Merge pull request #212 from Textualize/visibility

Visibility

examples/basic.css

@@ -2,6 +2,7 @@
 
 App > View {
   docks: side=left/1;
+  text: on #20639b;
 }
 
 Widget:hover {
@@ -28,6 +29,10 @@ Widget:hover {
   border: hkey;
 }
 
+#header.-visible {
+  visibility: hidden;
+}
+
 #content {
   text: white on #20639b;
   border-bottom: hkey #0f2b41;

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', '-visible')")
 
     def on_mount(self):
         """Build layout here."""

src/textual/blank.py

@@ -0,0 +1,32 @@
+from __future__ import annotations
+
+from rich.console import Console, ConsoleOptions
+from rich.segment import Segment
+from rich.style import StyleType
+
+
+class Blank:
+    """
+    Render an empty rectangle.
+
+    Args:
+        style (StyleType): Style to apply to the box.
+        width (int, optional): Width of the box in number of cells. Will expand to fit parent if ``None``.
+        height (int, optional): Height of the box in number of cells. Will expand to fit parent if ``None``.
+    """
+
+    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/css/styles.py

@@ -235,6 +235,13 @@ class Styles:
         else:
             return None
 
+    def reset(self) -> None:
+        """
+        Reset internal style rules to ``None``, reverting to default styles.
+        """
+        for rule_name in INTERNAL_RULE_NAMES:
+            setattr(self, rule_name, None)
+
     def extract_rules(
         self, specificity: Specificity3
     ) -> list[tuple[str, Specificity4, Any]]:

src/textual/css/stylesheet.py

@@ -113,8 +113,14 @@ class Stylesheet:
         rule_attributes = defaultdict(list)
 
         _check_rule = self._check_rule
+
+        node.styles.reset()
+
+        # Get the default node CSS rules
         for key, default_specificity, value in node._default_rules:
             rule_attributes[key].append((default_specificity, value))
+
+        # Apply styles on top of the default node CSS rules
         for rule in self.rules:
             for specificity in _check_rule(rule, node):
                 for key, rule_specificity, value in rule.styles.extract_rules(
@@ -123,13 +129,6 @@ class Stylesheet:
                     rule_attributes[key].append((rule_specificity, value))
 
         get_first_item = itemgetter(0)
-
-        log("")
-        log(node)
-        for key, attributes in rule_attributes.items():
-            log(key, key in node.styles.important)
-            log("\t", attributes)
-
         node_rules = [
             (name, max(specificity_rules, key=get_first_item)[1])
             for name, specificity_rules in rule_attributes.items()

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 +161,36 @@ 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
 

tests/test_styles.py

@@ -0,0 +1,11 @@
+from rich.style import Style
+
+from textual.css.styles import Styles
+
+
+def test_styles_reset():
+    styles = Styles()
+    styles.text_style = "not bold"
+    assert styles.text_style == Style(bold=False)
+    styles.reset()
+    assert styles.text_style is Style.null()