allow nested views

src/textual/_line_cache.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+
 import logging
 
 from typing import Iterable
@@ -8,21 +9,28 @@ from rich.console import Console, ConsoleOptions, RenderableType, RenderResult
 from rich.control import Control
 from rich.segment import Segment
 
+from ._loop import loop_last
 
 log = logging.getLogger("rich")
 
 
 class LineCache:
-    def __init__(self) -> None:
-        self.lines: list[list[Segment]] = []
-        self._dirty: list[bool] = []
-
-    def update(
-        self, console: Console, options: ConsoleOptions, renderable: RenderableType
-    ) -> None:
-        self.lines = console.render_lines(renderable, options, new_lines=True)
+    def __init__(self, lines: list[list[Segment]]) -> None:
+        self.lines = lines
         self._dirty = [True] * len(self.lines)
 
+    @classmethod
+    def from_renderable(
+        cls,
+        console: Console,
+        renderable: RenderableType,
+        width: int,
+        height: int,
+    ) -> "LineCache":
+        options = console.options.update_dimensions(width, height)
+        lines = console.render_lines(renderable, options)
+        return cls(lines)
+
     @property
     def dirty(self) -> bool:
         return any(self._dirty)
@@ -30,14 +38,22 @@ class LineCache:
     def __rich_console__(
         self, console: Console, options: ConsoleOptions
     ) -> RenderResult:
+
+        new_line = Segment.line()
         for line in self.lines:
             yield from line
+            yield new_line
 
-    def render(self, x: int, y: int) -> Iterable[Segment]:
+    def render(self, x: int, y: int, width: int, height: int) -> Iterable[Segment]:
         move_to = Control.move_to
-        for offset_y, (line, dirty) in enumerate(zip(self.lines, self._dirty), y):
+        lines = self.lines[:height]
+        new_line = Segment.line()
+        for last, (offset_y, (line, dirty)) in loop_last(
+            enumerate(zip(lines, self._dirty), y)
+        ):
             if dirty:
                 yield move_to(x, offset_y).segment
-                yield from line
-
+                yield from Segment.adjust_line_length(line, width)
+                if not last:
+                    yield new_line
         self._dirty[:] = [False] * len(self.lines)

src/textual/_xterm_parser.py

@@ -65,12 +65,12 @@ class XTermParser(Parser[events.Event]):
 
         while not self.is_eof:
             character = yield read1()
-            log.debug("character=%r", character)
+            # log.debug("character=%r", character)
             if character == ESC and ((yield self.peek_buffer()) or more_data()):
                 sequence: str = character
                 while True:
                     sequence += yield read1()
-                    log.debug(f"sequence=%r", sequence)
+                    # log.debug(f"sequence=%r", sequence)
                     keys = get_ansi_sequence(sequence, None)
                     if keys is not None:
                         for key in keys:

src/textual/app.py

@@ -9,10 +9,10 @@ import warnings
 
 from rich.control import Control
 from rich.layout import Layout
-from rich.repr import rich_repr, RichReprResult
+import rich.repr
 from rich.screen import Screen
 from rich import get_console
-from rich.console import Console
+from rich.console import Console, RenderableType
 
 from . import events
 from . import actions
@@ -21,6 +21,7 @@ from .driver import Driver
 from ._linux_driver import LinuxDriver
 from .message_pump import MessagePump
 from .view import View, LayoutView
+from .widget import Widget, WidgetBase
 
 log = logging.getLogger("rich")
 
@@ -28,9 +29,9 @@ log = logging.getLogger("rich")
 # asyncio will warn against resources not being cleared
 warnings.simplefilter("always", ResourceWarning)
 # https://github.com/boto/boto3/issues/454
-warnings.filterwarnings(
-    "ignore", category=ResourceWarning, message="unclosed.*<ssl.SSLSocket.*>"
-)
+# warnings.filterwarnings(
+#     "ignore", category=ResourceWarning, message="unclosed.*<ssl.SSLSocket.*>"
+# )
 
 
 LayoutDefinition = "dict[str, Any]"
@@ -47,7 +48,7 @@ class ShutdownError(Exception):
     pass
 
