renderer refactor

examples/README.md

@@ -0,0 +1,5 @@
+# Examples
+
+Run any of these examples to demonstrate a features.
+
+These examples may not be feature complete, but they should be somewhat useful and a good starting point for your own code.

examples/test_layout.py

@@ -0,0 +1,20 @@
+from rich import print
+from rich.console import Console
+
+from textual.geometry import Offset, Region
+from textual.widgets import Placeholder
+
+
+from textual.views import WindowView
+
+p = Placeholder(height=10)
+view = WindowView(p)
+
+console = Console()
+view.layout.reflow(console, 30, 25, Offset(0, 3))
+
+print(view.layout._layout_map.widgets)
+
+console.print(view.layout.render(console))
+
+# console.print(view.layout.render(console, Region(100, 2, 10, 10)))

examples/vertical.py

@@ -0,0 +1,19 @@
+from textual import events
+from textual.app import App
+
+from textual.views import WindowView
+from textual.widgets import Placeholder
+
+
+class MyApp(App):
+    async def on_mount(self, event: events.Mount) -> None:
+        window1 = WindowView(Placeholder(height=20))
+        # window2 = WindowView(Placeholder(height=20))
+
+        # window1.scroll_x = -10
+        # window1.scroll_y = 5
+
+        await self.view.dock(window1, edge="left")
+
+
+MyApp.run(log="textual.log")

src/textual/__init__.py

@@ -1,8 +1,17 @@
 from typing import Any
 
+__all__ = ["log", "panic"]
+
 
 def log(*args: Any) -> None:
     from ._context import active_app
 
     app = active_app.get()
     app.log(*args)
+
+
+def panic(*args: Any) -> None:
+    from ._context import active_app
+
+    app = active_app.get()
+    app.panic(*args)

src/textual/app.py

@@ -97,7 +97,7 @@ class App(MessagePump):
         self.mouse_over: Widget | None = None
         self.mouse_captured: Widget | None = None
         self._driver: Driver | None = None
-        self._tracebacks: list[Traceback] = []
+        self._exit_renderables: list[RenderableType] = []
 
         self._docks: list[Dock] = []
         self._action_targets = {"app", "view"}
@@ -231,16 +231,19 @@ class App(MessagePump):
         if widget is not None:
             await widget.post_message(events.MouseCapture(self, self.mouse_position))
 
-    def panic(self, traceback: Traceback | None = None) -> None:
+    def panic(self, *renderables: RenderableType) -> None:
         """Exits the app with a traceback.
 
         Args:
             traceback (Traceback, optional): Rich Traceback object or None to generate one
                 for the most recent exception. Defaults to None.
         """
-        if traceback is None:
+
-            traceback = Traceback(show_locals=True)
+        if not renderables:
-        self._tracebacks.append(traceback)
+            renderables = (
+                Traceback(show_locals=True, width=None, locals_max_length=5),
+            )
+        self._exit_renderables.extend(renderables)
         self.close_messages_no_wait()
 
     async def process_messages(self) -> None:
@@ -283,8 +286,8 @@ class App(MessagePump):
                 self.panic()
             finally:
                 driver.stop_application_mode()
-                if self._tracebacks:
+                if self._exit_renderables:
-                    for traceback in self._tracebacks:
+                    for traceback in self._exit_renderables:
                         self.error_console.print(traceback)
                 if self.log_file is not None:
                     self.log_file.close()
@@ -339,7 +342,7 @@ class App(MessagePump):
                     console.file.write("\x1bP=2s\x1b\\")
                     console.file.flush()
             except Exception:
-                self.panic(Traceback(show_locals=True))
+                self.panic()
 
     def display(self, renderable: RenderableType) -> None:
         if not self._closed:

src/textual/geometry.py

@@ -167,6 +167,22 @@ class Region(NamedTuple):
     def __bool__(self) -> bool:
         return bool(self.width and self.height)
 
+    @property
+    def x_extents(self) -> tuple[int, int]:
+        return (self.x, self.x + self.width)
+
+    @property
+    def y_extents(self) -> tuple[int, int]:
+        return (self.y, self.y + self.height)
+
+    @property
+    def x_end(self) -> int:
+        return self.x + self.width
+
+    @property
+    def y_end(self) -> int:
+        return self.y + self.height
+
     @property
     def area(self) -> int:
         """Get the area within the region."""
@@ -192,6 +208,14 @@ class Region(NamedTuple):
         x, y, width, height = self
         return x, y, x + width, y + height
 
+    @property
+    def x_range(self) -> range:
+        return range(self.x, self.x_end)
+
+    @property
+    def y_range(self) -> range:
+        return range(self.y, self.y_end)
+
     def __add__(self, other: Any) -> Region:
         if isinstance(other, tuple):
             ox, oy = other

src/textual/layout.py

@@ -15,7 +15,7 @@ from rich.console import Console, ConsoleOptions, RenderResult, RenderableType
 from rich.segment import Segment, SegmentLines
 from rich.style import Style
 
