Merge pull request #5842 from TomJGooding/fix-text-area-fix-initial-flicker

fix(text area): fix initial flicker in rendering

Author: willmcgugan

CHANGELOG.md

@@ -5,6 +5,11 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
+## Unreleased
+
+### Fixed
+
+- Fixed issues with initial flicker in `TextArea` rendering https://github.com/Textualize/textual/issues/5841
 
 ## Unreleased 
 

src/textual/widgets/_text_area.py

@@ -500,6 +500,11 @@ def __init__(
         self._cursor_offset = (0, 0)
         """The virtual offset of the cursor (not screen-space offset)."""
 
+        self.set_reactive(TextArea.soft_wrap, soft_wrap)
+        self.set_reactive(TextArea.read_only, read_only)
+        self.set_reactive(TextArea.show_line_numbers, show_line_numbers)
+        self.set_reactive(TextArea.line_number_start, line_number_start)
+
         self._set_document(text, language)
 
         self.language = language
@@ -510,11 +515,6 @@ def __init__(
         reactive is set as a string, the watcher will update this attribute to the
         corresponding `TextAreaTheme` object."""
 
-        self.set_reactive(TextArea.soft_wrap, soft_wrap)
-        self.set_reactive(TextArea.read_only, read_only)
-        self.set_reactive(TextArea.show_line_numbers, show_line_numbers)
-        self.set_reactive(TextArea.line_number_start, line_number_start)
-
         self.tab_behavior = tab_behavior
 
         if tooltip is not None:
@@ -1021,7 +1021,7 @@ def wrap_width(self) -> int:
         width, _ = self.scrollable_content_region.size
         cursor_width = 1
         if self.soft_wrap:
-            return width - self.gutter_width - cursor_width
+            return max(0, width - self.gutter_width - cursor_width)
         return 0
 
     def _rewrap_and_refresh_virtual_size(self) -> None: