gui: use incremental layout in UITextArea

CHANGELOG.md

@@ -7,6 +7,7 @@ Arcade [PyPi Release History](https://pypi.org/project/arcade/#history) page.
 
 - GUI
   - Fix a bug, where the caret of UIInputText was misplaced after resizing the widget
+  - Use incremental layout for UIScrollArea to improve performance of changing text
 
 ## 3.3.2
 

arcade/examples/gui/1_layouts.py

@@ -14,6 +14,7 @@
 from datetime import datetime
 
 import arcade
+import arcade.gui
 from arcade.gui import UIAnchorLayout, UIImage, UITextArea
 
 arcade.resources.load_kenney_fonts()
@@ -186,5 +187,5 @@ def main():
     window.run()
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     main()

arcade/gui/experimental/scroll_area.py

@@ -46,9 +46,9 @@ def __init__(self, scroll_area: UIScrollArea, vertical: bool = True):
 
         bind(self, "_thumb_hover", UIScrollBar.trigger_render)
         bind(self, "_dragging", UIScrollBar.trigger_render)
-        bind(scroll_area, "scroll_x", UIScrollBar.trigger_full_render)
-        bind(scroll_area, "scroll_y", UIScrollBar.trigger_full_render)
-        bind(scroll_area, "rect", UIScrollBar.trigger_full_render)
+        bind(scroll_area, "scroll_x", self.trigger_full_render, weak=True)
+        bind(scroll_area, "scroll_y", self.trigger_full_render, weak=True)
+        bind(scroll_area, "rect", self.trigger_full_render, weak=True)
 
     def on_event(self, event: UIEvent) -> bool | None:
         # check if we are scrollable

arcade/gui/widgets/text.py

@@ -855,14 +855,14 @@ def __init__(
             ),
         )
 
-        self.layout = pyglet.text.layout.ScrollableTextLayout(
+        self.layout = pyglet.text.layout.IncrementalTextLayout(
             self.doc,
             width=int(self.content_width),
             height=int(self.content_height),
             multiline=multiline,
         )
 
-        bind(self, "rect", self._update_layout)
+        bind(self, "rect", UITextArea._update_layout)
 
     def fit_content(self):
         """Set the width and height of the text area to contain the whole text."""
@@ -894,6 +894,7 @@ def _update_layout(self):
             layout.begin_update()
             layout.width = content_width
             layout.height = content_height
+            layout.y = 0  # reset y position to 0 (Required by IncrementalTextLayout)
             layout.end_update()
 
     @override