            return self._rules.pop(rule, None) is not None
+            changed = self._rules.pop(rule, None) is not None
+            if changed:
+                self._updates += 1
+            return changed
         current = self._rules.get(rule)
         self._rules[rule] = value
-        return current != value
+        changed = current != value
+        if changed:
+            self._updates += 1
+        return changed
 
     def get_rule(self, rule: str, default: object = None) -> object:
         return self._rules.get(rule, default)

From 9dc3e13a3f91040576f28fc1c3581c9b47734c80 Mon Sep 17 00:00:00 2001
From: Will McGugan <willmcgugan@gmail.com>
Date: Thu, 24 Nov 2022 17:35:00 +0800
Subject: [PATCH 06/12] simplify refresh

---
 src/textual/_arrange.py     |  2 +-
 src/textual/_compositor.py  |  8 ++++----
 src/textual/_spatial_map.py | 27 +++++++++++++++++++++------
 src/textual/widget.py       | 10 ++++------
 4 files changed, 30 insertions(+), 17 deletions(-)

diff --git a/src/textual/_arrange.py b/src/textual/_arrange.py
index 2bf706e0f..102c17844 100644
--- a/src/textual/_arrange.py
+++ b/src/textual/_arrange.py
@@ -50,7 +50,7 @@ def arrange(
     get_dock = attrgetter("styles.dock")
     styles = widget.styles
 
-    for widgets in dock_layers.values():
+    for index, widgets in enumerate(dock_layers.values()):
 
         layout_widgets, dock_widgets = partition(get_dock, widgets)
 
diff --git a/src/textual/_compositor.py b/src/textual/_compositor.py
index 75dc2a51f..689e5b93c 100644
--- a/src/textual/_compositor.py
+++ b/src/textual/_compositor.py
@@ -388,16 +388,16 @@ class Compositor:
                         spatial_map.total_region.grow(spacing)
                     )
 
-                    placements = spatial_map.get_placements(
-                        child_region.reset_offset.translate(widget.scroll_offset)
-                    )
-
                     widgets.update(arranged_widgets)
 
                     # An offset added to all placements
                     placement_offset = container_region.offset + layout_offset
                     placement_scroll_offset = placement_offset - widget.scroll_offset
 
+                    placements = spatial_map.get_placements(
+                        (child_region.size.region).translate(widget.scroll_offset)
+                    )
+
                     _layers = widget.layers
                     layers_to_index = {
                         layer_name: index for index, layer_name in enumerate(_layers)
diff --git a/src/textual/_spatial_map.py b/src/textual/_spatial_map.py
index eb2685554..8f5d9879e 100644
--- a/src/textual/_spatial_map.py
+++ b/src/textual/_spatial_map.py
@@ -8,6 +8,7 @@ from typing import Iterable, Sequence
 from ._layout import WidgetPlacement
 from .geometry import Region, Spacing
 from ._partition import partition
+from ._profile import timer
 
 
 class SpatialMap:
@@ -27,8 +28,8 @@ class SpatialMap:
         self,
         placements: Sequence[WidgetPlacement],
         *,
-        block_width: int = 80,
-        block_height: int = 80,
+        block_width: int = 40,
+        block_height: int = 20,
     ) -> None:
         self._placements = placements
         self._total_region = Region()
@@ -39,8 +40,6 @@ class SpatialMap:
 
         self.placement_map = self._build_placements(placements)
 
-        print("SPATIAL", len(placements))
-
     def __iter__(self) -> Iterable[WidgetPlacement]:
         yield from self._placements
 
@@ -92,17 +91,24 @@ class SpatialMap:
         Returns:
             Iterable[WidgetPlacement]: A super-set of Widget placements that may be in the screen.
         """
+        return [
+            placement
+            for placement in self._placements
+            if screen_region.overlaps(placement.region)
+        ]
         x1, y1, width, height = screen_region
         x2 = x1 + width
         y2 = y1 + height
         block_width = self._block_width
         block_height = self._block_height
 
-        placements: set[WidgetPlacement] = set(self._fixed)
+        placements: set[WidgetPlacement] = set()
         extend_placements = placements.update
         map = self.placement_map
         map_get = map.get
 
+        overlaps_screen = screen_region.overlaps
+
         for coord in product(
             range(x1 // block_width, x2 // block_width + 1),
             range(y1 // block_height, y2 // block_height + 1),
@@ -111,4 +117,13 @@ class SpatialMap:
             if block_placements is not None:
                 extend_placements(block_placements)
 
-        return list(placements)
+        _placements = [
+            placement
+            for placement in self._placements
+            if placement in placements and not placement.fixed
+        ]
+
+        visible_placements = self._fixed + [
+            placement for placement in _placements if overlaps_screen(placement.region)
+        ]
+        return visible_placements
diff --git a/src/textual/widget.py b/src/textual/widget.py
index 292b670ba..275320558 100644
--- a/src/textual/widget.py
+++ b/src/textual/widget.py
@@ -759,14 +759,12 @@ class Widget(DOMNode):
     def watch_scroll_x(self, new_value: float) -> None:
         if self.show_horizontal_scrollbar:
             self.horizontal_scrollbar.position = int(new_value)
-            self.horizontal_scrollbar.refresh()
-            self.refresh(layout=True)
+            self.refresh(layout=True, repaint=False)
 
     def watch_scroll_y(self, new_value: float) -> None:
         if self.show_vertical_scrollbar:
             self.vertical_scrollbar.position = int(new_value)
-            self.vertical_scrollbar.refresh()
-            self.refresh(layout=True)
+            self.refresh(layout=True, repaint=False)
 
     def validate_scroll_x(self, value: float) -> float:
         return clamp(value, 0, self.max_scroll_x)
@@ -2134,12 +2132,12 @@ class Widget(DOMNode):
             layout (bool, optional): Also layout widgets in the view. Defaults to False.
         """
 
-        if layout:
+        if layout and not self._layout_required:
             self._layout_required = True
             if isinstance(self._parent, Widget):
                 self._parent._clear_arrangement_cache()
 
-        if repaint:
+        if repaint and not self._repaint_required:
             self._set_dirty(*regions)
             self._content_width_cache = (None, 0)
             self._content_height_cache = (None, 0)

From 935020101d719c1821e15c94817d1f35c6017881 Mon Sep 17 00:00:00 2001
From: Will McGugan <willmcgugan@gmail.com>
Date: Thu, 24 Nov 2022 17:41:24 +0800
Subject: [PATCH 07/12] remove spatial map

---
 src/textual/_arrange.py     |   2 +-
 src/textual/_compositor.py  |  16 ++---
 src/textual/_layout.py      |   3 +-
 src/textual/_spatial_map.py | 129 ------------------------------------
 src/textual/widget.py       |   3 +-
 5 files changed, 10 insertions(+), 143 deletions(-)
 delete mode 100644 src/textual/_spatial_map.py

diff --git a/src/textual/_arrange.py b/src/textual/_arrange.py
index 102c17844..2bf706e0f 100644
--- a/src/textual/_arrange.py
+++ b/src/textual/_arrange.py
@@ -50,7 +50,7 @@ def arrange(
     get_dock = attrgetter("styles.dock")
     styles = widget.styles
 
-    for index, widgets in enumerate(dock_layers.values()):
+    for widgets in dock_layers.values():
 
         layout_widgets, dock_widgets = partition(get_dock, widgets)
 
diff --git a/src/textual/_compositor.py b/src/textual/_compositor.py
index 689e5b93c..d6fd0403c 100644
--- a/src/textual/_compositor.py
+++ b/src/textual/_compositor.py
@@ -381,12 +381,9 @@ class Compositor:
 
                 if widget.is_container:
                     # Arrange the layout
-                    spatial_map, arranged_widgets, spacing = widget._arrange(
+                    placements, arranged_widgets, spacing = widget._arrange(
                         child_region.size
                     )
-                    total_region = total_region.union(
-                        spatial_map.total_region.grow(spacing)
-                    )
 
                     widgets.update(arranged_widgets)
 
@@ -394,10 +391,6 @@ class Compositor:
                     placement_offset = container_region.offset + layout_offset
                     placement_scroll_offset = placement_offset - widget.scroll_offset
 
-                    placements = spatial_map.get_placements(
-                        (child_region.size.region).translate(widget.scroll_offset)
-                    )
-
                     _layers = widget.layers
                     layers_to_index = {
                         layer_name: index for index, layer_name in enumerate(_layers)
@@ -405,11 +398,16 @@ class Compositor:
                     get_layer_index = layers_to_index.get
 
                     # Add all the widgets
-                    for sub_region, _, sub_widget, z, fixed in reversed(placements):
+                    for sub_region, margin, sub_widget, z, fixed in reversed(
+                        placements
+                    ):
                         # Combine regions with children to calculate the "virtual size"
                         if fixed:
                             widget_region = sub_region + placement_offset
                         else:
+                            total_region = total_region.union(
+                                sub_region.grow(spacing + margin)
+                            )
                             widget_region = sub_region + placement_scroll_offset
 
                         widget_order = order + (
diff --git a/src/textual/_layout.py b/src/textual/_layout.py
index 25d2d27c7..a87061b36 100644
--- a/src/textual/_layout.py
+++ b/src/textual/_layout.py
@@ -8,10 +8,9 @@ from ._typing import TypeAlias
 
 if TYPE_CHECKING:
     from .widget import Widget
-    from ._spatial_map import SpatialMap
 
 ArrangeResult: TypeAlias = "tuple[list[WidgetPlacement], set[Widget]]"
-DockArrangeResult: TypeAlias = "SpacialMap, set[Widget], Spacing]"
+DockArrangeResult: TypeAlias = "list[WidgetPlacement], set[Widget], Spacing]"
 
 
 class WidgetPlacement(NamedTuple):
diff --git a/src/textual/_spatial_map.py b/src/textual/_spatial_map.py
deleted file mode 100644
index 8f5d9879e..000000000
--- a/src/textual/_spatial_map.py
+++ /dev/null
@@ -1,129 +0,0 @@
-from __future__ import annotations
-
-from collections import defaultdict
-from itertools import product
-from operator import attrgetter
-from typing import Iterable, Sequence
-
-from ._layout import WidgetPlacement
-from .geometry import Region, Spacing
-from ._partition import partition
-from ._profile import timer
-
-
-class SpatialMap:
-    """An object to return WidgetPlacements within a given region.
-
-    The widget area is split in to a regular grid of buckets. Each placement is assigned to
-    any bucket it overlaps, which may be 1 or more buckets.
-
-    The `get_placements` function will calculate which buckets overlap the screen area, and combine
-    the placements from those buckets. This generally means that widgets that aren't overlapping or
-    near the screen area can be quickly discarded. The result will typically be a superset of visible
-    placements, which can then be filtered normally.
-
-    """
-
-    def __init__(
-        self,
-        placements: Sequence[WidgetPlacement],
-        *,
-        block_width: int = 40,
-        block_height: int = 20,
-    ) -> None:
-        self._placements = placements
-        self._total_region = Region()
-        self._block_width = block_width
-        self._block_height = block_height
-        self._fixed: list[WidgetPlacement] = []
-        self._map: defaultdict[tuple[int, int], list[WidgetPlacement]] | None = None
-
-        self.placement_map = self._build_placements(placements)
-
-    def __iter__(self) -> Iterable[WidgetPlacement]:
-        yield from self._placements
-
-    def __reversed__(self) -> Iterable[WidgetPlacement]:
-        yield from reversed(self._placements)
-
-    def _build_placements(
-        self, placements: Iterable[WidgetPlacement]
-    ) -> defaultdict[tuple[int, int], list[WidgetPlacement]]:
-        """Add placements to map.
-
-        Args:
-            placements (Iterable[WidgetPlacement]): A number of placements.
-        """
-        map: defaultdict[tuple[int, int], list[WidgetPlacement]] = defaultdict(list)
-        get_bucket = map.__getitem__
-
-        block_width = self._block_width
-        block_height = self._block_height
-
-        self.total_region = Region.from_union(
-            [
-                placement.region.grow(placement.margin)
-                for placement in placements
-                if not placement.fixed
-            ]
-        )
-
-        placements, self._fixed = partition(attrgetter("fixed"), placements)
-
-        for placement in placements:
-            x1, y1, width, height = placement.region
-            x2 = x1 + width
-            y2 = y1 + height
-            for coord in product(
-                range(x1 // block_width, x2 // block_width + 1),
-                range(y1 // block_height, y2 // block_height + 1),
-            ):
-                get_bucket(coord).append(placement)
-        return map
-
-    def get_placements(self, screen_region: Region) -> list[WidgetPlacement]:
-        """Get placements that may overlap a given region. There may be false positives,
-        but no false negatives.
-
-        Args:
-            region (Region): Container region.
-
-        Returns:
-            Iterable[WidgetPlacement]: A super-set of Widget placements that may be in the screen.
-        """
-        return [
-            placement
-            for placement in self._placements
-            if screen_region.overlaps(placement.region)
-        ]
-        x1, y1, width, height = screen_region
-        x2 = x1 + width
-        y2 = y1 + height
-        block_width = self._block_width
-        block_height = self._block_height
-
-        placements: set[WidgetPlacement] = set()
-        extend_placements = placements.update
-        map = self.placement_map
-        map_get = map.get
-
-        overlaps_screen = screen_region.overlaps
-
-        for coord in product(
-            range(x1 // block_width, x2 // block_width + 1),
-            range(y1 // block_height, y2 // block_height + 1),
-        ):
-            block_placements = map_get(coord)
-            if block_placements is not None:
-                extend_placements(block_placements)
-
-        _placements = [
-            placement
-            for placement in self._placements
-            if placement in placements and not placement.fixed
-        ]
-
-        visible_placements = self._fixed + [
-            placement for placement in _placements if overlaps_screen(placement.region)
-        ]
-        return visible_placements
diff --git a/src/textual/widget.py b/src/textual/widget.py
index 275320558..4f9ce86b4 100644
--- a/src/textual/widget.py
+++ b/src/textual/widget.py
@@ -39,7 +39,6 @@ from ._context import active_app
 from ._easing import DEFAULT_SCROLL_EASING
 from ._layout import Layout
 from ._segment_tools import align_lines
-from ._spatial_map import SpatialMap
 from ._styles_cache import StylesCache
 from ._types import Lines
 from .await_remove import AwaitRemove
@@ -429,7 +428,7 @@ class Widget(DOMNode):
         placements, widgets, spacing = arrange(
             self, self.children, size, self.screen.size
         )
-        arrange_result = SpatialMap(placements), widgets, spacing
+        arrange_result = placements, widgets, spacing
         self._arrangement = arrange_result
         return self._arrangement
 

From 40dbffc46c988db13c2f232aff596f0191167726 Mon Sep 17 00:00:00 2001
From: Will McGugan <willmcgugan@gmail.com>
Date: Thu, 24 Nov 2022 17:42:07 +0800
Subject: [PATCH 08/12] Ws

---
 src/textual/_compositor.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/textual/_compositor.py b/src/textual/_compositor.py
index d6fd0403c..ab9d69eca 100644
--- a/src/textual/_compositor.py
+++ b/src/textual/_compositor.py
@@ -384,7 +384,6 @@ class Compositor:
                     placements, arranged_widgets, spacing = widget._arrange(
                         child_region.size
                     )
-
                     widgets.update(arranged_widgets)
 
