content simplify

src/textual/_compositor.py

@@ -614,6 +614,7 @@ class Compositor:
                             )
                         )
                         widget.set_reactive(Widget.scroll_y, new_scroll_y)
+                        widget.set_reactive(Widget.scroll_target_y, new_scroll_y)
                         widget.vertical_scrollbar._reactive_position = new_scroll_y
 
                     if visible_only:

src/textual/_slug.py

@@ -114,3 +114,30 @@ class TrackedSlugs:
         if used:
             slugged = f"{slugged}-{used}"
         return slugged
+
+
+VALID_ID_CHARACTERS = frozenset("abcdefghijklmnopqrstuvwxyz0123456789-")
+
+
+def slug_for_tcss_id(text: str) -> str:
+    """Produce a slug usable as a TCSS id from the given text.
+
+    Args:
+        text: Text.
+
+    Returns:
+        A slugified version of text suitable for use as a TCSS id.
+    """
+    slug = "".join(
+        (
+            character
+            if character in VALID_ID_CHARACTERS
+            else ord(character).__format__("x")
+        )
+        for character in text
+    )
+    if not slug:
+        return "-"
+    if slug[0].isdecimal():
+        return f"-{slug}"
+    return slug

src/textual/content.py

@@ -395,6 +395,34 @@ class Content(Visual):
             text_append(end)
         return cls("".join(text), spans)
 
+    def simplify(self) -> Content:
+        """Simplify spans in place.
+
+        This joins contiguous spans together which can produce faster renders.
+
+        Note that this is only typically worth it if you have appended a large number of Content instances together,
+        and it only needs to be done once.
+
+        Returns:
+            Self.
+        """
+        spans = self.spans
+        if not spans:
+            return self
+        last_span = Span(0, 0, Style())
+        new_spans: list[Span] = []
+        changed: bool = False
+        for span in self._spans:
+            if span.start == last_span.end and span.style == last_span.style:
+                last_span = new_spans[-1] = Span(last_span.start, span.end, span.style)
+                changed = True
+            else:
+                new_spans.append(span)
+                last_span = span
+        if changed:
+            self._spans[:] = new_spans
+        return self
+
     def __eq__(self, other: object) -> bool:
         """Compares text only, so that markup doesn't effect sorting."""
         if isinstance(other, str):
@@ -528,7 +556,6 @@ class Content(Visual):
                 return None
 
         for y, line in enumerate(self.split(allow_blank=True)):
-
             if post_style is not None:
                 line = line.stylize(post_style)
 
@@ -1201,6 +1228,11 @@ class Content(Visual):
         ]
         return segments
 
+    def __rich__(self):
+        from rich.segment import Segments
+
+        return Segments(self.render_segments(Style(), "\n"))
+
     def _divide_spans(self, offsets: tuple[int, ...]) -> list[tuple[Span, int, int]]:
         """Divide content from a list of offset to cut.
 
@@ -1568,7 +1600,6 @@ class _FormattedLine:
     def _apply_link_style(
         self, link_style: RichStyle, segments: list[Segment]
     ) -> list[Segment]:
-
         _Segment = Segment
         segments = [
             _Segment(

src/textual/getters.py

@@ -5,12 +5,37 @@ Descriptors to define properties on your widget, screen, or App.
 
 from __future__ import annotations
 
-from typing import Generic, overload
+from typing import Generic, TypeVar, overload
 
 from textual.css.query import NoMatches, QueryType, WrongType
 from textual.dom import DOMNode
 from textual.widget import Widget
 
+AppType = TypeVar("AppType", bound="App")
+
+
+class app(Generic[AppType]):
+    """A typed getter for the app.
+
+    Example:
+        ```python
+        class MyWidget(Widget):
+            app = getters.app(MyApp)
+        ```
+
+
+    Args:
+        Generic (_type_): _description_
+    """
+
+    def __init__(self, app_type: type[AppType]) -> None:
+        self._app_type = app_type
+
+    def __get__(self, obj: DOMNode, obj_type: type[DOMNode]) -> AppType:
+        app = obj.app
+        assert isinstance(app, self._app_type)
+        return app
+
 
 class query_one(Generic[QueryType]):
     """Create a query one property.

src/textual/visual.py

@@ -196,6 +196,7 @@ class Visual(ABC):
         height: int | None,
         style: Style,
         *,
+        apply_selection: bool = True,
         pad: bool = False,
         post_style: Style | None = None,
     ) -> list[Strip]:
@@ -207,6 +208,7 @@ class Visual(ABC):
             width: Desired width (in cells).
             height: Desired height (in lines) or `None` for no limit.
             style: A (Visual) Style instance.
+            apply_selection: Automatically apply selection styles?
             pad: Pad to desired width?
             post_style: Optional Style to apply to strips after rendering.
 
@@ -229,7 +231,7 @@ class Visual(ABC):
             RenderOptions(
                 widget._get_style,
                 widget.styles,
-                selection,
+                selection if apply_selection else None,
                 selection_style,
             ),
         )

src/textual/widgets/_markdown.py

@@ -13,7 +13,7 @@ from markdown_it.token import Token
 from rich.text import Text
 from typing_extensions import TypeAlias
 
-from textual._slug import TrackedSlugs, slug
+from textual._slug import TrackedSlugs, slug_for_tcss_id
 from textual.app import ComposeResult
 from textual.await_complete import AwaitComplete
 from textual.containers import Horizontal, Vertical, VerticalScroll
@@ -1271,7 +1271,9 @@ class Markdown(Widget):
             elif token_type.endswith("_close"):
                 block = stack.pop()
                 if token.type == "heading_close":
-                    block.id = f"heading-{slug(block._content.plain)}-{id(block)}"
+                    block.id = (
+                        f"heading-{slug_for_tcss_id(block._content.plain)}-{id(block)}"
+                    )
                 if stack:
                     stack[-1]._blocks.append(block)
                 else:

tests/test_slug.py

@@ -1,6 +1,6 @@
 import pytest
 
-from textual._slug import TrackedSlugs, slug
+from textual._slug import TrackedSlugs, slug_for_tcss_id
 
 
 @pytest.mark.xdist_group("group1")
@@ -31,7 +31,7 @@ from textual._slug import TrackedSlugs, slug
 )
 def test_simple_slug(text: str, expected: str) -> None:
     """The simple slug function should produce the expected slug."""
-    assert slug(text) == expected
+    assert slug_for_tcss_id(text) == expected
 
 
 @pytest.fixture(scope="module")