new border renderable includes outline

src/textual/_border.py

@@ -14,25 +14,55 @@ class Border:
         self,
         renderable: RenderableType,
         edge_styles: tuple[EdgeStyle, EdgeStyle, EdgeStyle, EdgeStyle],
+        outline: bool = False,
     ):
         self.renderable = renderable
         self.edge_styles = edge_styles
+        self.outline = outline
 
-    @property
+        (
-    def sides(self) -> tuple[str, str, str, str]:
+            (top, top_style),
-        (top, _), (right, _), (bottom, _), (left, _) = self.edge_styles
+            (right, right_style),
-        return (top or "none", right or "none", bottom or "none", left or "none")
+            (bottom, bottom_style),
+            (left, left_style),
+        ) = edge_styles
+        self._sides = (top or "none", right or "none", bottom or "none", left or "none")
+        self._styles = (top_style, right_style, bottom_style, left_style)
 
-    @property
+    def _crop_renderable(self, lines: list[list[Segment]], width: int) -> None:
-    def styles(self) -> tuple[Style, Style, Style, Style]:
+        """Crops a renderable in place.
-        (_, top), (_, right), (_, left), (_, bottom) = self.edge_styles
+
-        return (top, right, left, bottom)
+        Args:
+            lines (list[list[Segment]]): Segment lines.
+            width (int): Desired width.
+        """
+        top, right, bottom, left = self._sides
+        has_left = left != "none"
+        has_right = right != "none"
+        has_top = top != "none"
+        has_bottom = bottom != "none"
+
+        if has_top:
+            lines.pop(0)
+        if has_bottom:
+            lines.pop(-1)
+
+        divide = Segment.divide
+        if has_left and has_right:
+            for line in lines:
+                _, line[:] = divide(line, [1, width - 1])
+        elif has_left:
+            for line in lines:
+                _, line[:] = divide(line, [1, width])
+        elif has_right:
+            for line in lines:
+                line[:], _ = divide(line, [width - 1, width])
 
     def __rich_console__(
         self, console: "Console", options: "ConsoleOptions"
     ) -> "RenderResult":
-        top, right, bottom, left = self.sides
+        top, right, bottom, left = self._sides
-        top_style, right_style, bottom_style, left_style = self.styles
+        top_style, right_style, bottom_style, left_style = self._styles
         BOX = BOX_STYLES
 
         has_left = left != "none"
@@ -41,13 +71,18 @@ class Border:
         has_bottom = bottom != "none"
 
         width = options.max_width - has_left - has_right
-        if options.height is None:
+        if self.outline:
-            render_options = options.update_width(width)
+            render_options = options
         else:
-            height = options.height - has_top - has_bottom
+            if options.height is None:
-            render_options = options.update_dimensions(width, height)
+                render_options = options.update_width(width)
+            else:
+                height = options.height - has_top - has_bottom
+                render_options = options.update_dimensions(width, height)
 
         lines = console.render_lines(self.renderable, render_options)
+        if self.outline:
+            self._crop_renderable(lines, options.max_width)
 
         _Segment = Segment
         new_line = _Segment.line()
@@ -63,13 +98,12 @@ class Border:
         box_left = BOX[left][1][0]
         box_right = BOX[right][1][2]
         left_segment = _Segment(box_left, left_style)
-        right_segment = _Segment(box_right, right_style)
+        right_segment = _Segment(box_right + "\n", right_style)
         if has_left and has_right:
             for line in lines:
                 yield left_segment
                 yield from line
                 yield right_segment
-                yield new_line
         elif has_left:
             for line in lines:
                 yield left_segment
@@ -79,7 +113,6 @@ class Border:
             for line in lines:
                 yield from line
                 yield right_segment
-                yield new_line
         else:
             for line in lines:
                 yield from line
@@ -100,14 +133,18 @@ if __name__ == "__main__":
     from rich.text import Text
 
     text = Text("Textual " * 40, style="dim")
-    print(
+    border = Border(
-        Border(
+        text,
-            text,
+        (
-            (
+            ("outer", Style.parse("green")),
-                ("outer", Style.parse("green on red")),
+            ("outer", Style.parse("green")),
-                ("none", Style.parse("green")),
+            ("outer", Style.parse("green")),
-                ("double", Style.parse("green")),
+            ("outer", Style.parse("green")),
-                ("double", Style.parse("green")),
+        ),
-            ),
-        )
     )
+    print(text)
+    print()
+    print(border)
+    print()
+    border.outline = True
+    print(border)