using RichLog widget instead of ScrollView for diff_areas (TextScrollView) (#32)

This change lets use remove the code related to rendering each line of text manually as it is now handled by `RichLog`.
This also enables horizontal scroll.

Author: Vipul-Cariappa

ui/scrollable_area.py

@@ -1,81 +1,28 @@
 from __future__ import annotations
+from textual.widgets import RichLog
 
-from textual.reactive import Reactive
-from textual.widgets import Static
-from textual.scroll_view import ScrollView
-from textual.app import App, ComposeResult
-from textual.geometry import Size
-from rich.console import RenderableType
-from textual.widgets import Markdown
-from rich.text import Text
 
-
-from textual.app import App, ComposeResult
-from textual.geometry import Size
-from textual.strip import Strip
-from textual.scroll_view import ScrollView
-
-from rich.segment import Segment
-
-class TextScrollView(ScrollView):
+class TextScrollView(RichLog):
     COMPONENT_CLASSES = {
         "box",         # Class for the main text container
         "rich-text--line",   # Class for each line of text
     }
     DEFAULT_CSS = """
     TextScrollView {
         height: 100%;
+        scrollbar-size: 1 1;
     }
     """
 
-    def __init__(self, title = "", lines: list[str] = None, component_id: str = None) -> None:
-        super().__init__()
+    def __init__(self, title: str = "", component_id: str = None) -> None:
+        super().__init__(name=title, auto_scroll=True, markup=True)
         self.border_title = title
-        self.lines = lines if lines is not None else []
-        self.lines = lines
-        if lines:
-            self.virtual_size = Size(0, len(lines))
-        else:
-            self.virtual_size = Size(0, 5)
-
         if component_id:
             self.id = component_id
 
-    def update_virtual_size(self) -> None:
-        """Update the virtual size based on the number of lines."""
-        self.virtual_size = Size(0, len(self.lines))
-
-    def render_line(self, y: int) -> Strip:
-        """Render a line of the widget. y is relative to the top of the widget."""
-        scroll_x, scroll_y = self.scroll_offset
-        y += scroll_y
-
-        if self.lines:
-            if y >= len(self.lines):
-                return Strip.blank(self.size.width)
-
-            rich_text = Text.from_markup(self.lines[y])
-            segments = list(rich_text.render(self.app.console))
-
-            strip = Strip(segments, sum(segment.cell_length for segment in segments))
-            strip = strip.crop(scroll_x, scroll_x + self.size.width)
-            return strip
-        return Strip.blank(self.size.width)
-    
     def append(self, lines: list[str]):
-        if not self.lines:
-            self.lines = []
-
-        self.lines += lines
-        self.update_virtual_size()
-        self.refresh(layout=True)
-        self.scroll_to(y = self.max_scroll_y, speed=300)
+        self.write("\n".join(lines))
 
     def text(self, lines: list[str]):
-        if not self.lines:
-            self.lines = []
-
-        self.lines = lines
-        self.update_virtual_size()
-        self.refresh(layout=True)
-        self.scroll_to(y = self.max_scroll_y, speed=300)
+        self.clear()
+        self.append(lines)