Batch update

CHANGELOG.md

@@ -7,9 +7,15 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [0.12.0] - Unreleased
 
+### Added
+
+- Added `App.batch_update` https://github.com/Textualize/textual/pull/1832
+- Added horizontal rule to Markdown https://github.com/Textualize/textual/pull/1832
+
 ### Changed
 
 - Scrolling by page now adds to current position.
+- Markdown lists have been polished: a selection of bullets, better alignment of numbers, style tweaks https://github.com/Textualize/textual/pull/1832
 
 ### Removed
 

examples/dictionary.css

@@ -8,9 +8,9 @@ Input {
 }
 
 #results {
-    width: auto;   
-    min-height: 100%;
-    padding: 0 1;    
+    width: 100%;
+    height: auto;
+
 }
 
 #results-container {

examples/dictionary.py

@@ -7,11 +7,10 @@
 except ImportError:
     raise ImportError("Please install httpx with 'pip install httpx' ")
 
-from rich.markdown import Markdown
 
 from textual.app import App, ComposeResult
 from textual.containers import Content
-from textual.widgets import Input, Static
+from textual.widgets import Input, Markdown
 
 
 class DictionaryApp(App):
@@ -21,7 +20,7 @@ class DictionaryApp(App):
 
     def compose(self) -> ComposeResult:
         yield Input(placeholder="Search for a word")
-        yield Content(Static(id="results"), id="results-container")
+        yield Content(Markdown(id="results"), id="results-container")
 
     def on_mount(self) -> None:
         """Called when app starts."""
@@ -35,7 +34,7 @@ async def on_input_changed(self, message: Input.Changed) -> None:
             asyncio.create_task(self.lookup_word(message.value))
         else:
             # Clear the results
-            self.query_one("#results", Static).update()
+            await self.query_one("#results", Markdown).update("")
 
     async def lookup_word(self, word: str) -> None:
         """Looks up a word."""
@@ -50,7 +49,7 @@ async def lookup_word(self, word: str) -> None:
 
         if word == self.query_one(Input).value:
             markdown = self.make_word_markdown(results)
-            self.query_one("#results", Static).update(Markdown(markdown))
+            await self.query_one("#results", Markdown).update(markdown)
 
     def make_word_markdown(self, results: object) -> str:
         """Convert the results in to markdown."""

examples/example.md

@@ -42,6 +42,32 @@ Two tildes indicates strikethrough, e.g. `~~cross out~~` render ~~cross out~~.
 
 Inline code is indicated by backticks. e.g. `import this`.
 
+## Lists
+
+1. Lists can be ordered
+2. Lists can be unordered
+   - I must not fear.
+     - Fear is the mind-killer.
+       - Fear is the little-death that brings total obliteration.
+         - I will face my fear.
+           - I will permit it to pass over me and through me.
+     - And when it has gone past, I will turn the inner eye to see its path.
+   - Where the fear has gone there will be nothing. Only I will remain.
+
+### Longer list
+
+1. **Duke Leto I Atreides**, head of House Atreides
+2. **Lady Jessica**, Bene Gesserit and concubine of Leto, and mother of Paul and Alia
+3. **Paul Atreides**, son of Leto and Jessica
+4. **Alia Atreides**, daughter of Leto and Jessica
+5. **Gurney Halleck**, troubadour warrior of House Atreides
+6. **Thufir Hawat**, Mentat and Master of Assassins of House Atreides
+7. **Duncan Idaho**, swordmaster of House Atreides
+8. **Dr. Wellington Yueh**, Suk doctor of House Atreides
+9. **Leto**, first son of Paul and Chani who dies as a toddler
+10. **Esmar Tuek**, a smuggler on Arrakis
+11. **Staban Tuek**, son of Esmar
+
 ## Fences
 
 Fenced code blocks are introduced with three back-ticks and the optional parser. Here we are rendering the code in a sub-widget with syntax highlighting and indent guides.