-from . import log
+from . import log, panic
 from ._loop import loop_last
 from .layout_map import LayoutMap
 from ._lines import crop_lines
@@ -101,6 +101,9 @@ class Layout(ABC):
     ) -> ReflowResult:
         self.reset()
 
+        self.width = width
+        self.height = height
+
         map = self.generate_map(
             console,
             Dimensions(width, height),
@@ -131,8 +134,6 @@ class Layout(ABC):
         hidden_widgets = old_widgets - new_widgets
 
         self._layout_map = map
-        self.width = width
-        self.height = height
 
         # Copy renders if the size hasn't changed
         new_renders = {
@@ -255,9 +256,10 @@ class Layout(ABC):
         if self.map is not None:
             for region, order, clip in self.map.values():
                 region = region.intersection(clip)
-                if region and (region in screen_region):  # type: ignore
+                if region and (region in screen_region):
-                    for y in range(region.y, region.y + region.height):
+                    region_cuts = region.x_extents
-                        cuts_sets[y].update({region.x, region.x + region.width})
+                    for y in region.y_range:
+                        cuts_sets[y].update(region_cuts)
 
         # Sort the cuts for each line
         self._cuts = [sorted(cut_set) for cut_set in cuts_sets]
@@ -265,9 +267,6 @@ class Layout(ABC):
 
     def _get_renders(self, console: Console) -> Iterable[tuple[Region, Region, Lines]]:
         _rich_traceback_guard = True
-        width = self.width
-        height = self.height
-        screen_region = Region(0, 0, width, height)
         layout_map = self.map
 
         if layout_map:
@@ -292,12 +291,12 @@ class Layout(ABC):
 
             if not widget.is_visual:
                 continue
+
             region_lines = self.renders.get(widget)
             if region_lines is not None:
-                yield region_lines
+                region, clip, lines = region_lines
-                continue
+            else:
-
+                lines = render(widget, region.width, region.height)
-            lines = render(widget, region.width, region.height)
             if region in clip:
                 self.renders[widget] = (region, clip, lines)
                 yield region, clip, lines
@@ -308,11 +307,10 @@ class Layout(ABC):
                 self.renders[widget] = (region, clip, lines)
                 splits = [delta_x, delta_x + new_region.width]
 
+                lines = lines[delta_y : delta_y + new_region.height]
+
                 divide = Segment.divide
-                lines = [
+                lines = [list(divide(line, splits))[1] for line in lines]
-                    list(divide(line, splits))[1]
-                    for line in lines[delta_y : delta_y + new_region.height]
-                ]
                 yield region, clip, lines
 
     @classmethod
@@ -331,7 +329,7 @@ class Layout(ABC):
     def render(
         self,
         console: Console,
-        clip: Region = None,
+        crop: Region = None,
     ) -> SegmentLines:
         """Render a layout.
 
@@ -345,8 +343,10 @@ class Layout(ABC):
         width = self.width
         height = self.height
         screen = Region(0, 0, width, height)
-        clip = clip or screen
+
-        clip_x, clip_y, clip_x2, clip_y2 = clip.corners
+        crop_region = crop or Region(0, 0, self.width, self.height)
+
+        # clip_x, clip_y, clip_x2, clip_y2 = clip.corners
 
         divide = Segment.divide
 
@@ -363,27 +363,45 @@ class Layout(ABC):
         ]
         # Go through all the renders in reverse order and fill buckets with no render
         renders = self._get_renders(console)
+        clip_y, clip_y2 = crop_region.y_extents
         for region, clip, lines in chain(
             renders, [(screen, screen, background_render)]
         ):
-            for y, line in enumerate(lines, region.y):
+            # clip = clip.intersection(crop_region)
+            render_region = region.intersection(clip)
+            for y, line in enumerate(lines, render_region.y):
                 if clip_y > y > clip_y2:
                     continue
-                first_cut = clamp(region.x, clip_x, clip_x2)
+                # first_cut = clamp(render_region.x, clip_x, clip_x2)
-                last_cut = clamp(region.x + region.width, clip_x, clip_x2)
+                # last_cut = clamp(render_region.x + render_region.width, clip_x, clip_x2)
+                first_cut = render_region.x
+                last_cut = render_region.x_end
                 final_cuts = [cut for cut in cuts[y] if (last_cut >= cut >= first_cut)]
-                if len(final_cuts) > 1:
+                # final_cuts = cuts[y]
-                    if final_cuts == [region.x, region.x + region.width]:
+
-                        cut_segments = [line]
+                if final_cuts == render_region.y_extents:
-                    else:
+                    cut_segments = [line]
-                        relative_cuts = [cut - region.x for cut in final_cuts]
+                else:
-                        _, *cut_segments = divide(line, relative_cuts)
+                    render_x = render_region.x
-                    for cut, segments in zip(final_cuts, cut_segments):
+                    relative_cuts = [cut - render_x for cut in final_cuts]
-                        if chops[y][cut] is None:
+                    _, *cut_segments = divide(line, relative_cuts)
-                            chops[y][cut] = segments
+                for cut, segments in zip(final_cuts, cut_segments):
+                    if chops[y][cut] is None:
+                        chops[y][cut] = segments
 
         # Assemble the cut renders in to lists of segments
-        output_lines = list(self._assemble_chops(chops[clip_y:clip_y2]))
+        output_lines = list(self._assemble_chops(chops))
+
+        def width_view(line: list[Segment]) -> list[Segment]:
+            if line:
+                div_lines = list(Segment.divide(line, [crop_x, crop_x2]))
+                line = div_lines[1] if len(div_lines) > 1 else div_lines[0]
+            return line
+
+        if crop is not None:
+            crop_x, crop_y, crop_x2, crop_y2 = crop_region.corners
+            output_lines = [width_view(line) for line in output_lines[crop_y:crop_y2]]
+
         return SegmentLines(output_lines, new_lines=True)
 
     def __rich_console__(
@@ -401,9 +419,9 @@ class Layout(ABC):
         )
 
         self.renders[widget] = (region, clip, new_lines)
-        update_lines = self.render(console, region.intersection(clip)).lines
 
-        clipped_region = region.intersection(clip)
+        update_region = region.intersection(clip)
-        update = LayoutUpdate(update_lines, clipped_region.x, clipped_region.y)
+        update_lines = self.render(console, update_region).lines
+        update = LayoutUpdate(update_lines, update_region.x, update_region.y)
 
         return update

src/textual/layouts/vertical.py

@@ -14,7 +14,7 @@ from ..widget import Widget
 class VerticalLayout(Layout):
     def __init__(self, *, z: int = 0, gutter: tuple[int, int] | None = None):
         self.z = z
-        self.gutter = gutter or (0, 1)
+        self.gutter = gutter or (1, 1)
         self._widgets: list[Widget] = []
         super().__init__()
 
@@ -49,8 +49,9 @@ class VerticalLayout(Layout):
                 lines = console.render_lines(
                     renderable, console.options.update_width(render_width)
                 )
+
                 region = Region(x, y, render_width, len(lines))
-                add_widget(widget, region, viewport)
+                add_widget(widget, region - scroll, viewport)
             else:
                 add_widget(
                     widget,

src/textual/message_pump.py

@@ -193,7 +193,7 @@ class MessagePump:
             except CancelledError:
                 raise
             except Exception as error:
-                self.app.panic(Traceback(show_locals=True))
+                self.app.panic()
                 break
             finally:
                 if isinstance(message, events.Event) and self._message_queue.empty():

src/textual/view.py

@@ -58,7 +58,7 @@ class View(Widget):
 
     @property
     def virtual_size(self) -> Dimensions:
-        return self.layout.map.size
+        return self.layout.map.size if self.layout.map else Dimensions(0, 0)
 
     # virtual_width: Reactive[int | None] = Reactive(None)
     # virtual_height: Reactive[int | None] = Reactive(None)

src/textual/views/_window_view.py

@@ -1,17 +1,26 @@
 from __future__ import annotations
 
+from rich.console import RenderableType
+
 from ..layouts.vertical import VerticalLayout
 from ..view import View
 from ..widget import Widget
+from ..widgets import Static
 
 
 class WindowView(View, layout=VerticalLayout):
     def __init__(
-        self, *, gutter: tuple[int, int] = (1, 1), name: str | None = None
+        self,
+        widget: RenderableType | Widget,
+        *,
+        gutter: tuple[int, int] = (1, 1),
+        name: str | None = None
     ) -> None:
         self.gutter = gutter
-        super().__init__(name=name)
+        layout = VerticalLayout()
+        layout.add(widget if isinstance(widget, Widget) else Static(widget))
+        super().__init__(name=name, layout=layout)
 
