Fix scroll flicker (#2358)

* fix scroll flicker

* fix scroll flicker

* remove event

* do not delay scroll

* remove comment

* test fix

* remove commented code

* comment

* increase pause on click

* changelog [skip ci]

* wait on resume

* remove note [skip ci]

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 ### Changed
 
 - `textual run` execs apps in a new context.
+- Textual console no longer parses console markup.
 
 ### Added
 

src/textual/devtools/client.py

@@ -211,9 +211,9 @@ class DevtoolsClient:
             log: The log to write to devtools
         """
         if isinstance(log.objects_or_string, str):
-            self.console.print(log.objects_or_string)
+            self.console.print(log.objects_or_string, markup=False)
         else:
-            self.console.print(*log.objects_or_string)
+            self.console.print(*log.objects_or_string, markup=False)
 
         segments = self.console.export_segments()
 

src/textual/events.py

@@ -50,15 +50,6 @@ class Callback(Event, bubble=False, verbose=True):
         yield "callback", self.callback
 
 
-class InvokeCallbacks(Event, bubble=False, verbose=True):
-    """An internal event, sent to the screen to run callbacks.
-
-    - [ ] Bubbles
-    - [X] Verbose
-
-    """
-
-
 class ShutdownRequest(Event):
     pass
 

src/textual/message_pump.py

@@ -374,6 +374,7 @@ class MessagePump(metaclass=_MessagePumpMeta):
             **kwargs: Keyword arguments to pass to the callable.
         """
         self._next_callbacks.append(partial(callback, *args, **kwargs))
+        self.check_idle()
 
     def _on_invoke_later(self, message: messages.InvokeLater) -> None:
         # Forward InvokeLater message to the Screen
@@ -506,6 +507,7 @@ class MessagePump(metaclass=_MessagePumpMeta):
                             except Exception as error:
                                 self.app._handle_exception(error)
                                 break
+                    await self._flush_next_callbacks()
 
     async def _flush_next_callbacks(self) -> None:
         """Invoke pending callbacks in next callbacks queue."""

src/textual/pilot.py

@@ -100,11 +100,11 @@ class Pilot(Generic[ReturnType]):
             target_widget, offset, button=1, shift=shift, meta=meta, control=control
         )
         app.post_message(MouseDown(**message_arguments))
-        await self.pause()
+        await self.pause(0.1)
         app.post_message(MouseUp(**message_arguments))
-        await self.pause()
+        await self.pause(0.1)
         app.post_message(Click(**message_arguments))
-        await self.pause()
+        await self.pause(0.1)
 
     async def hover(
         self,

src/textual/screen.py

@@ -444,15 +444,12 @@ class Screen(Generic[ScreenResultType], Widget):
                 or self._dirty_widgets
             ):
                 self._update_timer.resume()
+                return
 
-        # The Screen is idle - a good opportunity to invoke the scheduled callbacks
+        await self._invoke_and_clear_callbacks()
-
-        if self._callbacks:
-            self._on_timer_update()
 
     def _on_timer_update(self) -> None:
         """Called by the _update_timer."""
-
         self._update_timer.pause()
         if self.is_current:
             if self._layout_required:
@@ -465,12 +462,11 @@ class Screen(Generic[ScreenResultType], Widget):
                 self._scroll_required = False
 
             if self._repaint_required:
-                self._update_timer.resume()
                 self._dirty_widgets.clear()
                 self._dirty_widgets.add(self)
                 self._repaint_required = False
 
-            if self._dirty_widgets and self.is_current:
+            if self._dirty_widgets:
                 self._compositor.update_widgets(self._dirty_widgets)
                 update = self._compositor.render_update(
                     screen_stack=self.app._background_screens
@@ -479,20 +475,12 @@ class Screen(Generic[ScreenResultType], Widget):
                 self._dirty_widgets.clear()
 
         if self._callbacks:
-            self.post_message(events.InvokeCallbacks())
+            self.call_next(self._invoke_and_clear_callbacks)
-
-    async def _on_invoke_callbacks(self, event: events.InvokeCallbacks) -> None:
-        """Handle PostScreenUpdate events, which are sent after the screen is updated"""
-        await self._invoke_and_clear_callbacks()
 
     async def _invoke_and_clear_callbacks(self) -> None:
         """If there are scheduled callbacks to run, call them and clear
         the callback queue."""
         if self._callbacks:
-            display_update = self._compositor.render_update(
-                screen_stack=self.app._background_screens
-            )
-            self.app._display(self, display_update)
             callbacks = self._callbacks[:]
             self._callbacks.clear()
             for callback in callbacks:

src/textual/scroll_view.py

@@ -7,6 +7,7 @@ from __future__ import annotations
 
 from rich.console import RenderableType
 
+from ._animator import EasingFunction
 from .containers import ScrollableContainer
 from .geometry import Size
 
@@ -111,3 +112,37 @@ class ScrollView(ScrollableContainer):
         from rich.panel import Panel
 
         return Panel(f"{self.scroll_offset} {self.show_vertical_scrollbar}")
+
+    # Custom scroll to which doesn't require call_after_refresh
+    def scroll_to(
+        self,
+        x: float | None = None,
+        y: float | None = None,
+        *,
+        animate: bool = True,
+        speed: float | None = None,
+        duration: float | None = None,
+        easing: EasingFunction | str | None = None,
+        force: bool = False,
+    ) -> None:
+        """Scroll to a given (absolute) coordinate, optionally animating.
+
+        Args:
+            x: X coordinate (column) to scroll to, or `None` for no change.
+            y: Y coordinate (row) to scroll to, or `None` for no change.
+            animate: Animate to new scroll position.
+            speed: Speed of scroll if `animate` is `True`; or `None` to use `duration`.
+            duration: Duration of animation, if `animate` is `True` and `speed` is `None`.
+            easing: An easing method for the scrolling animation.
+            force: Force scrolling even when prohibited by overflow styling.
+        """
+
+        self._scroll_to(
+            x,
+            y,
+            animate=animate,
+            speed=speed,
+            duration=duration,
+            easing=easing,
+            force=force,
+        )

src/textual/timer.py

@@ -131,20 +131,18 @@ class Timer:
                 continue
             now = _time.get_time()
             wait_time = max(0, next_timer - now)
-            if wait_time > 1 / 1000:
             await sleep(wait_time)
-
             count += 1
+            try:
+                await self._tick(next_timer=next_timer, count=count)
+            except EventTargetGone:
+                break
             await self._active.wait()
             if self._reset:
                 start = _time.get_time()
                 count = 0
                 self._reset = False
                 continue
-            try:
-                await self._tick(next_timer=next_timer, count=count)
-            except EventTargetGone:
-                break
 
     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"""

tests/test_call_later.py

@@ -39,4 +39,4 @@ async def test_call_after_refresh() -> None:
         app.call_after_refresh(callback)
         await asyncio.wait_for(called_event.wait(), 1)
         app_display_count = app.display_count
-        assert app_display_count > display_count
+        assert app_display_count == display_count