fix screenshots

docs/examples/introduction/timers.css

@@ -1,12 +1,12 @@
 TimerWidget {
     layout: horizontal;
-    height: 5;
     background: $panel-darken-1;
     border: tall $panel-darken-2;
+    height: 5;
+    min-width: 50;
     margin: 1;
     padding: 0 1;
     transition: background 300ms linear;
-    min-width: 50;
 }
 
 TimerWidget.started {   
@@ -35,6 +35,14 @@ Button {
     dock: left;
 }
 
+#stop {
+    dock: left;
+    display: none;
+}
+
+#reset {
+    dock: right;
+}
 
 TimerWidget.started #start {
     display: none
@@ -48,11 +56,3 @@ TimerWidget.started #reset {
     visibility: hidden
 }
 
-#stop {
-    dock: left;
-    display: none;
-}
-
-#reset {
-    dock: right;
-}

docs/examples/introduction/timers.py

@@ -91,6 +91,6 @@ class TimerApp(App):
             timers.last().remove()
 
 
-app = TimerApp(title="TimerApp", css_path="timers.css")
+app = TimerApp(css_path="timers.css")
 if __name__ == "__main__":
     app.run()

docs/introduction.md

@@ -10,6 +10,11 @@ By the end of this page you should have a good idea of the steps involved in cre
 - Installed `textual` from Pypi.
 - Basic Python skills.
 
+
+```{.textual path="docs/examples/introduction/timers.py"}
+
+``` 
+
 ## A Simple App
 
 Let's looks at the simplest possible Textual app.

src/textual/_doc.py

@@ -12,6 +12,7 @@ def format_svg(source, language, css_class, options, md, attrs, **kwargs):
     os.environ["LINES"] = attrs.get("lines", "24")
     path = attrs.get("path")
 
+    print(f"screenshotting {path!r}")
     if path:
         cwd = os.getcwd()
         examples_path, filename = os.path.split(path)
@@ -34,4 +35,5 @@ def format_svg(source, language, css_class, options, md, attrs, **kwargs):
         app = app_vars["app"]
         app.run()
         svg = app._screenshot
+
     return svg

src/textual/_segment_tools.py

@@ -188,6 +188,6 @@ def align_lines(
         get_line_length = Segment.get_line_length
         for line in lines:
             left_space = width - get_line_length(line)
-            yield [*line, Segment(" " * left_space, style)]
+            yield [Segment(" " * left_space, style), *line]
 
     yield from blank_lines(bottom_blank_lines)

src/textual/_timer.py

@@ -61,6 +61,7 @@ class Timer:
         self._repeat = repeat
         self._skip = skip
         self._active = Event()
+        self._task: Task | None = None
         if not pause:
             self._active.set()
 
@@ -82,17 +83,21 @@ class Timer:
         Returns:
             Task: A Task instance for the timer.
         """
-        self._task = asyncio.create_task(self._run())
+        self._task = asyncio.create_task(self.run())
         return self._task
 
     def stop_no_wait(self) -> None:
         """Stop the timer."""
-        self._task.cancel()
+        if self._task is not None:
+            self._task.cancel()
+            self._task = None
 
     async def stop(self) -> None:
         """Stop the timer, and block until it exits."""
-        self._task.cancel()
+        if self._task is not None:
-        await self._task
+            self._active.set()
+            self._task.cancel()
+            self._task = None
 
     def pause(self) -> None:
         """Pause the timer."""
@@ -102,31 +107,35 @@ class Timer:
         """Result a paused timer."""
         self._active.set()
 
+    async def run(self) -> None:
+        """Run the timer task."""
+        try:
+            await self._run()
+        except CancelledError:
+            pass
+
     async def _run(self) -> None:
         """Run the timer."""
         count = 0
         _repeat = self._repeat
         _interval = self._interval
         start = _clock.get_time_no_wait()
-        try:
+        while _repeat is None or count <= _repeat:
-            while _repeat is None or count <= _repeat:
+            next_timer = start + ((count + 1) * _interval)
-                next_timer = start + ((count + 1) * _interval)
+            now = await _clock.get_time()
-                now = await _clock.get_time()
+            if self._skip and next_timer < now:
-                if self._skip and next_timer < now:
-                    count += 1
-                    continue
-                now = await _clock.get_time()
-                wait_time = max(0, next_timer - now)
-                if wait_time:
-                    await _clock.sleep(wait_time)
                 count += 1
-                try:
+                continue
-                    await self._tick(next_timer=next_timer, count=count)
+            now = await _clock.get_time()
-                except EventTargetGone:
+            wait_time = max(0, next_timer - now)
-                    break
+            if wait_time:
-                await self._active.wait()
+                await _clock.sleep(wait_time)
-        except CancelledError:
+            count += 1
-            pass
+            try:
+                await self._tick(next_timer=next_timer, count=count)
+            except EventTargetGone:
+                break
+            await self._active.wait()
 
