Merge pull request #221 from Textualize/dont-render-margin

Margin spacing is now invisible

src/textual/css/_styles_builder.py

@@ -129,7 +129,7 @@ class StylesBuilder:
         append = space.append
         for token in tokens:
             (token_name, value, _, _, location) = token
-            if token_name == "scalar":
+            if token_name in ("number", "scalar"):
                 try:
                     append(int(value))
                 except ValueError:

src/textual/geometry.py

@@ -415,6 +415,25 @@ class Region(NamedTuple):
         )
         return new_region
 
+    def shrink(self, margin: Spacing) -> Region:
+        """Shrink a region by pushing each edge inwards.
+
+        Args:
+            margin (Spacing): Defines how many cells to shrink the Region by at each edge.
+
+        Returns:
+            Region: The new, smaller region.
+        """
+        _clamp = clamp
+        top, right, bottom, left = margin
+        x, y, width, height = self
+        return Region(
+            x=_clamp(x + left, 0, width),
+            y=_clamp(y + top, 0, height),
+            width=_clamp(width - left - right, 0, width),
+            height=_clamp(height - top - bottom, 0, height),
+        )
+
     def intersection(self, region: Region) -> Region:
         """Get that covers both regions.
 

src/textual/layout.py

@@ -55,6 +55,17 @@ class WidgetPlacement(NamedTuple):
     widget: Widget | None = None
     order: int = 0
 
+    def apply_margin(self) -> "WidgetPlacement":
+        region, widget, order = self
+        styles = widget.styles
+        if styles.has_margin:
+            return WidgetPlacement(
+                region=region.shrink(styles.margin),
+                widget=widget,
+                order=order,
+            )
+        return self
+
 
 @rich.repr.auto
 class LayoutUpdate:

src/textual/view.py

@@ -102,9 +102,14 @@ class View(Widget):
         cached_size, cached_scroll, arrangement = self._cached_arrangement
         if cached_size == size and cached_scroll == scroll:
             return arrangement
-        arrangement = list(self.layout.arrange(self, size, scroll))
-        self._cached_arrangement = (size, scroll, arrangement)
-        return arrangement
+
+        placements = [
+            placement.apply_margin()
+            for placement in self._layout.arrange(self, size, scroll)
+        ]
+
+        self._cached_arrangement = (size, scroll, placements)
+        return placements
 
     async def handle_update(self, message: messages.Update) -> None:
         if self.is_root_view:

src/textual/widget.py

@@ -170,9 +170,6 @@ class Widget(DOMNode):
         if styles.has_border:
             renderable = Border(renderable, styles.border, style=renderable_text_style)
 
-        if styles.has_margin:
-            renderable = Padding(renderable, styles.margin, style=parent_text_style)
-
         if styles.has_outline:
             renderable = Border(
                 renderable,

tests/test_geometry.py

@@ -1,6 +1,6 @@
 import pytest
 
-from textual.geometry import clamp, Offset, Size, Region
+from textual.geometry import clamp, Offset, Size, Region, Spacing
 
 
 def test_dimensions_region():
@@ -173,6 +173,12 @@ def test_clip():
     assert Region(10, 10, 20, 30).clip(20, 25) == Region(10, 10, 10, 15)
 
 
+def test_region_shrink():
+    margin = Spacing(top=1, right=2, bottom=3, left=4)
+    region = Region(x=10, y=10, width=50, height=50)
+    assert region.shrink(margin) == Region(x=14, y=11, width=44, height=46)
+
+
 def test_region_intersection():
     assert Region(0, 0, 100, 50).intersection(Region(10, 10, 10, 10)) == Region(
         10, 10, 10, 10