                     # An offset added to all placements

From ce0773885fa674fbd44bdc12fed65f9b4a3cd4ef Mon Sep 17 00:00:00 2001
From: Will McGugan <willmcgugan@gmail.com>
Date: Thu, 24 Nov 2022 17:42:57 +0800
Subject: [PATCH 09/12] fix alias

---
 src/textual/_layout.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/textual/_layout.py b/src/textual/_layout.py
index a87061b36..ca5233104 100644
--- a/src/textual/_layout.py
+++ b/src/textual/_layout.py
@@ -10,7 +10,7 @@ if TYPE_CHECKING:
     from .widget import Widget
 
 ArrangeResult: TypeAlias = "tuple[list[WidgetPlacement], set[Widget]]"
-DockArrangeResult: TypeAlias = "list[WidgetPlacement], set[Widget], Spacing]"
+DockArrangeResult: TypeAlias = "tuple[list[WidgetPlacement], set[Widget], Spacing]]"
 
 
 class WidgetPlacement(NamedTuple):

From 84f24d947b879279f325834001a55274e47d8b16 Mon Sep 17 00:00:00 2001
From: Will McGugan <willmcgugan@gmail.com>
Date: Thu, 24 Nov 2022 17:44:16 +0800
Subject: [PATCH 10/12] restore arrangement

---
 src/textual/widget.py | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/src/textual/widget.py b/src/textual/widget.py
index 4f9ce86b4..acdac6a9f 100644
--- a/src/textual/widget.py
+++ b/src/textual/widget.py
@@ -425,11 +425,7 @@ class Widget(DOMNode):
             return self._arrangement
 
         self._arrangement_cache_key = arrange_cache_key
-        placements, widgets, spacing = arrange(
-            self, self.children, size, self.screen.size
-        )
-        arrange_result = placements, widgets, spacing
-        self._arrangement = arrange_result
+        self._arrangement = arrange(self, self.children, size, self.screen.size)
         return self._arrangement
 
     def _clear_arrangement_cache(self) -> None:

From 4057744c8848176d83264d7a5812ef7d806c1d2d Mon Sep 17 00:00:00 2001
From: Will McGugan <willmcgugan@gmail.com>
Date: Thu, 24 Nov 2022 17:49:22 +0800
Subject: [PATCH 11/12] fix blank

---
 src/textual/_styles_cache.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/textual/_styles_cache.py b/src/textual/_styles_cache.py
index f3b738cce..d502a9a60 100644
--- a/src/textual/_styles_cache.py
+++ b/src/textual/_styles_cache.py
@@ -339,7 +339,7 @@ class StylesCache:
             elif border_left:
                 line = [left, make_blank(width - 1, background_style)]
             elif border_right:
-                line = [make_blank(width, background_style), right]
+                line = [make_blank(width - 1, background_style), right]
             else:
                 line = [make_blank(width, background_style)]
         else:

From edf716b5086aaf023f37c480e7bdc1a6b295f196 Mon Sep 17 00:00:00 2001
From: Will McGugan <willmcgugan@gmail.com>
Date: Thu, 24 Nov 2022 17:55:14 +0800
Subject: [PATCH 12/12] fix updates

---
 src/textual/widget.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/textual/widget.py b/src/textual/widget.py
index acdac6a9f..70a3b353a 100644
--- a/src/textual/widget.py
+++ b/src/textual/widget.py
@@ -2127,12 +2127,12 @@ class Widget(DOMNode):
             layout (bool, optional): Also layout widgets in the view. Defaults to False.
         """
 
-        if layout and not self._layout_required:
+        if layout:
             self._layout_required = True
             if isinstance(self._parent, Widget):
                 self._parent._clear_arrangement_cache()
 
-        if repaint and not self._repaint_required:
+        if repaint:
             self._set_dirty(*regions)
             self._content_width_cache = (None, 0)
             self._content_height_cache = (None, 0)