     async def _tick(self, *, next_timer: float, count: int) -> None:
         """Triggers the Timer's action: either call its callback, or sends an event to its target"""
@@ -140,5 +149,4 @@ class Timer:
                 count=count,
                 callback=self._callback,
             )
-
             await self.target.post_priority_message(event)

src/textual/app.py

@@ -144,7 +144,7 @@ class App(Generic[ReturnType], DOMNode):
         log_color_system: Literal[
             "auto", "standard", "256", "truecolor", "windows"
         ] = "auto",
-        title: str = "Textual Application",
+        title: str | None = None,
         css_path: str | PurePath | None = None,
         watch_css: bool = False,
     ):
@@ -189,7 +189,10 @@ class App(Generic[ReturnType], DOMNode):
         self.animate = self._animator.bind(self)
         self.mouse_position = Offset(0, 0)
         self.bindings = Bindings()
-        self._title = title
+        if title is None:
+            self._title = f"{self.__class__.__name__}"
+        else:
+            self._title = title
 
         self._log_console: Console | None = None
         self._log_file: TextIO | None = None
@@ -1015,7 +1018,7 @@ class App(Generic[ReturnType], DOMNode):
             self._screenshot = svg  # type: ignore
             await self.shutdown()
 
-        self.set_timer(screenshot_timer, on_screenshot)
+        self.set_timer(screenshot_timer, on_screenshot, name="screenshot timer")
 
     def on_mount(self) -> None:
         widgets = self.compose()

src/textual/dom.py

@@ -105,7 +105,7 @@ class DOMNode(MessagePump):
             self._auto_refresh_timer = None
         if interval is not None:
             self._auto_refresh_timer = self.set_interval(
-                interval, self._automatic_refresh
+                interval, self._automatic_refresh, name=f"auto refresh {self!r}"
             )
         self._auto_refresh = interval
 

src/textual/drivers/headless_driver.py

@@ -1,14 +1,44 @@
 from __future__ import annotations
 
-
+import asyncio
 from ..driver import Driver
+from ..geometry import Size
+from .. import events
 
 
 class HeadlessDriver(Driver):
     """A do-nothing driver for testing."""
 
+    def _get_terminal_size(self) -> tuple[int, int]:
+        width: int | None = 80
+        height: int | None = 25
+        import shutil
+
+        try:
+            width, height = shutil.get_terminal_size()
+        except (AttributeError, ValueError, OSError):
+            try:
+                width, height = shutil.get_terminal_size()
+            except (AttributeError, ValueError, OSError):
+                pass
+        width = width or 80
+        height = height or 25
+        return width, height
+
     def start_application_mode(self) -> None:
-        pass
+        loop = asyncio.get_running_loop()
+
+        def send_size_event():
+            terminal_size = self._get_terminal_size()
+            width, height = terminal_size
+            textual_size = Size(width, height)
+            event = events.Resize(self._target, textual_size, textual_size)
+            asyncio.run_coroutine_threadsafe(
+                self._target.post_message(event),
+                loop=loop,
+            )
+
+        send_size_event()
 
     def disable_input(self) -> None:
         pass

src/textual/message_pump.py

@@ -254,7 +254,8 @@ class MessagePump(metaclass=MessagePumpMeta):
         if self._closed or self._closing:
             return
         self._closing = True
-        for timer in self._timers:
+        stop_timers = list(self._timers)
+        for timer in stop_timers:
             await timer.stop()
         self._timers.clear()
         await self._message_queue.put(MessagePriority(None))
@@ -274,7 +275,7 @@ class MessagePump(metaclass=MessagePumpMeta):
             pass
         finally:
             self._running = False
-            for timer in self._timers:
+            for timer in list(self._timers):
                 await timer.stop()
 
     async def _process_messages(self) -> None:

src/textual/screen.py

@@ -33,8 +33,6 @@ class Screen(Widget):
 
     CSS = """
     Screen {
-        color: $text-background;
-        background: $background;
         layout: vertical;
         overflow-y: auto;
     }

src/textual/widgets/_header.py

@@ -41,7 +41,7 @@ class HeaderClock(Widget):
     """
 
     def on_mount(self) -> None:
-        self.set_interval(1, callback=self.refresh)
+        self.set_interval(1, callback=self.refresh, name=f"update header clock")
 
     def render(self):
         return Text(datetime.now().time().strftime("%X"))