-    async def update(self, widget: Widget) -> None:
+    async def update(self, widget: Widget | RenderableType) -> None:
         self.layout = VerticalLayout(gutter=self.gutter)
-        self.layout.add(widget)
+        self.layout.add(widget if isinstance(widget, Widget) else Static(widget))

src/textual/widgets/_placeholder.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 from rich import box
 from rich.align import Align
 from rich.console import RenderableType
@@ -19,6 +21,11 @@ class Placeholder(Widget, can_focus=True):
     has_focus: Reactive[bool] = Reactive(False)
     mouse_over: Reactive[bool] = Reactive(False)
     style: Reactive[str] = Reactive("")
+    height: Reactive[int | None] = Reactive(None)
+
+    def __init__(self, *, name: str | None = None, height: int | None = None) -> None:
+        super().__init__(name=name)
+        self.height = height
 
     def __rich_repr__(self) -> rich.repr.RichReprResult:
         yield "name", self.name
@@ -34,6 +41,7 @@ class Placeholder(Widget, can_focus=True):
             border_style="green" if self.mouse_over else "blue",
             box=box.HEAVY if self.has_focus else box.ROUNDED,
             style=self.style,
+            height=self.height,
         )
 
     async def on_focus(self, event: events.Focus) -> None:

src/textual/widgets/_scroll_view.py

@@ -11,6 +11,8 @@ from ..scrollbar import ScrollTo, ScrollBar
 from ..geometry import clamp
 from ..page import Page
 from ..view import View
+
+
 from ..reactive import Reactive
 
 
@@ -23,10 +25,12 @@ class ScrollView(View):
         style: StyleType = "",
         fluid: bool = True,
     ) -> None:
+        from ..views import WindowView
+
         self.fluid = fluid
         self.vscroll = ScrollBar(vertical=True)
         self.hscroll = ScrollBar(vertical=False)
-        self.page = Page(renderable or "", style=style)
+        self.window = WindowView(renderable or "")
         layout = GridLayout()
         layout.add_column("main")
         layout.add_column("vscroll", size=1)
@@ -46,33 +50,33 @@ class ScrollView(View):
     target_y: Reactive[float] = Reactive(0, repaint=False)
 
     def validate_x(self, value: float) -> float:
-        return clamp(value, 0, self.page.virtual_size.width - self.size.width)
+        return clamp(value, 0, self.window.virtual_size.width - self.size.width)
 
     def validate_target_x(self, value: float) -> float:
-        return clamp(value, 0, self.page.virtual_size.width - self.size.width)
+        return clamp(value, 0, self.window.virtual_size.width - self.size.width)
 
     def validate_y(self, value: float) -> float:
-        return clamp(value, 0, self.page.virtual_size.height - self.size.height)
+        return clamp(value, 0, self.window.virtual_size.height - self.size.height)
 
     def validate_target_y(self, value: float) -> float:
-        return clamp(value, 0, self.page.virtual_size.height - self.size.height)
+        return clamp(value, 0, self.window.virtual_size.height - self.size.height)
 
     async def watch_x(self, new_value: float) -> None:
-        self.page.scroll_x = round(new_value)
+        self.window.scroll_x = round(new_value)
         self.hscroll.position = round(new_value)
 
     async def watch_y(self, new_value: float) -> None:
-        self.page.scroll_y = round(new_value)
+        self.window.scroll_y = round(new_value)
         self.vscroll.position = round(new_value)
 
     async def update(self, renderabe: RenderableType) -> None:
-        self.page.update(renderabe)
+        await self.window.update(renderabe)
         self.require_repaint()
 
     async def on_mount(self, event: events.Mount) -> None:
         assert isinstance(self.layout, GridLayout)
         self.layout.place(
-            content=self.page,
+            content=self.window,
             vscroll=self.vscroll,
             hscroll=self.hscroll,
         )
@@ -132,7 +136,7 @@ class ScrollView(View):
 
     async def key_end(self) -> None:
         self.target_x = 0
-        self.target_y = self.page.virtual_size.height - self.size.height
+        self.target_y = self.window.virtual_size.height - self.size.height
         self.animate("x", self.target_x, duration=1, easing="out_cubic")
         self.animate("y", self.target_y, duration=1, easing="out_cubic")
 
@@ -143,8 +147,9 @@ class ScrollView(View):
         self.animate("y", self.target_y, duration=1, easing="out_cubic")
 
     async def on_resize(self, event: events.Resize) -> None:
+        return
         if self.fluid:
-            self.page.update()
+            self.window.update()
 
     async def message_scroll_up(self, message: Message) -> None:
         self.page_up()
@@ -169,16 +174,16 @@ class ScrollView(View):
     async def message_page_update(self, message: Message) -> None:
         self.x = self.validate_x(self.x)
         self.y = self.validate_y(self.y)
-        self.vscroll.virtual_size = self.page.virtual_size.height
+        self.vscroll.virtual_size = self.window.virtual_size.height
         self.vscroll.window_size = self.size.height
 
         assert isinstance(self.layout, GridLayout)
 
         if self.layout.show_column(
-            "vscroll", self.page.virtual_size.height > self.size.height
+            "vscroll", self.window.virtual_size.height > self.size.height
         ):
             self.require_layout()
         if self.layout.show_row(
-            "hscroll", self.page.virtual_size.width > self.size.width
+            "hscroll", self.window.virtual_size.width > self.size.width
         ):
             self.require_layout()