long placeholder

Author: willmcgugan

CHANGELOG.md

@@ -24,6 +24,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Added `Screen.size` https://github.com/Textualize/textual/pull/6105
 - Added `compact` to Binding.Group https://github.com/Textualize/textual/pull/6132
 - Added `Screen.get_hover_widgets_at` https://github.com/Textualize/textual/pull/6132
+- Added `Content.wrap`
 
 ### Fixed
 

src/textual/content.py

@@ -869,6 +869,23 @@ def iter_content() -> Iterable[Content]:
 
         return Content("".join(text), spans, total_cell_length)
 
+    def wrap(
+        self, width: int, align: TextAlign = "left", overflow: TextOverflow = "fold"
+    ) -> list[Content]:
+        """Wrap text so that it fits within the given dimensions.
+
+        Args:
+            width: Maximum width of the line (in cells).
+            align: Alignment of lines.
+            overflow: Overflow of lines (what happens when the text doesn't fit).
+
+        Returns:
+            A list of Content objects, one per line.
+        """
+        lines = self._wrap_and_format(width, align, overflow)
+        content_lines = [line.content for line in lines]
+        return content_lines
+
     def get_style_at_offset(self, offset: int) -> Style:
         """Get the style of a character at give offset.
 

src/textual/widgets/_text_area.py

@@ -1206,24 +1206,24 @@ def render_line(self, y: int) -> Strip:
         Returns:
             A rendered line.
         """
-        if y == 0 and not self.text and self.placeholder:
-            style = self.get_visual_style("text-area--placeholder")
-            content = (
-                Content(self.placeholder)
-                if isinstance(self.placeholder, str)
-                else self.placeholder
-            )
-            content = content.stylize(style)
-            if self._draw_cursor:
-                theme = self._theme
-                cursor_style = theme.cursor_style if theme else None
-                if cursor_style:
-                    content = content.stylize(
-                        ContentStyle.from_rich_style(cursor_style), 0, 1
-                    )
-            return Strip(
-                content.render_segments(self.visual_style), content.cell_length
+
+        if not self.text and self.placeholder:
+            placeholder_lines = Content.from_text(self.placeholder).wrap(
+                self.content_size.width
             )
+            if y < len(placeholder_lines):
+                style = self.get_visual_style("text-area--placeholder")
+                content = placeholder_lines[y].stylize(style)
+                if self._draw_cursor and y == 0:
+                    theme = self._theme
+                    cursor_style = theme.cursor_style if theme else None
+                    if cursor_style:
+                        content = content.stylize(
+                            ContentStyle.from_rich_style(cursor_style), 0, 1
+                        )
+                return Strip(
+                    content.render_segments(self.visual_style), content.cell_length
+                )
 
         scroll_x, scroll_y = self.scroll_offset
         absolute_y = scroll_y + y

tests/snapshot_tests/test_snapshots.py

@@ -4626,3 +4626,27 @@ def compose(self) -> ComposeResult:
             yield Header()
 
     assert snap_compare(HeaderApp())
+
+
+def test_long_textarea_placeholder(snap_compare) -> None:
+
+    TEXT = """I must not fear.
+Fear is the mind-killer.
+Fear is the little-death that brings total obliteration.
+I will face my fear.
+I will permit it to pass over me and through me.
+And when it has gone past, I will turn the inner eye to see its path.
+Where the fear has gone there will be nothing. Only I will remain."""
+
+    class PlaceholderApp(App):
+
+        CSS = """
+        TextArea {
+            width: 50%;
+        }
+        """
+
+        def compose(self) -> ComposeResult:
+            yield TextArea(placeholder=TEXT)
+
+    assert snap_compare(PlaceholderApp())

tests/test_content.py

@@ -349,3 +349,19 @@ def test_add_spans() -> None:
         Span(7, 9, style="blue"),
     ]
     assert content.spans == expected
+
+
+def test_wrap() -> None:
+    content = Content.from_markup("[green]Hello, [b]World, One two three[/b]")
+    wrapped = content.wrap(6)
+    print(wrapped)
+    expected = [
+        Content("Hello,", spans=[Span(0, 6, style="green")]),
+        Content("World,", spans=[Span(0, 6, style="green"), Span(0, 6, style="b")]),
+        Content("One", spans=[Span(0, 3, style="green"), Span(0, 3, style="b")]),
+        Content("two", spans=[Span(0, 3, style="green"), Span(0, 3, style="b")]),
+        Content("three", spans=[Span(0, 5, style="green"), Span(0, 5, style="b")]),
+    ]
+    assert len(wrapped) == len(expected)
+    for line1, line2 in zip(wrapped, expected):
+        assert line1.is_same(line2)