fix for simple app case

Makefile

@@ -6,3 +6,7 @@ format:
 	black src
 format-check:
 	black --check src
+docs-serve:
+	mkdocs serve
+docs-build:
+	mkdocs build

docs/examples/introduction/clock.py

@@ -16,7 +16,3 @@ class Clock(Widget):
 class ClockApp(App):
     def compose(self):
         yield Clock()
-
-
-app = ClockApp()
-app.run()

src/textual/app.py

@@ -7,6 +7,7 @@ import io
 import os
 import platform
 import sys
+import string
 import warnings
 from contextlib import redirect_stdout
 from pathlib import PurePath
@@ -108,6 +109,10 @@ class App(Generic[ReturnType], DOMNode):
     """The base class for Textual Applications"""
 
     CSS = """
+    $WIDGET {
+        background: $surface;
+        color: $text-surface;
+    }
     """
 
     CSS_PATH: str | None = None
@@ -721,8 +726,11 @@ class App(Generic[ReturnType], DOMNode):
             if self.css_path is not None:
                 self.stylesheet.read(self.css_path)
             if self.CSS is not None:
+                css_code = string.Template(self.CSS).safe_substitute(
+                    {"WIDGET": self.css_type}
+                )
                 self.stylesheet.add_source(
-                    self.CSS, path=f"<{self.__class__.__name__}>"
+                    css_code, path=f"<{self.__class__.__name__}>"
                 )
         except Exception as error:
             self.on_exception(error)
@@ -875,6 +883,8 @@ class App(Generic[ReturnType], DOMNode):
 
     def refresh(self, *, repaint: bool = True, layout: bool = False) -> None:
         self.screen.refresh(repaint=repaint, layout=layout)
+        self.check_idle()
+        # self.screen._refresh_layout()
 
     def _paint(self):
         """Perform a "paint" (draw the screen)."""
@@ -1062,10 +1072,12 @@ class App(Generic[ReturnType], DOMNode):
     async def handle_update(self, message: messages.Update) -> None:
         message.stop()
         self._paint()
+        print("UPDATE PAINT")
 
     async def handle_layout(self, message: messages.Layout) -> None:
         message.stop()
         self._paint()
+        print("LAYOUT PAINT")
 
     async def on_key(self, event: events.Key) -> None:
         if event.key == "tab":

src/textual/drivers/linux_driver.py

@@ -194,8 +194,6 @@ class LinuxDriver(Driver):
 
         fileno = self.fileno
 
-        print(1)
-
         def more_data() -> bool:
             """Check if there is more data to parse."""
             for key, events in selector.select(0.01):
@@ -203,28 +201,20 @@ class LinuxDriver(Driver):
                     return True
             return False
 
-        print(2)
         parser = XTermParser(self._target, more_data, self._debug)
         feed = parser.feed
 
         utf8_decoder = getincrementaldecoder("utf-8")().decode
         decode = utf8_decoder
         read = os.read
-        print(3)
         EVENT_READ = selectors.EVENT_READ
 
         try:
-            print(4)
             while not self.exit_event.is_set():
-                print(5)
                 selector_events = selector.select(0.1)
-                print(6)
                 for _selector_key, mask in selector_events:
-                    print(7)
                     if mask | EVENT_READ:
-                        print(8)
                         unicode_data = decode(read(fileno, 1024))
-                        print(9)
                         for event in feed(unicode_data):
                             self.process_event(event)
         except Exception as error:

src/textual/message_pump.py

@@ -268,6 +268,7 @@ class MessagePump:
                 self.app.on_exception(error)
                 break
             finally:
+                self._message_queue.task_done()
                 if self._message_queue.empty():
                     if not self._closed:
                         event = events.Idle(self)

src/textual/screen.py

@@ -30,9 +30,7 @@ class Screen(Widget):
     """A widget for the root of the app."""
 
     CSS = """
-    Screen {
-        background: $surface;
-        color: $text-surface;
+    $WIDGET {
         layout: vertical;
         overflow-y: auto;
     }
@@ -114,20 +112,19 @@ class Screen(Widget):
     def on_idle(self, event: events.Idle) -> None:
         # Check for any widgets marked as 'dirty' (needs a repaint)
         event.prevent_default()
-
         if self._layout_required:
             self._refresh_layout()
             self._layout_required = False
             self._dirty_widgets.clear()
-        elif self._dirty_widgets:
+        elif self._dirty_widgets or self._dirty_regions:
             self.update_timer.resume()
 
     def _on_update(self) -> None:
         """Called by the _update_timer."""
         # Render widgets together
-
-        if self._dirty_widgets:
+        if self._dirty_widgets or self._dirty_regions:
             self._compositor.update_widgets(self._dirty_widgets)
+            self._compositor.add_dirty_regions(self._dirty_regions)
             self.app._display(self._compositor.render())
             self._dirty_widgets.clear()
         self.update_timer.pause()

src/textual/widget.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 from fractions import Fraction
+import string
 from typing import (
     Any,
     Awaitable,
@@ -23,7 +24,6 @@ from . import errors
 from . import events
 from ._animator import BoundAnimator
 from ._border import Border
-from ._profile import timer
 from .box_model import BoxModel, get_box_model
 from ._context import active_app
 from ._types import Lines
@@ -35,7 +35,6 @@ from .message import Message
 from . import messages
 from ._layout import Layout
 from .reactive import Reactive, watch
-from .renderables.blank import Blank
 from .renderables.opacity import Opacity
 from .renderables.tint import Tint
 
@@ -178,9 +177,10 @@ class Widget(DOMNode):
         Args:
             app (App): App instance.
         """
+        css_code = string.Template(self.CSS).safe_substitute({"WIDGET": self.css_type})
         # Parser the Widget's CSS
         self.app.stylesheet.add_source(
-            self.CSS, f"{__file__}:<{self.__class__.__name__}>"
+            css_code, f"{__file__}:<{self.__class__.__name__}>"
         )
 
     def get_box_model(

src/textual/widgets/_button.py

@@ -17,7 +17,7 @@ class Button(Widget, can_focus=True):
 
     CSS = """
 
-    Button {
+    $WIDGET {
         width: auto;
         height: 3;
         background: $primary;
@@ -29,13 +29,13 @@ class Button(Widget, can_focus=True):
         text-style: bold;
     }
 
-    Button:hover {
+    $WIDGET:hover {
         background:$primary-darken-2;
         color: $text-primary-darken-2;
         border: tall $primary-lighten-1;
     }
 
-    App.-show-focus Button:focus {
+    App.-show-focus $WIDGET:focus {
         tint: $accent 20%;
     }