 
-@rich_repr
+@rich.repr.auto
 class App(MessagePump):
     view: View
 
@@ -68,24 +69,40 @@ class App(MessagePump):
         self.title = title
         self.view = view or self.create_default_view()
         self.children: set[MessagePump] = set()
+
+        self.focused: WidgetBase | None = None
+        self.mouse_over: WidgetBase | None = None
         self._driver: Driver | None = None
 
         self._action_targets = {"app": self, "view": self.view}
 
-    def __rich_repr__(self) -> RichReprResult:
+    def __rich_repr__(self) -> rich.repr.RichReprResult:
         yield "title", self.title
 
+    def __rich__(self) -> RenderableType:
+        return self.view
+
     @classmethod
     def run(
         cls, console: Console = None, screen: bool = True, driver: Type[Driver] = None
     ):
+        """Run the app.
+
+        Args:
+            console (Console, optional): Console object. Defaults to None.
+            screen (bool, optional): Enable application mode. Defaults to True.
+            driver (Type[Driver], optional): Driver class or None for default. Defaults to None.
+        """
+
         async def run_app() -> None:
             app = cls(console=console, screen=screen, driver_class=driver)
+
             await app.process_messages()
 
         asyncio.run(run_app())
 
     def create_default_view(self) -> View:
+        """Create the default view."""
         layout = Layout()
         layout.split_column(
             Layout(name="header", size=3, ratio=0),
@@ -105,6 +122,40 @@ class App(MessagePump):
         event = events.ShutdownRequest(sender=self)
         asyncio.run_coroutine_threadsafe(self.post_message(event), loop=loop)
 
+    async def set_focus(self, widget: Widget | None) -> None:
+        log.debug("set_focus %r", widget)
+        if widget == self.focused:
+            return
+
+        if widget is None:
+            if self.focused is not None:
+                focused = self.focused
+                self.focused = None
+                await focused.post_message(events.Blur(self))
+        elif widget.can_focus:
+            if self.focused is not None:
+                await self.focused.post_message(events.Blur(self))
+            if widget is not None and self.focused != widget:
+                self.focused = widget
+                await widget.post_message(events.Focus(self))
+
+    async def set_mouse_over(self, widget: WidgetBase | None) -> None:
+        if widget is None:
+            if self.mouse_over is not None:
+                try:
+                    await self.mouse_over.post_message(events.Leave(self))
+                finally:
+                    self.mouse_over = None
+        else:
+            if self.mouse_over != widget:
+                try:
+                    if self.mouse_over is not None:
+                        await self.mouse_over.forward_event(events.Leave(self))
+                    if widget is not None:
+                        await widget.forward_event(events.Enter(self))
+                finally:
+                    self.mouse_over = widget
+
     async def process_messages(self) -> None:
         try:
             await self._process_messages()
@@ -119,7 +170,7 @@ class App(MessagePump):
         driver = self._driver = self.driver_class(self.console, self)
 
         active_app.set(self)
-
+        self.view.set_parent(self)
         await self.add(self.view)
 
         await self.post_message(events.Startup(sender=self))
@@ -164,13 +215,12 @@ class App(MessagePump):
                 return
 
         if isinstance(event, events.InputEvent):
+            if isinstance(event, events.Key) and self.focused is not None:
+                await self.focused.forward_event(event)
             await self.view.forward_event(event)
         else:
             await super().on_event(event)
 
-    async def on_idle(self, event: events.Idle) -> None:
-        await self.view.post_message(event)
-
     async def action(self, action: str) -> None:
         """Perform an action.
 
@@ -235,7 +285,7 @@ if __name__ == "__main__":
 
     from .widgets.header import Header
     from .widgets.footer import Footer
-    from .widgets.window import Window
+
     from .widgets.placeholder import Placeholder
     from .scrollbar import ScrollBar
 
@@ -243,17 +293,6 @@ if __name__ == "__main__":
 
     import os
 
-    readme_path = os.path.join(
-        os.path.dirname(os.path.abspath(__file__)), "richreadme.md"
-    )
-    scroll_view = LayoutView()
-    scroll_bar = ScrollBar()
-    with open(readme_path, "rt") as fh:
-        readme = Markdown(fh.read(), hyperlinks=True, code_theme="fruity")
-    scroll_view.layout.split_row(
-        Layout(readme, ratio=1), Layout(scroll_bar, ratio=2, size=2)
-    )
-
     # from rich.console import Console
 
