log selection

Author: willmcgugan

src/textual/screen.py

@@ -870,6 +870,7 @@ def action_copy_text(self) -> None:
         selection = self.get_selected_text()
         if selection is not None:
             self.app.copy_to_clipboard(selection)
+            self.notify(selection)
 
     def action_maximize(self) -> None:
         """Action to maximize the currently focused widget."""

src/textual/strip.py

@@ -672,3 +672,24 @@ def text_align(self, width: int, align: AlignHorizontal) -> Strip:
                     line_pad(self._segments, width - self.cell_length, 0, Style.null()),
                     width,
                 )
+
+    def apply_offsets(self, x: int, y: int) -> Strip:
+        """Apply offsets used in text selection.
+
+        Args:
+            x: Offset on X axis (column).
+            y: Offset on Y axis (row).
+
+        Returns:
+            New strip.
+        """
+        segments = self._segments
+        strip_segments: list[Segment] = []
+        for segment in segments:
+            text, style, _ = segment
+            offset_style = Style.from_meta({"offset": (x, y)})
+            strip_segments.append(
+                Segment(text, style + offset_style if style else offset_style)
+            )
+            x += len(segment.text)
+        return Strip(strip_segments, self._cell_length)

src/textual/widgets/_log.py

@@ -5,7 +5,6 @@
 
 from rich.cells import cell_len
 from rich.highlighter import Highlighter, ReprHighlighter
-from rich.segment import Segment
 from rich.style import Style
 from rich.text import Text
 
@@ -15,6 +14,7 @@
 from textual.geometry import Size
 from textual.reactive import var
 from textual.scroll_view import ScrollView
+from textual.selection import Selection
 from textual.strip import Strip
 
 if TYPE_CHECKING:
@@ -26,6 +26,7 @@
 class Log(ScrollView, can_focus=True):
     """A widget to log text."""
 
+    ALLOW_SELECT = True
     DEFAULT_CSS = """
     Log {
         background: $surface;
@@ -75,6 +76,11 @@ def __init__(
         self._render_line_cache: LRUCache[int, Strip] = LRUCache(1024)
         self.highlighter: Highlighter = ReprHighlighter()
         """The Rich Highlighter object to use, if `highlight=True`"""
+        self._clear_y = 0
+
+    @property
+    def allow_select(self) -> bool:
+        return True
 
     @property
     def lines(self) -> Sequence[str]:
@@ -251,8 +257,21 @@ def clear(self) -> Self:
         self._render_line_cache.clear()
         self._updates += 1
         self.virtual_size = Size(0, 0)
+        self._clear_y = 0
         return self
 
+    def get_selection(self, selection: Selection) -> tuple[str, str] | None:
+        """Get the text under the selection.
+
+        Args:
+            selection: Selection information.
+
+        Returns:
+            Tuple of extracted text and ending (typically "\n" or " "), or `None` if no text could be extracted.
+        """
+        text = "\n".join(self._lines)
+        return selection.extract(text), "\n"
+
     def render_line(self, y: int) -> Strip:
         """Render a line of content.
 
@@ -284,6 +303,7 @@ def _render_line(self, y: int, scroll_x: int, width: int) -> Strip:
         line = self._render_line_strip(y, rich_style)
         assert line._cell_length is not None
         line = line.crop_extend(scroll_x, scroll_x + width, rich_style)
+        line = line.apply_offsets(scroll_x, y)
         return line
 
     def _render_line_strip(self, y: int, rich_style: Style) -> Strip:
@@ -296,18 +316,30 @@ def _render_line_strip(self, y: int, rich_style: Style) -> Strip:
         Returns:
             An uncropped Strip.
         """
-        if y in self._render_line_cache:
+        selection = self.selection
+        if y in self._render_line_cache and self.selection is None:
             return self._render_line_cache[y]
 
         _line = self._process_line(self._lines[y])
 
+        line_text = Text(_line, style=rich_style, no_wrap=True)
         if self.highlight:
-            line_text = self.highlighter(Text(_line, style=rich_style, no_wrap=True))
-            line = Strip(line_text.render(self.app.console), cell_len(_line))
-        else:
-            line = Strip([Segment(_line, rich_style)], cell_len(_line))
+            line_text = self.highlighter(line_text)
+        if selection is not None:
+            if (select_span := selection.get_span(y - self._clear_y)) is not None:
+                start, end = select_span
+                if end == -1:
+                    end = len(line_text)
+
+                selection_style = self.screen.get_component_rich_style(
+                    "screen--selection"
+                )
+                line_text.stylize(selection_style, start, end)
+
+        line = Strip(line_text.render(self.app.console), cell_len(_line))
 
-        self._render_line_cache[y] = line
+        if selection is not None:
+            self._render_line_cache[y] = line
         return line
 
     def refresh_lines(self, y_start: int, line_count: int = 1) -> None: