Initial implementation of visibility

examples/basic.py

@@ -8,6 +8,7 @@ class BasicApp(App):
     def on_load(self):
         """Bind keys here."""
         self.bind("tab", "toggle_class('#sidebar', '-active')")
+        self.bind("a", "toggle_class('#header', '-no-header')")
 
     def on_mount(self):
         """Build layout here."""

src/textual/blank.py

@@ -0,0 +1,19 @@
+from __future__ import annotations
+
+from rich.console import Console, ConsoleOptions
+from rich.segment import Segment
+from rich.style import StyleType
+
+
+class Blank:
+    def __init__(self, style: StyleType, width: int | None = None, height: int | None = None):
+        self.style = style
+        self.width = width
+        self.height = height
+
+    def __rich_console__(self, console: Console, console_options: ConsoleOptions):
+        render_width = self.width or console_options.max_width
+        render_height = self.height or console_options.height or console_options.max_height
+        style = console.get_style(self.style)
+        for _ in range(render_height):
+            yield Segment(" " * render_width + "\n", style)

src/textual/widget.py

@@ -14,11 +14,13 @@ from typing import (
 import rich.repr
 from rich import box
 from rich.align import Align
-from rich.console import Console, RenderableType
+from rich.console import Console, RenderableType, ConsoleOptions
+from rich.measure import Measurement
 from rich.panel import Panel
 from rich.padding import Padding
 from rich.pretty import Pretty
-from rich.style import Style
+from rich.segment import Segment
+from rich.style import Style, StyleType
 from rich.styled import Styled
 from rich.text import Text, TextType
 
@@ -27,6 +29,7 @@ from . import errors
 from ._animator import BoundAnimator
 from ._border import Border, BORDER_STYLES
 from ._callback import invoke
+from .blank import Blank
 from .dom import DOMNode
 from ._context import active_app
 from .geometry import Size, Spacing, SpacingDimensions
@@ -158,28 +161,31 @@ class Widget(DOMNode):
 
         renderable = self.render()
         styles = self.styles
-
         parent_text_style = self.parent.text_style
-        text_style = styles.text
-        renderable_text_style = parent_text_style + text_style
-        if renderable_text_style:
-            renderable = Styled(renderable, renderable_text_style)
 
-        if styles.has_padding:
-            renderable = Padding(
-                renderable, styles.padding, style=renderable_text_style
-            )
+        if styles.visibility == "hidden":
+            renderable = Blank(parent_text_style)
+        else:
+            text_style = styles.text
+            renderable_text_style = parent_text_style + text_style
+            if renderable_text_style:
+                renderable = Styled(renderable, renderable_text_style)
 
-        if styles.has_border:
-            renderable = Border(renderable, styles.border, style=renderable_text_style)
+            if styles.has_padding:
+                renderable = Padding(
+                    renderable, styles.padding, style=renderable_text_style
+                )
 
-        if styles.has_margin:
-            renderable = Padding(renderable, styles.margin, style=parent_text_style)
+            if styles.has_border:
+                renderable = Border(renderable, styles.border, style=renderable_text_style)
 
-        if styles.has_outline:
-            renderable = Border(
-                renderable, styles.outline, outline=True, style=renderable_text_style
-            )
+            if styles.has_margin:
+                renderable = Padding(renderable, styles.margin, style=parent_text_style)
+
+            if styles.has_outline:
+                renderable = Border(
+                    renderable, styles.outline, outline=True, style=renderable_text_style
+                )
 
         return renderable