     # console = Console()
@@ -280,22 +319,31 @@ if __name__ == "__main__":
             footer.add_key("b", "Toggle sidebar")
             footer.add_key("q", "Quit")
 
-            readme_path = os.path.join(
-                os.path.dirname(os.path.abspath(__file__)), "richreadme.md"
-            )
-            scroll_view = LayoutView()
-            scroll_bar = ScrollBar()
-            with open(readme_path, "rt") as fh:
-                readme = Markdown(fh.read(), hyperlinks=True, code_theme="fruity")
-            scroll_view.layout.split_column(
-                Layout(readme, ratio=1), Layout(scroll_bar, ratio=2, size=2)
-            )
+            # readme_path = os.path.join(
+            #     os.path.dirname(os.path.abspath(__file__)), "richreadme.md"
+            # )
+            # scroll_view = LayoutView()
+            # scroll_bar = ScrollBar()
+            # with open(readme_path, "rt") as fh:
+            #     readme = Markdown(fh.read(), hyperlinks=True, code_theme="fruity")
+            # scroll_view.layout.split_column(
+            #     Layout(readme, ratio=1), Layout(scroll_bar, ratio=2, size=2)
+            # )
+            layout = Layout()
+            layout.split_column(Layout(name="l1"), Layout(name="l2"))
+            sub_view = LayoutView(name="Sub view", layout=layout)
+            await sub_view.mount_all(l1=Placeholder(), l2=Placeholder())
 
             await self.view.mount_all(
                 header=Header(self.title),
                 left=Placeholder(),
-                body=scroll_view,
+                body=sub_view,
                 footer=footer,
             )
 
+    # app = MyApp()
+    # from rich.console import Console
+
+    # console = Console()
+    # console.print(app, height=30)
     MyApp.run()

src/textual/events.py

@@ -226,18 +226,8 @@ class Timer(Event, type=EventType.TIMER):
         yield self.timer.name
 
 
-@rich_repr
 class Enter(Event, type=EventType.ENTER):
-    __slots__ = ["x", "y"]
-
-    def __init__(self, sender: MessageTarget, x: int, y: int) -> None:
-        super().__init__(sender)
-        self.x = x
-        self.y = y
-
-    def __rich_repr__(self) -> RichReprResult:
-        yield "x", self.x
-        yield "y", self.y
+    pass
 
 
 class Leave(Event, type=EventType.LEAVE):

src/textual/geometry.py

@@ -49,6 +49,10 @@ class Region(NamedTuple):
         x, y = point
         return ((self_x + width) > x >= self_x) and (((self_y + height) > y >= self_y))
 
+    def translate(self, x: int, y: int) -> Region:
+        _x, _y, width, height = self
+        return Region(self.x + _x, self.y + _y, width, height)
+
     def __contains__(self, other: Any) -> bool:
         try:
             x, y = other

src/textual/message.py

@@ -1,7 +1,7 @@
 from time import monotonic
 from typing import ClassVar
 
-from rich.repr import rich_repr
+import rich.repr
 
 from .case import camel_to_snake
 from ._types import MessageTarget
@@ -29,9 +29,8 @@ class Message:
         self._stop_propagaton = False
         super().__init__()
 
-    def __rich_repr__(self):
-        return
-        yield
+    def __rich_repr__(self) -> rich.repr.RichReprResult:
+        yield self.sender
 
     def __init_subclass__(cls, bubble: bool = False) -> None:
         super().__init_subclass__()

src/textual/message_pump.py

@@ -152,7 +152,7 @@ class MessagePump:
                 log.exception("error in dispatch_message")
                 raise
             finally:
-                if self._message_queue.empty():
+                if isinstance(message, events.Event) and self._message_queue.empty():
                     if not self._closed:
                         idle_handler = getattr(self, "on_idle", None)
                         if idle_handler is not None and not self._closed:
@@ -203,9 +203,11 @@ class MessagePump:
 
     async def emit(self, message: Message) -> bool:
         if self._parent:
+            log.debug("EMIT %r -> %r %r", self, self._parent, message)
             await self._parent.post_message_from_child(message)
             return True
         else:
+            log.warning("NO PARENT %r %r", self, message)
             return False
 
     async def on_timer(self, event: events.Timer) -> None:

src/textual/screen_update.py

@@ -0,0 +1,35 @@
+from __future__ import annotations
+
+from typing import Iterable
+
+from rich.console import Console, RenderableType
+from rich.control import Control
+from rich.segment import Segment, Segments
+
+from .geometry import Point
+from ._loop import loop_last
+
+
+class ScreenUpdate:
+    def __init__(
+        self, console: Console, renderable: RenderableType, width: int, height: int
+    ) -> None:
+
+        self.lines = console.render_lines(
+            renderable, console.options.update_dimensions(width, height)
+        )
+        self.offset = Point(0, 0)
+
+    def render(self, x: int, y: int) -> Iterable[Segment]:
+        move_to = Control.move_to
+        new_line = Segment.line()
+        for last, (offset_y, line) in loop_last(enumerate(self.lines, y)):
+            yield move_to(x, offset_y).segment
+            yield from line
+            if not last:
+                yield new_line
+
+    def __rich__(self) -> RenderableType:
+        x, y = self.offset
+        update = self.render(x, y)
+        return Segments(update)

src/textual/view.py

@@ -5,10 +5,10 @@ from time import time
 import logging
 from typing import Optional, Tuple, TYPE_CHECKING
 
-from rich.console import Console, ConsoleOptions, RenderResult
+from rich.console import Console, ConsoleOptions, RenderResult, RenderableType
 from rich.layout import Layout
 from rich.region import Region as LayoutRegion
-from rich.repr import rich_repr, RichReprResult
+import rich.repr
 from rich.segment import Segments
 
 from . import events
@@ -16,7 +16,7 @@ from ._context import active_app
 from .geometry import Dimensions, Region
 from .message import Message
 from .message_pump import MessagePump
-from .widget import Widget, UpdateMessage
+from .widget import Widget, WidgetBase, UpdateMessage
 from .widgets.header import Header
 
 if TYPE_CHECKING:
@@ -29,7 +29,7 @@ class NoWidget(Exception):
     pass
 
 
-class View(ABC, MessagePump):
+class View(ABC, WidgetBase):
     @property
     def app(self) -> "App":
         return active_app.get()
@@ -45,44 +45,46 @@ class View(ABC, MessagePump):
         yield
 
     @abstractmethod
-    async def mount(self, widget: MessagePump, *, slot: str = "main") -> None:
+    async def mount(self, widget: Widget, *, slot: str = "main") -> None:
         ...
 
-    @abstractmethod
-    def get_widget_at(self, x: int, y: int) -> Tuple[Widget, Region]:
-        ...
-
-    async def mount_all(self, **widgets: MessagePump) -> None:
+    async def mount_all(self, **widgets: Widget) -> None:
         for slot, widget in widgets.items():
             await self.mount(widget, slot=slot)
+        self.require_repaint()
 
     async def forward_event(self, event: events.Event) -> None:
         pass
 
 
-@rich_repr
+@rich.repr.auto
 class LayoutView(View):
-    layout: Layout
-
-    def __init__(
-        self,
-        layout: Layout = None,
-        name: str = "default",
-        title: str = "Layout Application",
-    ) -> None:
+    def __init__(self, layout: Layout = None, name: str = "default") -> None:
         self.name = name
-        self.title = title
         self.layout = layout or Layout()
-        self.mouse_over: MessagePump | None = None
-        self.focused: Widget | None = None
+        self.mouse_over: WidgetBase | None = None
+        self.focused: WidgetBase | None = None
         self.size = Dimensions(0, 0)
-        self._widgets: set[MessagePump] = set()
-        super().__init__()
+        self._widgets: set[WidgetBase] = set()
+        super().__init__(name)
         self.enable_messages(events.Idle)
 
-    def __rich_repr__(self) -> RichReprResult:
+    def __rich_repr__(self) -> rich.repr.RichReprResult:
         yield "name", self.name
 
+    @property
+    def is_root_view(self) -> bool:
+        return self._parent is self.app
+
+    # def check_repaint(self) -> bool:
+    #     return True
+
+    def render(self) -> RenderableType:
+        return self.layout
+
+    # def __rich__(self) -> Layout:
+    #     return self.render()
+
     # def __rich_console__(
     #     self, console: Console, options: ConsoleOptions
     # ) -> RenderResult:
@@ -90,77 +92,84 @@ class LayoutView(View):
     #     segments = console.render(self.layout, options.update_dimensions(width, height))
     #     yield from segments
 
-    def __rich__(self) -> Layout:
-        return self.layout
-
-    def get_widget_at(self, x: int, y: int) -> Tuple[Widget, Region]:
+    def get_widget_at(
+        self, x: int, y: int, offset_x: int = 0, offset_y: int = 0, deep: bool = False
+    ) -> Tuple[Widget, Region]:
         for layout, (layout_region, render) in self.layout.map.items():
             region = Region(*layout_region)
             if region.contains(x, y):
-                if isinstance(layout.renderable, Widget):
-                    return layout.renderable, region
-                else:
-                    break
-        raise NoWidget(f"No widget at ${x}, ${y}")
+                widget = layout.renderable
+                if deep and isinstance(layout.renderable, WidgetBase):
+                    widget = layout.renderable
+                    if isinstance(widget, View):
+                        translate_x = region.x
+                        translate_y = region.y
+                        widget, region = widget.get_widget_at(
+                            x - region.x, y - region.y, deep=True
+                        )
+                        region = region.translate(translate_x, translate_y)
+                return widget, region
 
-    async def repaint(self) -> None:
-        await self.emit(UpdateMessage(self))
-
-    async def on_event(self, event: events.Event) -> None:
-        if isinstance(event, events.Resize):
-            new_size = Dimensions(event.width, event.height)
-            if self.size != new_size:
-                self.size = new_size
-                await self.repaint()
-        await super().on_event(event)
+        raise NoWidget(f"No widget at {x}, {y}")
 
     async def on_message(self, message: Message) -> None:
-        log.debug("on_message %r", repr(message))
-        if isinstance(message, UpdateMessage):
-            widget = message.sender
-            if widget in self._widgets:
-                for layout, (region, render) in self.layout.map.items():
-                    if layout.renderable is widget:
-                        assert isinstance(widget, Widget)
-                        update = widget.render_update(region.x, region.y)
-                        segments = Segments(update)
-                        self.console.print(segments, end="")
 
-    async def mount(self, widget: MessagePump, *, slot: str = "main") -> None:
+        if isinstance(message, UpdateMessage):
+            widget = message.widget
+            # if widget in self._widgets:
+
+            for layout, (region, render) in self.layout.map.items():
+                if layout.renderable is message.sender:
+
+                    if not isinstance(widget, WidgetBase):
+                        continue
+
+                    log.debug("%r is_root %r", self, self.is_root_view)
+                    if self.is_root_view:
+                        log.debug("RENDERING %r %r %r", widget, message, region)
+                        try:
+                            update = widget.render_update(
+                                region.x + message.offset_x, region.y + message.offset_y
+                            )
+                        except Exception:
+                            log.exception("update error")
+                            raise
+                        self.console.print(Segments(update), end="")
+                    else:
+                        await self._parent.on_message(
+                            UpdateMessage(
+                                self,
+                                widget,
+                                offset_x=message.offset_x + region.x,
+                                offset_y=message.offset_y + region.y,
+                            )
+                        )
+                    break
+            else:
+                log.warning("Update widget not found")
+
+    # async def on_create(self, event: events.Created) -> None:
+    #     await self.mount(Header(self.title))
+
+    async def mount(self, widget: Widget, *, slot: str = "main") -> None:
         self.layout[slot].update(widget)
         await self.app.add(widget)
         widget.set_parent(self)
         await widget.post_message(events.Mount(sender=self))
         self._widgets.add(widget)
 
-    async def set_focus(self, widget: Optional[Widget]) -> None:
-        log.debug("set_focus %r", widget)
-        if widget == self.focused:
-            return
-
-        if widget is None:
-            if self.focused is not None:
-                focused = self.focused
-                self.focused = None
-                await focused.post_message(events.Blur(self))
-        elif widget.can_focus:
-            if self.focused is not None:
-                await self.focused.post_message(events.Blur(self))
-            if widget is not None and self.focused != widget:
-                self.focused = widget
-                await widget.post_message(events.Focus(self))
-
     async def layout_update(self) -> None:
         if not self.size:
             return
         width, height = self.size
         region_map = self.layout._make_region_map(width, height)
         for layout, region in region_map.items():
-            if isinstance(layout.renderable, Widget):
+            if isinstance(layout.renderable, WidgetBase):
                 await layout.renderable.post_message(
                     events.Resize(self, region.width, region.height)
                 )
-        await self.repaint()
+        self.app.refresh()
+        # await self.repaint()
 
     async def on_resize(self, event: events.Resize) -> None:
         self.size = Dimensions(event.width, event.height)
@@ -168,25 +177,15 @@ class LayoutView(View):
 
     async def _on_mouse_move(self, event: events.MouseMove) -> None:
         try:
-            widget, region = self.get_widget_at(event.x, event.y)
+            widget, region = self.get_widget_at(event.x, event.y, deep=True)
+            log.debug("mouse over %r %r", widget, region)
         except NoWidget:
-            if self.mouse_over is not None:
-                try:
-                    await self.mouse_over.post_message(events.Leave(self))
-                finally:
-                    self.mouse_over = None
+            await self.app.set_mouse_over(None)
         else:
-            if self.mouse_over != widget:
-                try:
-                    if self.mouse_over is not None:
-                        await self.mouse_over.post_message(events.Leave(self))
-                    if widget is not None:
-                        await widget.post_message(
-                            events.Enter(self, event.x - region.x, event.y - region.y)
-                        )
-                finally:
-                    self.mouse_over = widget
-            await widget.post_message(
+            await self.app.set_mouse_over(widget)
+
+            log.debug("posting mouse move to %r", widget)
+            await widget.forward_event(
                 events.MouseMove(
                     self,
                     event.x - region.x,
@@ -195,19 +194,21 @@ class LayoutView(View):
                     event.shift,
                     event.meta,
                     event.ctrl,
-                    screen_x=event.screen_x,
-                    screen_y=event.screen_y,
                 )
             )
 
     async def forward_event(self, event: events.Event) -> None:
-        if isinstance(event, (events.MouseDown)):
+        log.debug("FORWARD %r %r", self, event)
+        if isinstance(event, (events.Enter, events.Leave)):
+            await self.post_message(event)
+
+        elif isinstance(event, (events.MouseDown)):
             try:
-                widget, _region = self.get_widget_at(event.x, event.y)
+                widget, _region = self.get_widget_at(event.x, event.y, deep=True)
             except NoWidget:
-                await self.set_focus(None)
+                await self.app.set_focus(None)
             else:
-                await self.set_focus(widget)
+                await self.app.set_focus(widget)
 
         elif isinstance(event, events.MouseMove):
             await self._on_mouse_move(event)
@@ -219,6 +220,7 @@ class LayoutView(View):
                 pass
             else:
                 await widget.forward_event(event)
+
         elif isinstance(event, (events.MouseScrollDown, events.MouseScrollUp)):
             widget, _region = self.get_widget_at(event.x, event.y)
             scroll_widget = widget or self.focused
@@ -232,6 +234,3 @@ class LayoutView(View):
         visible = self.layout[layout_name].visible
         self.layout[layout_name].visible = not visible
         await self.layout_update()
-
-    async def on_idle(self, event: events.Idle) -> None:
-        await self.repaint()

src/textual/widget.py

@@ -13,14 +13,15 @@ from typing import (
 
 from rich.align import Align
 
-from rich.console import Console, ConsoleOptions, RenderableType, RenderResult
+from rich.console import Console, ConsoleOptions, RenderableType
 from rich.pretty import Pretty
 from rich.panel import Panel
-from rich.repr import rich_repr, RichReprResult
+import rich.repr
 from rich.segment import Segment
 
 from . import events
 from ._context import active_app
+from ._loop import loop_last
 from ._line_cache import LineCache
 from .message import Message
 from .message_pump import MessagePump
@@ -33,17 +34,39 @@ if TYPE_CHECKING:
 
 log = getLogger("rich")
 
-T = TypeVar("T")
-
 
+@rich.repr.auto
 class UpdateMessage(Message):
+    def __init__(
+        self,
+        sender: MessagePump,
+        widget: Widget,
+        offset_x: int = 0,
+        offset_y: int = 0,
+    ):
+        super().__init__(sender)
+        self.widget = widget
+        self.offset_x = offset_x
+        self.offset_y = offset_y
+
+    def __rich_repr__(self) -> rich.repr.RichReprResult:
+        yield self.sender
+        yield "widget"
+        yield "offset_x", self.offset_x, 0
+        yield "offset_y", self.offset_y, 0
+
     def can_batch(self, message: Message) -> bool:
         return isinstance(message, UpdateMessage) and message.sender == self.sender
 
 
-class Reactive(Generic[T]):
+ReactiveType = TypeVar("ReactiveType")
+
+
+class Reactive(Generic[ReactiveType]):
     def __init__(
-        self, default: T, validator: Callable[[object, T], T] | None = None
+        self,
+        default: ReactiveType,
+        validator: Callable[[object, ReactiveType], ReactiveType] | None = None,
     ) -> None:
         self._default = default
         self.validator = validator
@@ -52,10 +75,10 @@ class Reactive(Generic[T]):
         self.internal_name = f"_{name}"
         setattr(owner, self.internal_name, self._default)
 
-    def __get__(self, obj: "Widget", obj_type: type[object]) -> T:
+    def __get__(self, obj: "Widget", obj_type: type[object]) -> ReactiveType:
         return getattr(obj, self.internal_name)
 
-    def __set__(self, obj: "Widget", value: T) -> None:
+    def __set__(self, obj: "Widget", value: ReactiveType) -> None:
         if getattr(obj, self.internal_name) != value:
             log.debug("%s -> %s", self.internal_name, value)
             if self.validator:
@@ -64,7 +87,8 @@ class Reactive(Generic[T]):
             obj.require_repaint()
 
 
-class Widget(MessagePump):
+@rich.repr.auto
+class WidgetBase(MessagePump):
     _count: ClassVar[int] = 0
     can_focus: bool = False
 
@@ -74,10 +98,9 @@ class Widget(MessagePump):
         self.size = Dimensions(0, 0)
         self.size_changed = False
         self._repaint_required = False
-        self._line_cache: LineCache = LineCache()
 
         super().__init__()
-        self.disable_messages(events.MouseMove)
+        # self.disable_messages(events.MouseMove)
 
     def __init_subclass__(
         cls,
@@ -86,9 +109,12 @@ class Widget(MessagePump):
         super().__init_subclass__()
         cls.can_focus = can_focus
 
-    def __rich_repr__(self) -> RichReprResult:
+    def __rich_repr__(self) -> rich.repr.RichReprResult:
         yield "name", self.name
 
+    def __rich__(self) -> RenderableType:
+        return self.render()
+
     @property
     def app(self) -> "App":
         """Get the current app."""
@@ -97,39 +123,60 @@ class Widget(MessagePump):
     @property
     def console(self) -> Console:
         """Get the current console."""
-        try:
-            return active_app.get().console
-        except LookupError:
-            return Console()
-
-    # def __rich__(self) -> LineCache:
-    #     return self.line_cache
-
-    def __rich_console__(
-        self, console: Console, options: ConsoleOptions
-    ) -> RenderResult:
-        renderable = self.render(console, options)
-        self._line_cache.update(console, options, renderable)
-        yield self._line_cache
+        return active_app.get().console
 
     def require_repaint(self) -> None:
+        """Mark widget as requiring a repaint.
+
+        Actual repaint is done by parent on idle.
+        """
         self._repaint_required = True
 
+    def check_repaint(self) -> bool:
+        return True
+        return self._repaint_required
+
     async def forward_event(self, event: events.Event) -> None:
         await self.post_message(event)
 
     async def refresh(self) -> None:
-        self._repaint_required = True
+        """Re-render the window and repaint it."""
+        self.require_repaint()
         await self.repaint()
 
     async def repaint(self) -> None:
-        await self.emit(UpdateMessage(self))
+        """Instructs parent to repaint this widget."""
+        await self.emit(UpdateMessage(self, self))
 
     def render_update(self, x: int, y: int) -> Iterable[Segment]:
-        width, height = self.size
-        yield from self.line_cache.render(x, y, width, height)
+        """Render an update to a portion of the screen.
 
-    def render(self, console: Console, options: ConsoleOptions) -> RenderableType:
+        Args:
+            x (int): X offset from origin.
+            y (int): Y offset form origin.
+
+        Returns:
+            Iterable[Segment]: Partial update.
+        """
+        return
+
+        width, height = self.size
+        lines = self.console.render_lines(
+            self.render(), self.console.options.update_dimensions(width, height)
+        )
+
+        new_line = Segment.line()
+        for last, line in loop_last(lines):
+            yield from line
+            if not last:
+                yield new_line
+
+    def render(self) -> RenderableType:
+        """Get renderable for widget.
+
+        Returns:
+            RenderableType: Any renderable
+        """
         return Panel(
             Align.center(Pretty(self), vertical="middle"), title=self.__class__.__name__
         )
@@ -149,5 +196,56 @@ class Widget(MessagePump):
         await super().on_event(event)
 
     async def on_idle(self, event: events.Idle) -> None:
-        if self.line_cache is None or self.line_cache.dirty:
+        if self.check_repaint():
+            log.debug("REPAINTING")
             await self.repaint()
+
+
+class Widget(WidgetBase):
+    def __init__(self, name: str | None = None) -> None:
+        super().__init__(name)
+        self._line_cache: LineCache | None = None
+
+    @property
+    def line_cache(self) -> LineCache:
+
+        if self._line_cache is None:
+            width, height = self.size
+            start = time()
+            try:
+                renderable = self.render()
+            except Exception:
+                log.exception("error in render")
+                raise
+            self._line_cache = LineCache.from_renderable(
+                self.console, renderable, width, height
+            )
+            log.debug("%.1fms %r render elapsed", (time() - start) * 1000, self)
+        assert self._line_cache is not None
+        return self._line_cache
+
+    # def __rich__(self) -> LineCache:
+    #     return self.line_cache
+
+    def render(self) -> RenderableType:
+        return self.line_cache
+
+    def require_repaint(self) -> None:
+        self._line_cache = None
+        super().require_repaint()
+
+    def check_repaint(self) -> bool:
+        return self._line_cache is None or self.line_cache.dirty
+
+    def render_update(self, x: int, y: int) -> Iterable[Segment]:
+        """Render an update to a portion of the screen.
+
+        Args:
+            x (int): X offset from origin.
+            y (int): Y offset form origin.
+
+        Returns:
+            Iterable[Segment]: Partial update.
+        """
+        width, height = self.size
+        yield from self.line_cache.render(x, y, width, height)

src/textual/widgets/footer.py

@@ -17,7 +17,7 @@ class Footer(Widget):
     def add_key(self, key: str, label: str) -> None:
         self.keys.append((key, label))
 
-    def render(self, console: Console, options: ConsoleOptions) -> RenderableType:
+    def render(self) -> RenderableType:
 
         text = Text(
             style="white on dark_green",

src/textual/widgets/header.py

@@ -32,7 +32,7 @@ class Header(Widget):
     def get_clock(self) -> str:
         return datetime.now().time().strftime("%X")
 
-    def render(self, console: Console, options: ConsoleOptions) -> RenderableType:
+    def render(self) -> RenderableType:
 
         header_table = Table.grid(padding=(0, 1), expand=True)
         header_table.style = self.style

src/textual/widgets/placeholder.py

@@ -3,23 +3,24 @@ from rich.align import Align
 from rich.console import Console, ConsoleOptions, RenderableType
 from rich.panel import Panel
 from rich.pretty import Pretty
-from rich.repr import RichReprResult
+import rich.repr
 
 from .. import events
 from ..widget import Reactive, Widget
 
 
+@rich.repr.auto
 class Placeholder(Widget, can_focus=True):
 
     has_focus: Reactive[bool] = Reactive(False)
     mouse_over: Reactive[bool] = Reactive(False)
 
-    def __rich_repr__(self) -> RichReprResult:
+    def __rich_repr__(self) -> rich.repr.RichReprResult:
         yield "name", self.name
         yield "has_focus", self.has_focus
         yield "mouse_over", self.mouse_over
 
-    def render(self, console: Console, options: ConsoleOptions) -> RenderableType:
+    def render(self) -> RenderableType:
         return Panel(
             Align.center(Pretty(self), vertical="middle"),
             title=self.__class__.__name__,

src/textual/widgets/window.py

@@ -67,7 +67,7 @@ class Window(Widget):
         self.renderable = renderable
         del self._lines[:]
 
-    def render(self, console: Console, options: ConsoleOptions) -> RenderableType:
+    def render(self) -> RenderableType:
         height = self.size.height
         lines = self.get_lines(console, options)
         position = int(self.position)