dictionary example

docs/examples/events/dictionary.css

@@ -0,0 +1,29 @@
+Screen {
+    background: $panel;
+}
+
+TextInput {
+    dock: top;
+    border: tall $background;
+    width: 100%;
+    height: 1;
+    padding: 0 1;
+    margin: 1 1 0 1;
+    background: $boost;
+}
+
+TextInput:focus {
+    border: tall $accent;
+}
+
+#results {
+    width: auto;   
+    min-height: 100%;
+}
+
+#results-container {
+    background: $background 50%;
+    overflow: auto;    
+    margin: 1 2;    
+    height: 100%;
+}

docs/examples/events/dictionary.py

@@ -0,0 +1,43 @@
+import asyncio
+
+try:
+    import httpx
+except ImportError:
+    raise ImportError("Please install http with 'pip install httpx' ")
+
+from rich.json import JSON
+
+from textual.app import App, ComposeResult
+from textual.layout import Vertical
+from textual.widgets import Static, TextInput
+
+
+class DictionaryApp(App):
+    """Searches ab dictionary API as-you-type."""
+
+    def compose(self) -> ComposeResult:
+        yield TextInput(placeholder="Search for a word")
+        yield Vertical(Static(id="results", fluid=False), id="results-container")
+
+    async def on_text_input_changed(self, message: TextInput.Changed) -> None:
+        """A coroutine to handle a text changed message."""
+        if message.value:
+            # Look up the word in the background
+            asyncio.create_task(self.lookup_word(message.value))
+        else:
+            # Clear the results
+            self.query_one("#results", Static).update()
+
+    async def lookup_word(self, word: str) -> None:
+        """Looks up a word."""
+        url = f"https://api.dictionaryapi.dev/api/v2/entries/en/{word}"
+        async with httpx.AsyncClient() as client:
+            results = (await client.get(url)).text
+
+        if word == self.query_one(TextInput).value:
+            self.query_one("#results", Static).update(JSON(results))
+
+
+app = DictionaryApp(css_path="dictionary.css")
+if __name__ == "__main__":
+    app.run()

docs/guide/events.md

@@ -110,9 +110,24 @@ The message class is defined within the widget class itself. This is not strictl
 - If reduces the amount of imports. If you were to import ColorButton, you have access to the message class via `ColorButton.Selected`.
 - It creates a namespace for the handler. So rather than `on_selected`, the handler name becomes `on_color_button_selected`. This makes it less likely that your chosen name will clash with another message.
 
+
+## Sending events
+
+In the previous example we used [emit()][textual.message_pump.MessagePump.emit] to send an event to it's parent. We could also have used [emit_no_wait()][textual.message_pump.MessagePump.emit_no_wait] for non async code. Sending messages in this way allows you to write custom widgets without needing to know in what context they will be used.
+
+There are other ways of sending (posting) messages, which you may need to use less frequently.
+
+- [post_message][textual.message_pump.MessagePump.post_message] To post a message to a particular event.
+- [post_message_no_wait][textual.message_pump.MessagePump.post_message_no_wait] The non-async version of `post_message`.
+
+
+## Message handlers
+
+Most of the logic in a Textual app will be written in message handlers. Let's explore handlers in more detail.
+
 ### Handler naming
 
-Let's recap on the scheme that Textual uses to map messages classes on to a Python method name.
+Textual uses the following scheme to map messages classes on to a Python method.
 
 - Start with `"on_"`.
 - Add the messages namespace (if any) converted from CamelCase to snake_case plus an underscore `"_"`
@@ -122,12 +137,56 @@ Let's recap on the scheme that Textual uses to map messages classes on to a Pyth
 --8<-- "docs/images/events/naming.excalidraw.svg"
 </div>
 
-### Sending events
+### Handler arguments
 
-In the previous example we used [emit()][textual.message_pump.MessagePump.emit] to send an event to it's parent. We could also have used [emit_no_wait()][textual.message_pump.MessagePump.emit_no_wait] for non async code. Sending messages in this way allows you to write custom widgets without needing to know in what context they will be used.
+Message handler methods can be written with or without a positional argument. If you add a positional argument, Textual will call the handler with the event object. The following handler (taken from custom01.py above) contains a `message` parameter. The body of the code makes use of the message to set a preset color.
 
-There are other ways of sending (posting) messages, which you may need to use less frequently.
+```python
+    def on_color_button_selected(self, message: ColorButton.Selected) -> None:
+        self.screen.styles.animate("background", message.color, duration=0.5)
+```
 
-- [post_message][textual.message_pump.MessagePump.post_message] To post a message to a particular event.
-- [post_message_no_wait][textual.message_pump.MessagePump.post_message_no_wait] The non-async version of `post_message`.
+If the body of your handler doesn't require any information in the message you can omit it from the method signature. If we just want to play a bell noise when the button is clicked, we could write our handler like this:
 
+```python
+    def on_color_button_selected(self) -> None:
+        self.app.bell()
+```
+
+This pattern is a convenience that saves writing out a parameter that may not be used.
+
+### Async handlers
+
+Method handlers may be coroutines. If you prefix your handlers with the `async` keyword, Textual will `await` them. This lets your handler use the `await` keyword for asynchronous APIs.
+
+If your event handlers are coroutines it will allow multiple events to be processed concurrently, but bear in mind an individual widget (or app) will not be able to pick up a new message from the message queue until the handler has returned. This is rarely a problem in practice; as long has handlers return within a few milliseconds the UI will remain responsive. But slow handlers might make your app hard to use.
+
+!!! info
+
+    To re-use the chef analogy, if an order comes in for beef wellington (which takes a while to cook), orders may start to pile up and customers may have to wait for their meal. The _solution_ would be to have another chef work on the wellington while the first chef picks up new orders.
+
+Network access is a common cause of slow handlers. If you try to retrieve a file from the internet, the message handler may take anything up to a few seconds to return, which would prevent the widget or app from updating during that time. The solution is to launch a new asyncio task to do the network task in the background.
+
+Let's look at an example which looks up word definitions from an [api](https://dictionaryapi.dev/) as you type.
+
+!!! note
+
+    You will need to install [httpx](https://www.python-httpx.org/) with `pip install httpx` to run this example.
+
+=== "dictionary.py"
+
+    ```python title="dictionary.py" hl_lines="26"
+    --8<-- "docs/examples/events/dictionary.py"
+    ```
+=== "dictionary.css"
+
+    ```python title="dictionary.css" 
+    --8<-- "docs/examples/events/dictionary.css"
+    ```
+
+=== "Output"
+
+    ```{.textual path="docs/examples/events/dictionary.py" press="tab,t,e,x,t,_,_,_,_,_,_,_,_,_,_,_"}
+    ```
+
+Note the highlighted line in the above code which calls `asyncio.create_task` to run coroutine in the background. Without this you would find typing in to the text box to be unresponsive.

sandbox/darren/file_search.py

@@ -58,7 +58,7 @@ class FileSearchApp(App):
         self.mount(file_table_wrapper=Widget(self.file_table))
         self.mount(search_bar=self.search_bar)
 
-    def on_text_widget_base_changed(self, event: TextWidgetBase.Changed) -> None:
+    def on_text_input_changed(self, event: TextInput.Changed) -> None:
         self.file_table.filter = event.value
 
 

sandbox/input.py

@@ -48,7 +48,7 @@ class InputApp(App[str]):
         )
         self.mount(text_area=TextArea())
 
-    def on_text_widget_base_changed(self, event: TextWidgetBase.Changed) -> None:
+    def on_text_input_changed_changed(self, event: TextInput.Changed) -> None:
         try:
             value = float(event.value)
         except ValueError:

src/textual/app.py

@@ -1305,21 +1305,6 @@ class App(Generic[ReturnType], DOMNode):
                 self._end_update()
             console.file.flush()
 
-    def measure(self, renderable: RenderableType, max_width=100_000) -> int:
-        """Get the optimal width for a widget or renderable.
-
-        Args:
-            renderable (RenderableType): A renderable (including Widget)
-            max_width ([type], optional): Maximum width. Defaults to 100_000.
-
-        Returns:
-            int: Number of cells required to render.
-        """
-        measurement = Measurement.get(
-            self.console, self.console.options.update(max_width=max_width), renderable
-        )
-        return measurement.maximum
-
     def get_widget_at(self, x: int, y: int) -> tuple[Widget, Region]:
         """Get the widget under the given coordinates.
 

src/textual/cli/previews/easing.py

@@ -111,7 +111,7 @@ class EasingApp(App):
         self.animated_bar.position = value
         self.opacity_widget.styles.opacity = 1 - value / END_POSITION
 
-    def on_text_widget_base_changed(self, event: TextWidgetBase.Changed):
+    def on_text_input_changed(self, event: TextInput.Changed):
         if event.sender.id == "duration-input":
             new_duration = _try_float(event.value)
             if new_duration is not None:

src/textual/design.py

@@ -174,8 +174,6 @@ class ColorSystem:
         for name, color in COLORS:
             is_dark_shade = dark and name in DARK_SHADES
             spread = luminosity_spread
-            if name == "panel":
-                spread /= 2
             for shade_name, luminosity_delta in luminosity_range(spread):
                 if is_dark_shade:
                     dark_background = background.blend(color, 0.15)
@@ -188,8 +186,8 @@ class ColorSystem:
                     colors[f"{name}{shade_name}"] = shade_color.hex
 
         colors["text"] = "auto 95%"
-        colors["text-muted"] = "auto 80%"
-        colors["text-disabled"] = "auto 60%"
+        colors["text-muted"] = "auto 50%"
+        colors["text-disabled"] = "auto 30%"
 
         return colors
 

src/textual/render.py

@@ -1,4 +1,5 @@
 from rich.console import Console, RenderableType
+from rich.protocol import rich_cast
 
 
 def measure(console: Console, renderable: RenderableType, default: int) -> int:
@@ -12,6 +13,7 @@ def measure(console: Console, renderable: RenderableType, default: int) -> int:
     Returns:
         int: Width in cells
     """
+    renderable = rich_cast(renderable)
     get_console_width = getattr(renderable, "__rich_measure__", None)
     if get_console_width is not None:
         render_width = get_console_width(console, console.options).normalize().maximum

src/textual/widget.py

@@ -7,8 +7,13 @@ from operator import attrgetter
 from typing import TYPE_CHECKING, ClassVar, Collection, Iterable, NamedTuple, cast
 
 import rich.repr
-from rich.console import Console, ConsoleRenderable, JustifyMethod, RenderableType
-from rich.measure import Measurement
+from rich.console import (
+    Console,
+    ConsoleRenderable,
+    RichCast,
+    JustifyMethod,
+    RenderableType,
+)
 from rich.segment import Segment
 from rich.style import Style
 from rich.styled import Styled
@@ -74,7 +79,7 @@ class Widget(DOMNode):
         scrollbar-background-hover: $panel-darken-2;
         scrollbar-color: $primary-lighten-1;
         scrollbar-color-active: $warning-darken-1;
-        scrollbar-corner-color: $panel-darken-3;
+        scrollbar-corner-color: $panel-darken-1;
         scrollbar-size-vertical: 2;
         scrollbar-size-horizontal: 1;
     }
@@ -321,8 +326,6 @@ class Widget(DOMNode):
             self.get_content_width,
             self.get_content_height,
         )
-        self.log(self)
-        self.log(box_model)
         return box_model
 
     def get_content_width(self, container: Size, viewport: Size) -> int:
@@ -346,7 +349,7 @@ class Widget(DOMNode):
             return self._content_width_cache[1]
 
         console = self.app.console
-        renderable = self.post_render(self.render())
+        renderable = self._render()
 
         width = measure(console, renderable, container.width)
         if self.fluid:
@@ -1427,13 +1430,14 @@ class Widget(DOMNode):
         if isinstance(renderable, str):
             renderable = Text.from_markup(renderable, justify=text_justify)
 
-        rich_style = self.rich_style
-        if isinstance(renderable, Text):
-            renderable.stylize(rich_style)
-            if text_justify is not None and renderable.justify is None:
-                renderable.justify = text_justify
-        else:
-            renderable = Styled(renderable, rich_style)
+        if (
+            isinstance(renderable, Text)
+            and text_justify is not None
+            and renderable.justify is None
+        ):
+            renderable.justify = text_justify
+
+        renderable = Styled(renderable, self.rich_style)
 
         return renderable
 
@@ -1613,6 +1617,12 @@ class Widget(DOMNode):
         render = "" if self.is_container else self.css_identifier_styled
         return render
 
+    def _render(self) -> ConsoleRenderable | RichCast:
+        renderable = self.render()
+        if isinstance(renderable, str):
+            return Text(renderable)
+        return renderable
+
     async def action(self, action: str) -> None:
         """Perform a given action, with this widget as the default namespace.
 

src/textual/widgets/_static.py

@@ -2,7 +2,9 @@ from __future__ import annotations
 
 from rich.console import RenderableType
 from rich.protocol import is_renderable
+from rich.text import Text
 
+from ..reactive import reactive
 from ..errors import RenderError
 from ..widget import Widget
 
@@ -41,21 +43,40 @@ class Static(Widget):
     }
     """
 
+    fluid = reactive(True, layout=True)
+    _renderable: RenderableType
+
     def __init__(
         self,
         renderable: RenderableType = "",
         *,
         fluid: bool = True,
+        markup: bool = True,
         name: str | None = None,
         id: str | None = None,
         classes: str | None = None,
     ) -> None:
 
         super().__init__(name=name, id=id, classes=classes)
-        self._renderable = renderable
         self.fluid = fluid
+        self.markup = markup
+        self.renderable = renderable
         _check_renderable(renderable)
 
+    @property
+    def renderable(self) -> RenderableType:
+        return self._renderable or ""
+
+    @renderable.setter
+    def renderable(self, renderable: RenderableType) -> None:
+        if isinstance(renderable, str):
+            if self.markup:
+                self._renderable = Text.from_markup(renderable)
+            else:
+                self._renderable = Text(renderable)
+        else:
+            self._renderable = renderable
+
     def render(self) -> RenderableType:
         """Get a rich renderable for the widget's content.
 
@@ -64,12 +85,12 @@ class Static(Widget):
         """
         return self._renderable
 
-    def update(self, renderable: RenderableType) -> None:
+    def update(self, renderable: RenderableType = "", home: bool = False) -> None:
         """Update the widget contents.
 
         Args:
             renderable (RenderableType): A new rich renderable.
         """
         _check_renderable(renderable)
-        self._renderable = renderable
+        self.renderable = renderable
         self.refresh(layout=True)

src/textual/widgets/_text_input.py

@@ -86,6 +86,8 @@ class TextWidgetBase(Widget):
         return display_text
 
     class Changed(Message, bubble=True):
+        namespace = "text_input"
+
         def __init__(self, sender: MessageTarget, value: str) -> None:
             """Message posted when the user changes the value in a TextInput
 
@@ -116,9 +118,17 @@ class TextInput(TextWidgetBase, can_focus=True):
         padding: 1;
         background: $surface;
         content-align: left middle;
+        color: $text;
+    }
+    TextInput .text-input--placeholder {
+        color: $text-muted;
     }
     """
 
+    COMPONENT_CLASSES = {
+        "text-input--placeholder",
+    }
+
     def __init__(
         self,
         *,
@@ -269,7 +279,10 @@ class TextInput(TextWidgetBase, can_focus=True):
         else:
             # The user has not entered text - show the placeholder
             display_text = Text(
-                self.placeholder, "dim", no_wrap=True, overflow="ignore"
+                self.placeholder,
+                self.get_component_rich_style("text-input--placeholder"),
+                no_wrap=True,
+                overflow="ignore",
             )
             if show_cursor:
                 display_text = self._apply_cursor_to_text(display_text, 0)