src/textual/app.py

@@ -11,7 +11,12 @@
 import warnings
 from asyncio import Task
 from concurrent.futures import Future
-from contextlib import asynccontextmanager, redirect_stderr, redirect_stdout
+from contextlib import (
+    asynccontextmanager,
+    contextmanager,
+    redirect_stderr,
+    redirect_stdout,
+)
 from datetime import datetime
 from functools import partial
 from pathlib import Path, PurePath
@@ -22,6 +27,7 @@
     Any,
     Awaitable,
     Callable,
+    Generator,
     Generic,
     Iterable,
     List,
@@ -411,6 +417,7 @@ def __init__(
         self._screenshot: str | None = None
         self._dom_lock = asyncio.Lock()
         self._dom_ready = False
+        self._batch_count = 0
         self.set_class(self.dark, "-dark-mode")
 
     @property
@@ -426,6 +433,30 @@ def children(self) -> Sequence["Widget"]:
         except ScreenError:
             return ()
 
+    @contextmanager
+    def batch_update(self) -> Generator[None, None, None]:
+        """Suspend all repaints until the end of the batch."""
+        self._begin_batch()
+        try:
+            yield
+        finally:
+            self._end_batch()
+
+    def _begin_batch(self) -> None:
+        """Begin a batch update."""
+        self._batch_count += 1
+
+    def _end_batch(self) -> None:
+        """End a batch update."""
+        self._batch_count -= 1
+        assert self._batch_count >= 0, "This won't happen if you use `batch_update`"
+        if not self._batch_count:
+            try:
+                self.screen.check_idle()
+            except ScreenStackError:
+                pass
+            self.check_idle()
+
     def animate(
         self,
         attribute: str,
@@ -1504,28 +1535,29 @@ async def invoke_ready_callback() -> None:
                     if inspect.isawaitable(ready_result):
                         await ready_result
 
-            try:
+            with self.batch_update():
                 try:
-                    await self._dispatch_message(events.Compose(sender=self))
-                    await self._dispatch_message(events.Mount(sender=self))
-                finally:
-                    self._mounted_event.set()
+                    try:
+                        await self._dispatch_message(events.Compose(sender=self))
+                        await self._dispatch_message(events.Mount(sender=self))
+                    finally:
+                        self._mounted_event.set()
 
-                Reactive._initialize_object(self)
+                    Reactive._initialize_object(self)
 
-                self.stylesheet.update(self)
-                self.refresh()
+                    self.stylesheet.update(self)
+                    self.refresh()
 
-                await self.animator.start()
+                    await self.animator.start()
 
-            except Exception:
-                await self.animator.stop()
-                raise
+                except Exception:
+                    await self.animator.stop()
+                    raise
 
-            finally:
-                self._running = True
-                await self._ready()
-                await invoke_ready_callback()
+                finally:
+                    self._running = True
+                    await self._ready()
+                    await invoke_ready_callback()
 
             try:
                 await self._process_messages_loop()
@@ -1611,11 +1643,12 @@ async def _on_compose(self) -> None:
             raise TypeError(
                 f"{self!r} compose() returned an invalid response; {error}"
             ) from error
+
         await self.mount_all(widgets)
 
     def _on_idle(self) -> None:
         """Perform actions when there are no messages in the queue."""
-        if self._require_stylesheet_update:
+        if self._require_stylesheet_update and not self._batch_count:
             nodes: set[DOMNode] = {
                 child
                 for node in self._require_stylesheet_update
@@ -1796,6 +1829,7 @@ async def _shutdown(self) -> None:
             self._writer_thread.stop()
 
     async def _on_exit_app(self) -> None:
+        self._begin_batch()  # Prevent repaint / layout while shutting down
         await self._message_queue.put(None)
 
     def refresh(self, *, repaint: bool = True, layout: bool = False) -> None:

src/textual/cli/previews/colors.py

@@ -72,7 +72,6 @@ def update_view(self) -> None:
         content.mount(ColorsView())
 
     def on_button_pressed(self, event: Button.Pressed) -> None:
-        self.bell()
         self.query(ColorGroup).remove_class("-active")
         group = self.query_one(f"#group-{event.button.id}", ColorGroup)
         group.add_class("-active")

src/textual/screen.py

@@ -359,7 +359,7 @@ async def _on_idle(self, event: events.Idle) -> None:
         # Check for any widgets marked as 'dirty' (needs a repaint)
         event.prevent_default()
 
-        if self.is_current:
+        if not self.app._batch_count and self.is_current:
             async with self.app._dom_lock:
                 if self.is_current:
                     if self._layout_required: